Rabbi Eliyahu Tavger
Jerusalem

New Investigations into Tekhelet

For approximately fifteen hundred years, Tekhelet has been absent from the Jewish people.[1] In recent generations, attempts began to identify the lost Tekhelet. The first to undertake this was the Radzyner Rebbe, R’ Gershon Henoch, who devoted three sefarim to the subject: Sefunei Temunei Chol, Pesil Tekhelet, and Ein HaTekhelet. It should be noted that his time was not yet ripe for such an undertaking. Detailed information concerning the life and biology of various animals was then lacking, and information contained in ancient historical works was also not widely known. Under such conditions, making an identification was extremely difficult.

After him came Rav Y. A. Halevi Herzog, who opened the subject much more broadly through his extensive knowledge of ancient general history. He too wrote on the subject, including a lengthy article in English[2] and several articles in the journal HaHed.[3] Even in his time, however, much information about Mediterranean marine life was still lacking. Experts in various fields subsequently continued dealing with the subject, and their findings were summarized in the English work mentioned above.

One should also mention the articles of R’ Yechiel Michel Tukachinsky in Ir HaKodesh VeHaMikdash, vol. 5, as well as the articles of R’ Betzalel Naor in BeYam Derech, Reishis Oni, and Or HaMizrach, vol. 22, no. 2. My friend R’ Menachem Burstein served as a collector of all the various shittos in his sefer HaTekhelet, where he gathered the different approaches together with detailed information relevant to Tekhelet.

In this article, I do not intend to present the reader with all the different shittos or to argue with them. Rather, I will present the matter as, in my opinion, it emerges from the sources themselves. The reader should know that this article was preceded by a long and thorough investigation of our own sources and of non-Jewish sources in their original languages, across a number of different fields,[4] as well as consultation with experts in those fields. This article is the condensed result of all that work.

Tekhelet Must Be Dyed Specifically with the Blood of a Chilazon

The Gemara says:[5] Abaye asked Rav Shmuel bar Rav Yehudah, “How is this Tekhelet dyed?” He replied, “We bring the blood of the chilazon together with other ingredients, place them in a pot, and boil them,” etc. Similarly, the Beraisa states:[6] “This is the chilazon… and with its blood they dye Tekhelet,” etc.

It is also clear from the Gemara that if a similar shade was produced with some other material, it is possul for the mitzvah of tzitzis. The Gemara says:[7] Rava asked why the Torah mentions Yetzias Mitzrayim in connection with ribbis and again with tzitzis. Hashem says, in effect: “I am the One Who distinguished… and I am the One Who will ultimately punish… one who hangs kela ilan on his garment and claims that it is Tekhelet.”

The Sifrei likewise states:[8] “‘I am Hashem your God’ — what is the relevance here? So that a person should not say: I will use other dyes or kela ilan, which look like Tekhelet, and who will know?”

There is, however, room to investigate whether other substances are possul because the mitzvah specifically requires dyeing with the blood of a chilazon, or whether there is some other advantage inherent in chilazon dye that other dyes lack — for example, permanence and durability.

At first glance, one could perhaps understand the Gemara[9] this way. The Gemara discusses testing Tekhelet: Rav Yitzchak the son of Rav Yehudah would bring certain substances, including aged urine, soak the sample overnight until morning, and if its color faded it was possul; if the color did not fade it was kosher. As explained there, the dye whose appearance faded was the aforementioned kela ilan.

Similarly, the Rambam writes:[10]

The Tekhelet mentioned regarding tzitzis must be dyed with a particular known dyeing process which retains its beauty and does not change. Anything not dyed with that process is possul for tzitzis even if it resembles the color of the sky, such as if it was dyed with istis, black dye, or any other darkening dyes.

Likewise, in Halachah 4[11] he says that if testing establishes that it was dyed with some other darkening dye which does not last, it is possul.

It could therefore come out that if one were to dye with a strong, permanent dye which did not come from a chilazon, it would be kosher for tzitzis.[12] [However, I have not been able to clarify this point. We find in many places that the Rambam gives reasons for halachos which are really gezeiros hakasuv or halachah leMoshe miSinai. It is therefore questionable whether one can derive a practical halachic difference from the reason he gives.]

Nevertheless, from the continuation of the Gemara[13] it seems that dyeing specifically with chilazon blood is required, and not merely because of the durability of the dye. The Gemara says that if the test of Rav Yitzchak the son of Rav Yehudah did not cause the color to fade, it was kosher; if the color did fade, another test was applied, and if it improved under that test, it was kosher.

This is also implied by the straightforward wording of the Tosefta:[14] “Tekhelet is kosher only from the chilazon. If one brought it from something other than the chilazon, it is possul.”

Although the Tosefta is discussing Bigdei Kehunah, there does not seem to be any logical basis to distinguish between them. The Rambam in Hilchos Klei HaMikdash,[15] however, requires further analysis, since he does not mention this condition found in the Tosefta.

The Mishneh LaMelech answers that the Rambam relied on what he had already written in Hilchos Tzitzis, but this is insufficient. Aside from the fact that this itself is somewhat forced, the Rambam’s wording in Hilchos Tzitzis[16] strongly emphasizes that using chilazon blood is specifically a requirement of tzitzis.

Nor does this explain why the Rambam omits another halachah stated in the same Tosefta:[17] “The sheni tola’as must come from the worm of the mountains; if it was brought from something other than the mountain worm it is possul.” Here one cannot say that the Rambam relied on something he explained elsewhere.

R’ Avraham ben HaRambam, however, writes in his commentary on the Torah[18] regarding the Tekhelet of the Mishkan: “Its dyeing is with the blood of the chilazon and not with anything else, as the received tradition explained regarding the Tekhelet of tzitzis.” This requires further study.

Do We Need a Particular Species of Chilazon?

Once we have established that the dye must come from a chilazon, there is still room to ask whether Tekhelet is kosher only from one particular species of chilazon, from any chilazon,[19] or perhaps even from anything resembling a chilazon in some respect.

From the plain wording of the Tosefta cited above, one of two things would appear to be true: either Tekhelet is kosher from anything which falls under the name “chilazon,” or it is in fact kosher only from one particular species, but people happened to use only that particular species for dyeing for some practical reason.[20]

The Source of This Requirement

We must also ask where Chazal derived the rule that Tekhelet may come only from a chilazon.

It is possible that in the language of the Torah, Tekhelet is not merely the name of a color, but specifically means a dye produced from a chilazon. This is somewhat implied by the Gemara cited above,[21] which speaks of “one who hangs kela ilan on his garment and says it is Tekhelet,” and from the Sifrei cited above and similar sources.

The wording of the Rambam in his Peirush HaMishnayos[22] also seems to imply this: not every kind of Tekhelet-colored wool is called Tekhelet, but only a particular known Tekhelet.

On the other hand, the wording of the Tosefta mentioned above seems to imply the reverse — that Tekhelet itself is simply the name of a color. This is also explicit in the Rambam in Hilchos Tzitzis[23] and Hilchos Klei HaMikdash:[24] “The Tekhelet mentioned throughout the Torah is wool dyed like a mixture within blue,” etc.

One can perhaps add the Yerushalmi[25] to the discussion. It asks how we know that Bigdei Kehunah may contain shatnez:[26] “As it says, ‘and the turban of linen… Tekhelet, argaman and tola’as shani…’ Just as sheni tola’as comes from something possessing life, so too everything comes from something possessing life.”

At first glance, the Yerushalmi seems to derive by a hekesh that all of these materials must come from living creatures.

The Pnei Moshe,[27] however, explains it differently. According to him, the Yerushalmi is making a separate derashah from the expression sheni tola’as in the Bigdei Kehunah, meaning that the wool is dyed with the blood of a worm, and extending that principle to anything coming from a living creature and producing a red color similar to the worm.

This is difficult, however, since it does not connect with the previous discussion. Furthermore, how could another dye be kosher when the pasuk explicitly specifies sheni tola’as?

It therefore appears that the Yerushalmi should be understood as follows. It first asks how we know that Bigdei Kehunah may contain shatnez and cites the pasuk,[28] “And the sash of twisted linen, Tekhelet, argaman and tola’as shani.” It establishes that shesh is linen,[29] and then establishes that tola’as shani was dyed onto wool, based on the statement, “Just as sheni tola’as comes from something possessing life…”[30]

It therefore follows incidentally that Tekhelet as well is a dye coming from something alive,[31] although this was not necessarily the Yerushalmi’s explicit intent.

The Bavli, however, derives that Tekhelet is wool from a different source:[32] “How do we know that Tekhelet is wool? Since shesh is linen, Tekhelet is wool.” See Rashi there.

The Yere’im[33] writes:

How do we know that it is dyed with the blood of a chilazon? This follows logically. Tzitzis was commanded as a reminder of the mitzvos, as it says, “You shall see it and remember all the mitzvos of Hashem.” We should therefore say that its color serves as a reminder of the Creator, and that color, by means of one resemblance leading to another, resembles the Kisei HaKavod, as we learned: R’ Yannai said, “Why is Tekhelet different from all other colors? Because Tekhelet resembles the sea,” etc.

This is difficult to understand. Either he holds that a color resembling the sea can only be produced from a chilazon, in which case no sevara is necessary — that is simply the Tekhelet mentioned in the pasuk and there is no other. Or he holds that the same color can be produced from something else, in which case this argument proves nothing.

Perhaps his intention is that Tekhelet should remind us of the sea not only through its color but also through its origin — namely, that it comes from the blood of a chilazon.

Perhaps this is also Rashi’s intent[34] when he explains that Tekhelet resembles the sea: the chilazon comes up from the sea once in seventy years and the appearance of its blood resembles the sea, etc. See there. [See also the Gra, Yahel Or, Pinchas 226b.]

The Chilazon Is an Animal

After all this, we can begin clarifying what a chilazon is.

The chilazon is an animal, as is clear from the fact that on Shabbos one can be liable for trapping it and for taking its life.[35]

The Yerushalmi[36] discusses one who traps a chilazon and breaks it open. One Tanna says he is liable for two melachos, while another says he is liable for only one. According to the first, one liability is for trapping and one for taking a life. According to the second, the liability is for taking a life, but there is no liability for trapping.

The Yerushalmi connects this to the statement of R’ Elazar b’R’ Yosi, R’ Avahu and Reish Lakish in the name of R’ Meir that Hashem created a particular kosher animal for Moshe in the Midbar.

The Korban HaEidah, in his first explanation, writes that there was no melachah of trapping involved with the chilazon, because trapping was not part of the construction of the Mishkan. The chilazon used for Tekhelet certainly was not present in the Midbar, since the chilazon is found only in Eretz Yisrael, in the portion of Zevulun, while Klal Yisrael had Tekhelet from Mitzrayim. Trapping was also not relevant to the rams whose hides were used. Only regarding the tachash could one perhaps say that trapping was involved. But if Hashem created that unique kosher animal specifically for Moshe and it came to him, there was no trapping involved there either.

This is difficult, because it is clear from the Yerushalmi itself that a chilazon was trapped for the work of the Mishkan. It states elsewhere:[37] Chizkiyah said regarding one who kills a louse on Shabbos, etc., and R’ Shimon ben Chalafta responded, “Did we not learn this from the chilazon?” etc.

It is also difficult to say that there is simply no melachah of trapping on Shabbos in this case, since the Mishnah plainly lists trapping as a melachah without dissent.

The correct explanation therefore seems to be the alternative wording in the Korban HaEidah:[38] that one is not liable for trapping the chilazon. Tosafos similarly writes:[39] “The Yerushalmi implies that one who traps a chilazon is not liable משום צידה.”

From the fact that there is an opinion that the melachah of trapping does not apply to the chilazon, it would appear that the chilazon is, to some extent, already “trapped and standing.”

The Chilazon Lives in the Sea

The natural habitat of the chilazon is the sea, as the Sifrei says:[40]

Another explanation of “for they shall draw from the abundance of the seas”: this refers to the Sea of Yafo,[41] which is stored away for the tzaddikim in the future… R’ Yosi said: Once I was walking from Keziv to Tyre and found an old man. I greeted him and asked, “How do you earn your living?” He replied, “From the chilazon.” I asked, “Is it readily found?” He said, “By Heaven, there is a place in the sea lying among the mountains…” etc.

[Although the Gra deletes the word “in the sea” in his hagahos, the entire context itself indicates this, since the story about the chilazon is brought to explain “they shall draw from the abundance of the seas — this is the Sea of Yafo,” etc.]

This is also implied in Menachos:[42] “This is the chilazon… its beriyah resembles a fish,” meaning that it lives in the sea, as apparently understood by the Rambam,[43] who later writes, “the chilazon, which is a fish,” etc.

Even if beriyaso means its physical form or shape, as Rashi and Rabbeinu Gershom explain,[44] the meaning would still be that the chilazon shares some characteristic with fish, since fish as a group do not have one particular shape.

Likewise, the statement that it “comes up once in seventy years”[45] implies that it comes up from the sea, as Rashi explains in Chullin[46] and Sanhedrin.[47] [Rashi in Menachos[48] writes “comes up from the land,” but perhaps the proper reading is “onto the land,” as Rashi writes in Megillah:[49] “the chilazon comes up from the sea to the mountains,” etc.]

Likewise, the Rishonim write in many places that the chilazon’s habitat is the sea.

The Chilazon Is Found in the Mediterranean

The chilazon is found in the Mediterranean Sea,[50] as the Gemara says:[51] “Yogvim refers to the hunters of the chilazon from the ladders of Tyre until Haifa.”

The same emerges from the Sifrei cited above and from Targum Yonasan.[52]

The Rambam likewise writes:[53] “It is found in the Yam HaMelach.” [In the Rambam’s terminology, Yam HaMelach here means the Mediterranean Sea; see his Peirush HaMishnayos to Keilim 15:1 and elsewhere.]

The Zohar,[54] however, says that the chilazon comes up from the Kinneret. In Nitzotzei Or,[55] it is brought in the name of the Ramak that the Zohar is referring to the supernal Kinneret. See there.

A Chilazon of the Mountains

On the other hand, the Gemara[56] tells us that a chilazon can be found in the mountains:

He went up a mountain and saw that today there was only one chilazon there. The next day rain fell, and the entire mountain was filled with chilazonos.

The mefarshim disagree whether this is the same type of chilazon that lives in the sea or a different type.

Rashi[57] writes that it is “a worm which comes out of the sea once in seventy years and whose blood is used to dye Tekhelet. At first only one chilazon is visible on the entire mountain,” etc.

The Yad Ramah,[58] however, disagrees. He writes that this explanation does not appear correct for a number of reasons. First, what would that chilazon be doing on a mountain? If one argues that it was carried up in rainclouds and came down onto the mountain with the rain, then what proof is there from the fact that the next day the whole mountain was full of chilazonos? Perhaps they all came from the sea rather than reproducing from the original one. Furthermore, how can a proof be brought from something which only emerges once in seventy years?

He therefore concludes that the chilazon discussed there is not the chilazon of Tekhelet but another species, “which is generated from earth and water and is called in Arabic chalzum.”

The Aruch[59] also appears to distinguish between them, since he has two separate entries for chilazon: under one he cites our Gemara, and under the other he cites the other Gemaras discussing chilazon.

The Chilazon Has a Shell

The Midrashim also state:[60]

What does it mean that “your garments did not wear out upon you”?… They asked: Did the children not grow, so that their clothing became too small? He answered: Do not wonder. This chilazon — as it grows, its garment[61] grows together with it.

[Now that we have reached this point, we can perhaps explain another Gemara more clearly. The Gemara states:[62]

One who traps a chilazon and breaks it open is liable only once. R’ Yehudah says he is liable twice, because R’ Yehudah holds that breaking open is included in the melachah of threshing. The Chachamim replied that breaking open is not included in threshing. Rava asked: What is the reasoning of the Chachamim? They hold that threshing applies only to things which grow from the ground. But he should also be liable for taking a life!… Rava answers: Even if he broke it open while alive, regarding taking its life he is merely misasek. But Abaye and Rava both say that R’ Shimon agrees regarding a pesik reisha that it will inevitably die? Here it is different, because the longer it remains alive, the better it is for him, so that its dye should remain clear.

We must understand why the Gemara uses the expression “breaking it open,” what connection this has to threshing, and why killing it is regarded merely as misasek.

According to what we have said, however, the Gemara may be referring to breaking the chilazon’s hard shell. Chazal use the language of petziah, breaking open, for nuts as well, and this bears a strong resemblance to threshing. It also becomes easier to understand why killing the animal is merely misasek. See the mefarshim.]

The Chilazon of Chazal Is the Same “Chilazon” We Call a Snail Today

After everything above, it emerges that the chilazon is an animal which exists in the sea, also exists on land, and has a shell.

Among animals that fit these signs, the possibilities are essentially the sea turtle, whose shell grows together with it and which comes onto land to lay its eggs, or the type of animal which today we call a chilazon — a gastropod[63] — and related creatures,[64] some species of which live in the sea and others on land[65].

From the Gemara cited above,[66] which says that chilazonos appear in large numbers after rainfall, we are forced to choose the second possibility. The chilazon of Chazal is the same general creature that we call a chilazon today.

The phenomenon is well known in Eretz Yisrael: during the hot, dry summer, snails enter dormancy; after the first rainfall they appear in large numbers on the surface of the ground.

Targum Yonasan likewise translates the pasuk,[67] “All your trees… the tzelatzal shall possess,” as chilazona. Snails are well known as agricultural pests.

This identification was also known to the Rishonim. In the Rambam’s Peirush HaMishnayos,[68] he explains a chilazon as a shell-like iron object used to lock doors, and explains that this shape is that of the shell of the marine animal called a chilazon. [The original Arabic likewise explains it as a piece of iron shaped like the shell of the sea creature called chilazon.]

The commentary attributed to the Raavad on Sefer Yetzirah[69] likewise says:

Regarding the chilazon, one cannot determine whether it belongs to the category of fish or the category of vegetation. It is alive and moves, yet it does not change its place, because it is planted and fixed in the ground.

The Aruch[70] writes regarding the chilazon mentioned in Keilim, chapter 12, where a ring with a chilazon attached to its end is discussed: “This is its shape. It is called a chilazon because it is shaped like a coiled chilazon.”

The printed editions omitted the illustration, but it remains in several manuscripts. He means a ring made in a spiral resembling the form of the modern snail.

Rashi also uses the Old French limace for a type of chilazon,[71] which refers to the creature we today call a snail. [In Sanhedrin 91a, s.v. chilazon, Rashi calls it a worm.]

The same usage exists in Arabic and Syriac, as the Yad Ramah mentioned in Sanhedrin 91a. See also the commentary attributed to the Ran.[72]

[Everything brought until this point completely disproves the Radzyner Rebbe’s suggestion that the chilazon is a cuttlefish.]

Necessary Premises Before Identifying the Chilazon of Tekhelet

We now have to determine which species among the Mediterranean snails produced the blood used for dyeing the Tekhelet of tzitzis.

Anyone approaching this question must begin with two basic assumptions:

1. We know all the relevant species.
2. No species which existed in the past has disappeared.

Only then is it possible — and necessary — to go through all the known species and select the best fit.

Anyone who does not proceed this way, but simply takes one particular species, decides that it seems suitable, and does not compare it against all the alternatives, is making a serious error in logic.

Another point must be noted. Some statements of Chazal are stated in the form of Aggadah and resemble riddles whose pieces cannot be put together until one understands the underlying purpose clothed within them. The early mefarshim already pointed this out.

I will quote here from the Ramchal’s Maamar Al Aggados Chazal, whose words address the point precisely. He explains that Chazal concealed their teachings in different ways. One method is metaphor and mashal: the literary technique of attributing events or actions to something to which those events do not literally apply. A second method is omission, where necessary conditions are left unstated and a statement is presented absolutely, although it is really true only under a certain condition, from one perspective, at a certain time, regarding a certain subject, or in a particular place.

Anyone who takes such a statement as completely universal and absolute will stumble and become confused. Many statements appear to contradict one another only because their qualifications were not explained; one who knows the boundaries of each statement will find them all true and without contradiction.

The Ramchal further explains that Chazal sometimes hinted at deep secrets by clothing them in matters of nature or astronomy, using the scientific teachings accepted by the scholars of their generation. Their main intention was not necessarily the natural or astronomical claim itself, but the sod which they wished to hint to through it. The truth of the external scientific “garment” does not add to or detract from the truth of the underlying idea, because their intention was to clothe the sod in concepts familiar to the scholars of their generation. One who does not understand this method cannot properly understand their intent.

Now, there is one Beraisa in the Gemara which appears to give simanim for the chilazon whose blood was used for Tekhelet:[73]

The chilazon: its body resembles the sea, its form resembles a fish, it comes up once in seventy years, and with its blood they dye Tekhelet; therefore its value is high.

It is difficult, however, to know precisely what Chazal meant by saying it “comes up once in seventy years.” Did they mean that it is rare, or something else?

Certainly, we should not go hunting for something that literally appears once every seventy years, or approximately seventy years. Chazal use the number seventy years in other Aggadic statements as well.[74] For example, they speak of the gestation of an efeh lasting seventy years and of the carob tree taking seventy years from planting until its fruit matures. Such statements plainly cannot all be read in the simplest literal manner.

Nor must we necessarily infer that Tekhelet was expensive because the chilazon was rare. Perhaps the word “therefore” links the two concepts only in their nimshal rather than in their literal mashal.

Alternatively, perhaps the meaning is simply that Tekhelet is expensive because it is dyed with the blood of this chilazon and this particular chilazon was known as valuable. Or, conversely, because Tekhelet is dyed from it, and Tekhelet itself is expensive, the chilazon is therefore valuable. [This last explanation appears to me the main one.] The statement “it comes up once in seventy years” would then be a separate matter entirely.

Likewise, it is difficult to know exactly what Chazal meant by “its body resembles the sea” to the point that we should make our own understanding of those words the foundation of the zoological search.

In short, we should not take the Beraisa, as we presently understand it, and make that the starting point for the chilazon’s simanim. The opposite approach should be taken: after, with Hashem’s help, we identify the chilazon through logical investigation, perhaps we will then merit to understand something deeper in the words of the Beraisa.

Verifying These Premises

We must now determine whether the two assumptions mentioned above are correct.

According to experts, the second assumption — that no relevant species has disappeared between the period when Tekhelet was dyed and today, a period of approximately fifteen hundred years — is correct.[75]

The reason is that there were no fundamental natural changes in the Mediterranean region during this period and no deliberate extermination of snail species by human beings. According to the normal laws of nature, therefore, an entire species of snail could not simply have disappeared unless through a miracle. [We will discuss the “concealment” of the chilazon below.]

Regarding the first assumption, at first glance it might seem impossible to guarantee that all species occurring along the Mediterranean coast are known today. How can we know that new species will not still be discovered?

Upon closer examination, however, the situation is different. For decades experts have been continually searching for mollusks along the coast and cataloguing the species found there.[76] We can therefore examine whether continued searching in recent years has yielded substantial new species.

The experts’ position[77] is that a small number of new species do continue to turn up, but these are either extremely tiny species barely visible to the naked eye, or isolated individuals which are generally foreign visitors to the area, brought by sea currents, which do not become established and reproduce locally.

We can therefore clearly conclude that for a long period of time, since specialists began systematically searching the Mediterranean coastline, no previously unknown snail species has appeared in quantities substantial enough to have reasonably been used for dyeing textiles.

What Emerges from Examining All Mediterranean Snails

Once these two assumptions have been established, we can examine the known species, reject those wholly unsuitable for dyeing, and focus on those that are suitable.

We first have to clarify what Chazal meant when they said, “with its blood they dye.”[78] Did they mean the animal’s literal blood, or some other secretion?

It is known that the circulatory fluid of mollusks differs in composition from the blood of most other animals. It contains copper rather than iron, with the result that instead of being red like the blood of most animals, it is blue — although generally transparent as well.

According to experts, however, one cannot dye cloth using this blood itself.

Regarding other secretions, five families are known in the Mediterranean region of Eretz Yisrael which possess colored secretions.

Two of them, Scalidae[79] and Mitridae,[80] live at considerable depths and are not practically available for human use.

The Janthinidae[81] family — of which Rav Y. A. Herzog wished to identify Janthina janthina as the chilazon of Tekhelet — lives in the open sea, far from shore, floating on the surface. Only occasionally and irregularly do currents bring it to the coast. It is therefore somewhat difficult to imagine it being a practical resource for human use.

[On the other hand, it fits the Beraisa’s description “comes up once in seventy years” somewhat better. Nevertheless, this species is completely ruled out by the Sifrei:[82] R’ Yosi says that while walking between Keziv and Tyre, he met an old man and asked how he earned his livelihood. The man replied, “From the chilazon.” When asked whether it was readily found, he answered that there was a particular place in the sea among the mountains where it was found. This cannot fit Janthina, which floats on the surface and is washed ashore by the waves, with an equal chance of reaching any part of the coastline rather than being concentrated in one particular location.]

The remaining two families, Muricidae[83] and Aplysia,[84] are found close to shore at certain times and are accessible for human use.

As for the possibility of dyeing with their secretions, according to the experts neither Aplysia[84] nor Janthina[85] produces a secretion suitable for textile dyeing.[86] Only the Murex is suitable for dyeing. It is also very well known from Roman[88] and Greek[89] writings that it was extensively used for dyeing during the period of Chazal.

It therefore emerges from this method of investigation that the chilazon used to dye Tekhelet was the Murex.[87]

Proofs from Our Knowledge of the Ancient World

There are several additional ways to determine which chilazon was used for Tekhelet without depending upon the assumptions discussed above.

First, we possess Greek and Roman works from the time of Chazal[90] whose explicit purpose was to describe the natural world then known and the various uses human beings made of it.

All of these sources prominently describe the dyeing carried out along the coast of Eretz Yisrael using this species, and not one of them mentions a second species being used there for comparable dyeing. [One word in the Hebrew source at this point appears corrupted, but the argument clearly refers to the species under discussion.]

It is extremely difficult to argue that another species was being used for dyeing in those days and somehow escaped all their notice — particularly since the words of Chazal imply that the chilazon itself was well known in the wider world.

The Midrash says:[91] “‘Take from the most celebrated products of the land in your vessels’ — things for which the land is celebrated throughout the world: the chilazon,” etc. Onkelos similarly translates it as “take from that which is praised in the land,” etc.

There are additional forms of evidence of this type which point only to this species. Archaeological excavations[92] have uncovered numerous dyeing installations, and excavations have also uncovered dyed textiles which have been analyzed by experts.

Naturally, the textile evidence is the weakest of these proofs, because not enough garments have been found in enough different places to make a sweeping judgment.

The evidence from dyeing installations is stronger, because workshops give a broader picture of the dyeing actually carried out during the period of Chazal — provided that many dyeing installations were found in many locations.

The strongest evidence, however, is the first: the testimony of people who actually lived in that period and whose purpose in writing was to collect and describe the practices of their own day.

A Proof from the Yerushalmi

Another proof that this species was the chilazon used for Tekhelet comes from a Yerushalmi quoted by the Raavyah:[93]

We learned in the Yerushalmi: “Between Tekhelet and karti — between porpirin and peripinin,” which is called in the foreign language porpira, etc.

[Perhaps Rabbeinu Yonah also had this Yerushalmi in mind; see his commentary to Berachos 9b, s.v. R’ Eliezer.]

This species was called porpira by the Greeks, and dyes produced from it were likewise referred to by that name. [Although one particular reddish shade commonly produced from this chilazon was especially known as porpira, other colors were sometimes also named for their source.]

This passage does not appear in our text of the Yerushalmi, either in the printed editions or in the manuscripts. [Unfortunately, very few manuscripts of the Yerushalmi survive.] We must therefore rely upon the Raavyah’s testimony that this was the text he had before him.

The Ramban’s commentary on the Torah[94] also demonstrates that he understood the matter this way. The Ramban proves that Tekhelet was an expensive material worn only by kings from the fact that in his own time no one would dare wear Tekhelet other than a gentile king[95] — and that ruler is known to have worn porpira.

[Clearly the Ramban was not referring merely to a color. A color by itself proves nothing about expense.]

The same emerges from the Aruch.[96] On the Midrashic expression[97] “the seacoast is the Tekhelet of Bavel,” one of his explanations says that just as a Tekhelet garment is the finest of garments, etc. — and the finest garment known to us is porpira.

The Mekor Chaim[98] says the same. This is also the opinion of R’ Binyamin Mussafia,[99] who writes: “In Greek and Roman terminology, it means a Tekhelet garment.”

See also Avkas Rochel of the Tiferes Yisrael.[100]

Furthermore, whenever Chazal[101] speak of a chilazon that was caught along the Mediterranean coast and from which people earned their livelihood, they refer to it simply as “the chilazon,” without qualification.

It is obvious that the Murex was exceedingly famous in that era and was extensively used by professional dyers in those very locations, as we have seen.

If a completely different chilazon had been used for Tekhelet, how could Chazal speak without qualification of “the chilazon” used along Zevulun’s coast, of the sea granted to Zevulun providing him with the well-known chilazon, and so forth — when these statements are specifically referring to the chilazon of Tekhelet?

The Sifrei says:[102]

“For they shall draw from the abundance of the seas” — this refers to the Sea of Yafo[103]… R’ Yosi said… I asked him, “What is your livelihood?” He replied, “From the chilazon”… “And hidden treasures of the sand” — sefunei refers to the chilazon… The tribe of Zevulun complains before Hashem and says, “Master of the World! To my brothers You gave lands, while to me You gave the chilazon.” Hashem replies, “Through this chilazon I will make them need you…”

All of this refers to the Tekhelet chilazon, as is implied by the statement, “I will make them need you” — meaning through the mitzvah of tzitzis.

[It is difficult to say this refers to the Beis HaMikdash and to argaman, which was required there and was also produced from the Murex, since that cannot properly be described as “I will make them need you.” The Gemara in Megillah[104] likewise says: “They all need you because of the chilazon.”]

Targum Yonasan[105] explicitly explains:

Because they dwell by the shore of the Great Sea, they will support themselves from the tarisa, and they will catch the chilazon and dye from its blood Tekhelet for the threads of their garments…

The Aruch[106] likewise understood the Sifrei this way, placing this Sifrei and the chilazon of Tekhelet together under the same entry. Many Rishonim understood it this way as well.

This is a proof to which there is no answer.

An Additional Proof

A further proof can be added. It is known today from ancient writings[107] and archaeological excavations[108] that wool was dyed with Murex in an actual Tekhelet shade.

The Gemara indicates that there was only one substitute dye which could imitate kosher Tekhelet: kela ilan. It therefore follows that a dye which is not kela ilan and yet produces the same shade is the kosher Tekhelet itself.

The Gemara states:[109] Mar from Mashche brought Tekhelet. They tested it using Rav Yitzchak the son of Rav Yehudah’s test and its appearance faded; under Rav Adda’s test its appearance improved. They thought to declare it possul, but Rav Achai told them: “If so, this is neither Tekhelet nor kela ilan — what, then, is it?” etc.

[This same inference can be made from other places as well.]

What “Blood of the Chilazon” Means

This also helps explain Chazal’s terminology, “the blood of the chilazon.”[110]

How could they call a particular secretion of the chilazon “blood,” when, as explained above, its actual circulatory blood cannot be used for dyeing?

In this particular chilazon, however, the secretion develops a blood-like appearance. The ancients therefore associated it with blood. Yosef ben Mattisyahu[111] likewise writes about this chilazon, from which argaman was dyed, that the color was produced with “the blood of the chilazon.”

Only after boiling it together with additional ingredients does it assume a Tekhelet color.

A Further Point Regarding the Species of Chilazon

Along the coast of Eretz Yisrael there are three species of this family — “family” in scientific terminology:

Murex trunculus,[112]
Thais haemastoma,[113] and
Murex brandaris.[114]

They differ somewhat from one another, and all three were used for dyeing in the period of Chazal.

There is obviously no need to wonder which one alone is “kosher” for Tekhelet. As demonstrated above from the simple wording of the Tosefta,[115] so long as one chilazon possesses no special halachic superiority over another, they all fall under the Tosefta’s category of chilazon and are kosher for Tekhelet.

[In practice, however, the first of the three is the most suitable.]

“Its Body Resembles the Sea”

Now that we have determined the identity of the chilazon used for Tekhelet, we can return to understand the words of Chazal:[116]

The chilazon: its body resembles the sea, its form resembles a fish, it comes up once in seventy years, and with its blood they dye Tekhelet; therefore its value is high.

Regarding “its body resembles the sea,” the Rambam[117] apparently understands this as referring to color. He writes: “Afterward they bring the blood of a chilazon, which is a fish whose appearance resembles the appearance of Tekhelet,”[118] etc.

The Semag[119] says similarly, as does the Sefer HaManhig.[120]

The version in Maseches Tzitzis reads, “Its body resembles the sky.”

Rashi[121] simply comments, “its body — the appearance of its body.” Rabbeinu Gershom Meor HaGolah says the same. Perhaps they too mean its color.

Our chilazon, however, does not have a body color resembling the sea.

One possibility is that “its body resembles the sea” means that its shell is formed with ridges and wrinkles resembling waves, making it look like the sea with its multitude of waves.

Alternatively, it may mean that it clings to the sea floor and does not stand out as a separate object. It becomes almost part of the sea itself, to the point that vegetation and other marine organisms grow upon it. [Particularly since the word yam in the Torah can refer specifically to the seabed, as is known.]

This latter explanation fits the wording of the Beraisa more naturally. According to the Rambam’s explanation, it seemingly should have said, “the color of its body resembles the sea.”

“Its Form Resembles a Fish”

Regarding “its beriyah resembles a fish,” Rashi explains it as “the structure of its form,” while Rabbeinu Gershom says “its shape.”

The Rambam simply calls it a fish. Perhaps all these explanations amount to the same thing: it is an animal that lives in the sea. There is, after all, no one particular shape shared by all fish, and in the language of Chazal anything living in the sea may be termed a dag. See the Gra’s Eliyahu Rabbah.[122]

According to what we explained above, the Beraisa can be understood beautifully as expressing two opposite aspects of the same creature.

On one hand, the chilazon is almost absorbed into the sea itself because it clings to the seabed. On the other hand, it is alive and behaves as a dag — meaning, as a marine animal.

This appears to be the understanding of the commentary attributed to the Raavad on Sefer Yetzirah quoted earlier:

Regarding the chilazon, it is impossible to determine whether it belongs among fish or among vegetation, because it is alive and moves, yet it does not change its place, because it is planted and fixed in the ground.

He apparently connects his description to this Beraisa.

The same is clear from the Rama MiPano,[123] who follows this approach:

The chilazon is inanimate, it is vegetation, and it is alive. We know that it is alive because its body moves back and forth in the place where it grows… It is vegetation because it does not leave its place, but its root is planted and fixed in the seabed… Once in seventy years it is uprooted from there and rises from the water, at which point it is inanimate, without movement, like trees after they have been uprooted. Its rising results merely from the nature and weight of the water, since light objects float upon its surface.

“It Comes Up Once in Seventy Years”

The phrase “it comes up once in seventy years” can be understood in three possible ways:

1. It comes from the sea onto dry land.
2. It rises from the seabed to the surface.
3. It comes up in fishermen’s nets.

The Rambam does not mention this statement at all.

Rashi explains it as the reason for the chilazon’s high price: at other times it cannot be obtained.

The Rama MiPano, however, clearly takes a different approach. According to him, once in seventy years it dies — meaning that seventy years represents its lifespan, just as the Gra explains the seventy years of the carob tree; see the Gra’s commentary on Aggados HaShas, Taanis 23a. At that point it rises.

But once it is dead it can no longer be used for dyeing, since the Gemara[124] makes clear that the dye was extracted while the chilazon was alive.

According to this understanding, the chilazon can be obtained at all times, and its high price must have some other cause.

The Beraisa’s connection between “once in seventy years” and the high price would then exist only on the level of the nimshal rather than the literal mashal.

Alternatively, the Beraisa may mean that Tekhelet itself is expensive. [According to this, the proper reading would be: “Therefore its — Tekhelet’s — value is high.”] Since Tekhelet is dyed with the blood of the chilazon and everyone knows Tekhelet to be an expensive dye, the mitzvah of Tekhelet is costly.

Even according to our present text, “therefore the chilazon’s value is high,” its value could be high because Tekhelet is an expensive dye, not because the chilazon appears only once every seventy years.

This approach of the Rama MiPano to the Beraisa fits our chilazon very well. He understands “comes up” as meaning that it rises from the seabed to the water’s surface. It is somewhat easier, however, to explain it as rising from the sea onto land.

Something Derived from a Non-Kosher Animal for Sacred Use

Now that we have established to our satisfaction what chilazon was used to dye Tekhelet for tzitzis, and apparently for the Mikdash as well, it follows that both the mitzvah of tzitzis and materials used in the Mikdash can involve something derived from a non-kosher animal, since our chilazon has neither fins nor scales.

Even without this identification, however, the point would seem obvious.

Argaman and tola’as shani certainly come from non-kosher creatures.

Argaman comes from our chilazon, as demonstrated by the Septuagint, Yosef ben Mattisyahu,[125] Philo of Alexandria,[126] and other Greek translations, all of which associate it with the mollusk called porpira.

[Even according to the Rambam, who does not say this in his Peirush HaMishnayos to Kilayim 9:1 but says that argaman is a dye called lakh, this too is a known dye produced from the Indian insect Lakshedia lacca, which is a non-kosher living creature.]

Tola’as shani is likewise produced from the well-known insect called Kermes, as indicated by the translations mentioned above, Rav Saadia Gaon’s commentary to Shemos 25:4, the Rambam in Hilchos Parah Adumah 3:2, and many others. This insect is not kosher.

Rabbeinu Bachya,[127] however, writes:

We do not find silk among the donations to the Mishkan because it comes from the body of the sheretz, the worm, and only something kosher was fit for sacred use, as they said regarding the tachash. The dye of tola’as shani does not come from the body of the worm itself, but from berries within which the worm is found…

In reality, however, this is not the case. The red “berries” containing the young insects are themselves the scale insects — their mothers — and these are non-kosher sheratzim.

The Gemara[128] does say that Rav Adda bar Ahavah asked whether the tachash which existed in the days of Moshe was kosher or non-kosher. Rav Yosef replied: “Why is this a question? We learned that only the hide of a kosher animal was fit for meleches Shamayim,” etc. The Gemara asks to what halachah this applies and answers: tefillin.

At first glance, this would seem to establish that only material from a kosher animal may be used for sacred purposes.

One cannot simply say that this requirement applies only to hide, because the Gemara attempted to derive from it that the parshiyos of tefillin must be wrapped with the animal’s hair and sewn with its sinews. The Ran[129] likewise derives from here that a shofar made from the horn of a non-kosher animal is possul.

Nevertheless, the Gemara’s conclusion is that this principle was not stated regarding the Mishkan. On the contrary, the hide of a non-kosher animal would be kosher for the Mishkan, as the Gemara later asks,[130] “What was the conclusion regarding the tachash?” and as the Rashba writes there in the name of Rav Hai Gaon.

Still, it is somewhat difficult to understand how the Gemara could initially have entertained the possibility that only kosher material was fit for the Mishkan.

It appears, however, that Rav Yosef’s Beraisa — “only the hide of a kosher animal was fit for meleches Shamayim” — was specifically discussing hide.

The difficulty from the hair and sinews remains regardless, because the Beraisa explicitly says “the hide of a kosher animal” and the Gemara itself searches for the precise halachah to which this statement applies. The Rashba already raises this difficulty there, as do Tosafos, s.v. lo tzricha.

Rashi resolves it, s.v. ella lenikrachos b’se’aran, by explaining that Rav Yosef’s Beraisa teaches that the parchment sections must be tied with hair from the hide of a kosher animal, etc. See there.

Alternatively, we might say that Rav Yosef’s Beraisa applies to hide and everything analogous to it — hair, sinews, and horns. This would also account for the Ran mentioned above.

The Noda B’Yehudah[131] answers that something used merely for appearance or color has no independent substance. See his lengthy discussion there.

We also find a disagreement between the Rambam and Raavad regarding mor in the Shemen HaMishchah.

The Rambam[132] writes:

Mor is the congealed blood of the animal in India which is well known to everyone…

The Raavad[133] objects:

My mind cannot accept that the blood of any animal in the world should enter into sacred service, and certainly not the blood of a non-kosher animal…

The Raavad does not state the source of his objection.

It is difficult to say that his source is the Gemara in Shabbos mentioned above, because a careful reading of his words indicates that he objects even to the blood of a kosher animal.

It is also difficult to say that his source is the principle of mashkeh Yisrael — min hamutar l’Yisrael,[134] as the Noda B’Yehudah suggested in the responsum mentioned above, because that principle is stated regarding korbanos and libations. This requires further analysis.

Something Derived from a Non-Kosher Animal for Tzitzis

The Magen Avraham[135] writes that all mitzvos are compared to tefillin and therefore something derived from a non-kosher animal is possul.

This is difficult, however, because we find numerous mitzvos which may be fulfilled using materials from non-kosher creatures.[136]

Even regarding tzitzis itself, we find that silk is kosher.[137]

The Ran mentioned above only applied this concept to shofar because he considered it meleches Shamayim, as he writes there. See there.

Many Acharonim also disagree with this ruling.

The “Concealment” of Tekhelet

A number of sources mention the genizah, or concealment, of Tekhelet.

One is Midrash Tanchuma:[138]

The mitzvah is to bring white and Tekhelet and make [tzitzis]. When? When Tekhelet exists.[139] Today we have only white, because Tekhelet has been concealed; therefore the mitzvah is with white.

The Sifrei[140] likewise says:

R’ Yosi said: Once I was walking from Keziv to Tyre and found an old man. I greeted him and asked, “How do you earn your living?” He answered, “From the chilazon.” I asked, “Is it readily found?” He replied, “By Heaven, there is a place in the sea lying among the mountains, and poisonous creatures bite it, and it dies and decomposes where it lies.” I said, “By Heaven, it is apparent that it is concealed for the tzaddikim for Olam HaBa.”

The Gemara likewise relates:[141]

R’ Yochanan said: Once we were travelling by ship and saw a certain basket… A bas kol came out and said to us: “What business do you have with the basket of the wife of R’ Chanina ben Dosa, in which she will place Tekhelet for the tzaddikim in the World to Come?”

There is no necessity whatsoever to understand the “concealment” mentioned in these sources as a miraculous disappearance of the chilazon. It may simply mean that for some reason people stopped dyeing with it.

More than that: it is not even necessary to understand that people stopped using the chilazon altogether. It may mean only that such dyeing was no longer commonly available. [We find similar language concerning the disappearance of white glass; see Bava Metzia 29b, Tosafos s.v. bizchuchis levanah.]

Certainly one cannot derive from this any halachah prohibiting the wearing of Tekhelet nowadays and thereby cancel an entire mitzvah from the Torah.

Consider that throughout the Talmud, until the period of Rav Achai,[142] the dyeing of Tekhelet is mentioned as a normal, practical reality.

We also do not know when the statements about the concealment of Tekhelet in Midrash Tanchuma were composed.

The “concealment” mentioned in the Sifrei and in Bava Basra is an entirely different matter, as is evident to anyone who examines those passages carefully.

Those sources are not speaking about the cessation of Tekhelet at all.

In the Sifrei, R’ Yosi is speaking with an old man who makes his livelihood from the chilazon. From the difficulty involved in finding the chilazon, R’ Yosi concludes[143] that the deeper matter of Tekhelet hinted at in the story is “concealed for the tzaddikim for Olam HaBa.”

The passage in Bava Basra similarly refers to a future spiritual matter. This is not the place to elaborate.

On the contrary, it is historically known[144] that the famous Murex dyeing industry which existed along the shores of Eretz Yisrael ceased at approximately the time of the Arab conquest — roughly around the period of the final sealing of the Bavli. This explains how Tekhelet disappeared from Klal Yisrael.

As for the statements of the mekubalim concerning the concealment of Tekhelet, these do not have halachic relevance whatsoever, in accordance with the guidance of the Vilna Gaon zt”l.[145]

[This is clear from the sources themselves. Pri Etz Chaim, for example, speaks of Tekhelet as having been concealed from the time of the Churban, while in the period of the Gemara the mitzvah of Tekhelet was certainly still being practiced.]

The Color of Tekhelet

We must now clarify which shade is called Tekhelet.

At first glance, the Gemara itself seems to define the color. It states:[146]

R’ Meir said: Why is Tekhelet different from all other colors? Because Tekhelet resembles the sea, the sea resembles the sky, and the sky resembles the Kisei HaKavod, as it says, “Under His feet was like the work of a sapphire brick, and like the essence of the heavens for purity,” and it says, “Like the appearance of a sapphire stone, the likeness of a throne.”

One might still ask whether Chazal meant a precise resemblance or only a general similarity.

But we must understand why R’ Meir begins with the sea and only afterward moves to the sky. He could simply have said that Tekhelet resembles the sky.

It is understandable that he could not compare Tekhelet directly to the Kisei HaKavod, whose color is unknown, nor necessarily to sapphire, because not all such stones have an identical appearance.

Rashi[147] explains:

All these stages were necessary because the pesukim only tell us that the sky resembles the Kisei HaKavod. Therefore Tekhelet resembles the sea and the sea resembles the sky, because Tekhelet does not resemble the sky quite as closely. Rather, one resemblance leads to another: Tekhelet resembles the appearance of the sea, and we ourselves see that the sea resembles the appearance of the sky.

[Rashi requires explanation. If Tekhelet resembles the sea exactly but does not resemble the sky exactly, then presumably the sea does not resemble the sky exactly either. Why is it better to compare the sea to the sky rather than Tekhelet itself to the sky?

The answer may be that the sea and sky are always visibly adjacent in the eyes of every observer.]

From this it would appear that Tekhelet’s resemblance to the sea is a full resemblance.

The Pesikta Rabbasi[148] says this explicitly:

As soon as Moshe ascended on High, HaKadosh Baruch Hu opened the seven heavens… and showed him the four colors with which the Mishkan was made… Moshe said before Him: “Master of the World, I do not know the appearance of these four colors.” He told him, “Turn around.” He turned and saw a troop of malachim wearing garments resembling the sea. He said to him, “This is Tekhelet,” etc.

Nevertheless, the proof from the Gemara can perhaps be rejected. There may be other reasons for associating Tekhelet with the sea — either because it recalls the miracles Hashem performed for Klal Yisrael at the sea, or because the chilazon itself comes from the sea, as seems to be implied by Rashi in Menachos[149] and Chullin.[150] See there.

Additional Proofs Regarding the Color of Tekhelet

A major proof can be brought from the Sifrei:[151]

R’ Elazar b’R’ Shimon says: Why is it called Tekhelet? Because the Egyptians were nis’kalu — destroyed — through the firstborn, as it says, “At midnight Hashem struck every firstborn.” Another explanation: because the Egyptians were destroyed at the sea.

It is explicit here that the color of the nighttime sky is Tekhelet and that the color of the sea is Tekhelet.

[This does not rule out the possibility that nearby shades may also be called Tekhelet. We do not know whether Tekhelet describes a broad range of similar shades or one very specific shade. In any event, these shades are unquestionably included.]

R’ Moshe HaDarshan[152] likewise explains:

“A thread of Tekhelet” — because of the bereavement of the firstborn. The Aramaic translation of shechol is tikla, and their plague took place at night. Similarly, the color of Tekhelet resembles the color of the sky as it darkens toward evening.

I have another proof from the Gemara:[153]

The clasps in the loops appeared like stars in the sky.

Meaning specifically the loops, which were Tekhelet, resembled the sky at the time stars become visible.

This is also supported by Philo of Alexandria,[154] who lived during the period of the Beis HaMikdash. He speaks of the Tekhelet in the Mikdash as resembling the sky and remarks parenthetically that the heavens are by nature dark.

[Perhaps this can explain R’ Meir’s statement that “Tekhelet resembles the sea and the sea resembles the sky.” The sea is known to be dark blue. The true color of the sky, however, is not known to us; it appears light blue to us. But since the sky consists of the upper waters, its real color is like the sea — meaning dark blue — and it appears light to us only because of distance and the abundance of light.]

The Ibn Ezra[155] cites a similar explanation in the name of Yefes and disagrees with him. [It seems to me that the Ibn Ezra understood him as meaning literally black, and therefore disagreed and called Tekhelet yarok,[156] i.e. our blue. Rashi, after all, cites the words of R’ Moshe HaDarshan above without disagreeing and himself calls Tekhelet yarok.]

The commentary attributed to the Rokeach[157] likewise implies this:

Tekhelet is wool dyed close to blackness, resembling the sky at its furthest depth; therefore it is called Tekhelet.

Something similar is implied by the Ramban:[158]

This color is the tachlis, the endpoint, of all appearances, because at a great distance all things appear in that color, and therefore it is called Tekhelet.

The Rambam’s Opinion on This

The Rambam,[159] however, writes:

The Tekhelet mentioned throughout the Torah is wool dyed like a mixture within blue, and this is the appearance of the sky seen by the eye in the clear light of day.

The term pasuch is used in Mishnah Negaim 1:2. There the Rambam explains that pasuch is an appearance mixed from white and red, etc.

The Rambam therefore goes out of his way to explain that Tekhelet is specifically a lighter blue.

[Although the Rambam there calls colors resembling Tekhelet mashchirin, “darkening colors,” he uses that expression generally for substances which produce blue, as is also apparent from Moreh Nevuchim, part 1, in the tenth introductory premise regarding the Mutakallimun.]

R’ Avraham ben HaRambam[160] says this explicitly as well:

Tekhelet is dyed wool whose appearance resembles what is seen of the sky — a pure blue, an intermediate shade between deep blue and white.

[However, see HaMaspik LeOvdei Hashem,[161] where Tekhelet is described as pure blue wool resembling the color of the cloud as it appears to the eye, which is the color of the sky.]

The Rambam’s view can perhaps be supported by the Midrash Rabbah:[162]

Therefore the garment above was Tekhelet, with its face toward the sky which resembles it…

Rav Saadia Gaon likewise writes in his commentary on the Torah:[163] that the celestial spheres beneath them, etc., as in the pasuk “Who stretches out the heavens like a curtain,” delight the eyes of men through the color of Tekhelet, the same color from which the Mishkan was made.

In his commentary on Sefer Yetzirah[164] he similarly writes:

The roof of the Mishkan resembles the sky because it contains a woven material of the colors of the heavens, samaan jun,[165] which is called Tekhelet.

The Baal HaIttur[166] cites Rav Nachshon Gaon that Tekhelet is the color lawn asma,[167] meaning “the color of the sky.”

Yosef ben Mattisyahu,[168] who lived during the period of the Beis HaMikdash, writes similarly.

It is possible, however, that these statements were not intended to exclude darker shades. They establish that the sky may be called Tekhelet, but perhaps a deeper blue is Tekhelet as well, with Tekhelet being a broader color category. This indeed appears to be the meaning of many Rishonim,[169] who treat Tekhelet as a general category of blues.

Another Way to Determine the Color

There is another method for determining the shade called Tekhelet: its complete resemblance to kela ilan, to the point that the two could not be distinguished without special chemical tests, as explained above.

One should not suggest that counterfeit Tekhelet was made from kela ilan mixed with another dye.

The Sifrei[170] says:

Why is Yetzias Mitzrayim mentioned here? So that a person should not say, “I will put other dyes and kela ilan, which resemble Tekhelet, and who will know?”

At first glance, this might sound like a mixture.

But the Sifrei’s intent is “other dyes or kela ilan.”

The straightforward meaning of the Gemara throughout is that Tekhelet was counterfeited with kela ilan alone.

This is also demonstrated by the Gemara:[171]

A tallis which is entirely Tekhelet-colored — all other colored strings may exempt it except kela ilan.

The concern is either that someone may confuse kela ilan with real Tekhelet, or that the Tekhelet string will not be visibly distinct, since the Torah requires two appearances.

That discussion is not about a counterfeiter trying to create a special mixture imitating Tekhelet. It concerns a person who simply happens to dye his garment with kela ilan.

If we can therefore identify kela ilan, we can determine the color of Tekhelet.

The Aruch[172] identifies kela ilan as indigo,[173] as does a responsum of Rav Amram Gaon.[174]

The same is implied by the Tosefta:[175] “Kela ilan which was threshed[176] with wood from an asheirah must be burned,” etc., since indigo was manufactured by pounding or threshing leaves that had been soaked in water.

This method, however, does not enable us to determine precisely how light or dark the Tekhelet was.

See also Rabbeinu Yonah,[177] who writes:

Regarding karti, some explain that it is related to grass and onions, which are translated as karti and betzli. This does not appear correct, for what connection would Tekhelet have to karti? Rather, the correct explanation is certainly that of R’ Nosson, the author of the Aruch [this does not appear in our Aruch], that karti is a type of dye called hindi which resembles Tekhelet. Therefore Chazal spoke of one who can distinguish between the two…

Tosafos[178] says something similar with minor variation. See also Tosafos elsewhere,[179] from which it appears that there is some difference between Tekhelet and indigo.

One further point may be added. Excavations at Dura Europos in Syria[180] uncovered an ancient synagogue from the period of the Tannaim containing wall paintings of Biblical scenes. In one painting Aharon HaKohen is depicted,[181] wearing a Tekhelet garment[182] — and it is blue.

The Opinion of the Zohar and the Mekubalim

In the Zohar, Tekhelet is described as the color of the sea,[183] and in many places as the blue color at the base of a candle flame.[184] It is also described as a dark color[185] and as the culmination of all colors.[186]

The Ramak in Pardes[187] writes in the name of the mekubalim that Tekhelet—

[The source text breaks off here.]

The Color of Tekhelet in the Greek Sources

All the ancient Greek translations[188] use the same translation for the word Tekhelet.

The same is found in Esther Rabbah:[189]

“Chur, karpas and Tekhelet” — Aquila translated it airinon karpasinon, while R’ Bibi said teynon.

See the Aruch,[190] who has the reading yakinthinon as the Greek translation of Tekhelet. This is in fact the Greek term used in all the translations mentioned above.

It is, however, extremely difficult to determine from this Greek word the exact shade it was intended to describe.

At times the word refers to a particular flower of that color or to a precious stone of that color. It is very difficult to determine precisely which flower or which stone was intended, and linguistic experts disagree about it.

We are therefore left with the words of Chazal themselves, from which the color of Tekhelet emerges quite clearly.

Blessed is the Merciful One Who assisted us.