Tag Archives: Indigo

What is Tekhelet?

At the beginning of this week’s parasha, Tetzave, the Torah describes the special garments worn by the Kohanim. Making these garments requires the use of three unique dyed fabrics: tekhelet, argaman, v’tola’at shani, “blue, purple, and crimson wool”. Last year, we discussed tola’at shani and the practice of wearing a red string on the wrist. This year we will explore the other two ingredients: tekhelet and argaman. What are they and where do they come from?

In Greek mythology, the hero Hercules discovered Tyrian purple when his dog chewed on sea snails, as depicted here in Peter Paul Rubens’ “Hercules’ Dog Discovers Purple Dye”

Argaman is more commonly known as “Tyrian purple” or “royal purple”, a famous and prized dye in ancient times. Historical records and archaeological findings show that as early as 3500 years ago, trade in Tyrian purple was widespread across the Mediterranean and the Middle East. It was the Phoenicians who were experts in its production, and carried it around the region. (In fact, the root of the term Phoenician means “purple” in Greek. Similarly, some scholars have found evidence that Canaan means “dye merchant”.) Tyrian purple was worth at least as much as silver, and in some points in history, more than gold.

By the Roman Era, it was so expensive and prized that it was essentially only worn by royalty, hence “royal purple”. An average Roman, or even a Roman senator, would wear a toga pura, plain white, while magistrates and priests wore a toga praetexta, with a purple stripe or hem. Only the emperor would wear a toga picta, one that was entirely dyed purple, with gold embroidery. (Such a toga might also be worn by high ranking generals during their victory processions, as well as by the consuls.)

Shells of the Murex snails that produce purple and blue dye. (Credit: U.Name.Me)

How did the Phoenicians produce argaman? It was extracted from the glands of shellfish on the Phoenician shores of the Eastern Mediterranean. These Murex snails make the dye as a defense mechanism, spraying it on potential predators (just as squids and octopuses, their mollusc relatives, famously do). Research shows that the snails also use the dye for their own predatory behaviour when catching prey, and also as an antimicrobial to protect their eggs. To extract the dye, the snails are either “milked”, which takes a very long time, or more commonly, pierced through their shells to have the glands removed. It would take over 10,000 snails to produce just a few grams of dye!

Tekhelet was made the same way. Though not nearly as popular in ancient times, it was known as “royal blue”. The Phoenicians made it the same way, extracted from a snail. Some say it was derived from a different species of snail, while others point out that the same Tyrian purple, when exposed to large amounts of UV radiation (sunlight), becomes blue.

The Talmud (Menachot 44a) states that the dye was made from chilazon, a snail “whose body resembles the sea, and its form resembles a fish, and it comes up once in seventy years, and with its blood one dyes tekhelet, and therefore its blood is expensive.” It’s not quite the blood of the snail that makes the dye, of course, nor do the snails emerge only once in seventy years. This bit probably entered the Talmud because by that point in history, tekhelet production among Jews had long ended, and knowledge of its exact extraction forgotten. It was probably difficult, if not entirely impossible, for Jews to get their hands on it.

Tzitzit with tekhelet (Credit: Tekhelet.com)

Dr. Baruch Sterman, in a paper for B’Or HaTorah (vol. 11, pg. 185), points out that by the 4th century CE it was actually a crime for a commoner to wear tekhelet across the Roman world. It is highly likely that it was then, for this reason, that most Jews stopped using tekhelet in their tzitzit. Dr. Sterman brings proof from the Talmud (Sanhedrin 12a), where we read how two rabbis were arrested by the Romans for possessing tekhelet. Wealthy Jews living in the Persian Empire continued to pay exorbitant rates to import and use it, until sometime in the middle of the 7th century. It was then, likely due to the rise of Islam and the rapid Arab conquest of the region, that use of tekhelet among all Jews essentially ceased. This is why until today the majority of Jews do not use tekhelet in their tzitzit (as the Torah commands). However, in recent decades, the Murex snails have been rediscovered, and tekhelet is once again available.

Having said all that, Karaite Jews—a small group that rejects the Talmud—believe that tekhelet (and argaman) could not have been derived from snails. And they actually have a couple of seemingly valid points.

The Problem of Karaite Tekhelet

The Karaites believe that tekhelet cannot come from a snail because the Torah would not command something so important to come from a non-kosher animal. They also argue that royal blue tekhelet from snails would have been far too expensive for the average Israelite. Finally, they point out that God commanded this to the Israelites in the Wilderness—so where would they find sea snails in the middle of the desert? Instead, Karaite scholars proposed that tekhelet came from an indigo plant, such as the Indian Indigofera tinctoria (incidentally, this is the indigo once used to dye jeans blue).

Another, more likely, possibility is the woad plant, Isatis tinctoria, which contains the same indigo dye. This plant actually grows in Israel, and was once known as “Asp of Jerusalem”. Interestingly, the Mishnah (Megillah 4:7) states how Kohanim are forbidden from blessing the congregation if their hands are stained with “istis”, ie. the Isatis tinctoria dye. The Bartenura (Rabbi Ovadiah of Bartenura, c. 1445-1515) confirms that istis is a dye “whose colour resembles tekhelet”. This makes it clear that Kohanim in the ancient Holy Temple did use woad as a blue dye, though for what purpose is unclear.

Karaite Jews today continue to make tekhelet from indigo or woad to dye their tzitzit. Since Karaites hold strictly to the Written Torah, they maintain that tzitzit must be blue (and cannot be entirely white like most current “Rabbinic” tzitzit). They hold that any blue dye is fine, since the Torah does not explicitly say that other blue dyes are forbidden. The Talmud, meanwhile, states that a person who uses plant-derived blue dyes instead of authentic tekhelet is sinning, and God declares that He will “exact retribution” from such a person (Bava Metzia 61b, see also Tosefta on Menachot 9:6). And here the Karaites should take heed, for when it comes to tekhelet they are absolutely mistaken.

The big problem for the Karaites is basically everyone else. Aristotle (384-322 BCE) wrote in his History of Animals about the production of blue and purple dyes from snails, as did the Roman philosopher and historian Pliny the Elder (23-79 CE) in his Natural History. These were the choicest and best dyes for clothes and fabrics. While tekhelet and argaman were expensive for the distant Greeks and Romans to procure, they would not have been expensive for the ancient Israelites. After all, these dyes were only expensive to purchase; there is no indication that they were expensive to produce. And the Israelites, like the Phoenicians and Canaanites, were the producers. They made the dyes cheaply, and exported them far and wide, for a healthy profit.

It was only in later centuries, when Israel was no longer an independent entity and was subject to a series of foreign empires, that Jews lost control of the means of tekhelet production. Tekhelet became rarer, and more expensive, and eventually forbidden. This development only occurred in the late Second Temple era, and possibly later. Still, when chemists in the 1990s analyzed blue fabrics uncovered at the Masada archaeological site, they discovered that the fabrics were indeed dyed with Murex snail tekhelet. Even in the late Second Temple era, tekhelet was available and used widely. Besides, the average Israelite in those days would have needed only a minute amount to dye a handful of strings to fulfil the mitzvah of tzitzit.

Another bit of evidence for the fact that snail dye was the real tekhelet comes from the Tanakh itself. While we’ve already seen how historical and archaeological records make it clear that the ancient Phoenicians were experts in snail dyes (not any plant-based blue dyes), we mustn’t forget that these same Phoenicians were heavily involved in the production of Israelite holy items, too! We read in the haftarah for last week’s parasha (I Kings 5:26-6:13) how King Solomon made an agreement with the Phoenician King Hiram, and the latter’s workers played an instrumental role in the construction of the Holy Temple. Granted, this was not the Mishkan of the Wilderness, but the later Temple was based on the earlier Mishkan, and the items were fashioned to the same specifications.

Where was Hiram’s capital city? The Tanakh always refers to him as melekh tzor, “King of Tyre”. This is the selfsame Tyre as the Tyre of Tyrian purple and Tyrian royal blue. We read how “Hiram, king of Tyre, sent his servants to Solomon…” (I Kings 5:15) It is hard to believe that it’s only a coincidence that the Tyrians renowned around the ancient world for their snail dyes are the same ones that the Tanakh tells us worked in Jerusalem! The evidence is therefore quite strong that tekhelet and argaman are the same as the snail-derived Tyrian dyes.

Tekhelet in the Wilderness

The nail on the coffin comes from an even more ancient historical text. Long before Pliny, Aristotle, and even Hiram, the ancient Egyptian Papyrus Anastasi I—dated back to the Nineteenth Dynasty (c. 1292-1189 BCE)—mentions how a royal blue dye is made from sea creatures and smells like putrid fish. This is particularly important because the Nineteenth Dynasty was the time of Pharaoh Ramses II, who is the one most associated with the Exodus. Ramses II built a new capital city which, of course, he named after himself, and which archaeologists have uncovered and refer to as Pi-Ramesses. This is the same city that the Torah mentions the Israelite slaves built (Exodus 1:11). Putting the pieces together, we now have an answer to the question posed by the Karaites: how did the Israelites find tekhelet and argaman in the Wilderness?

The Torah tells us that when the Israelites left Egypt, God commanded them to ask the Egyptians to give them precious materials: “And the children of Israel did according to the word of Moses, and they asked of the Egyptians jewels of silver, and jewels of gold, and raiment.” (Exodus 12:35) The Israelites got tekhelet and argaman from the same place they got their gold and silver (also used in constructing the Mishkan): from the Egyptians. The Papyrus of Anastasi proves that the ancient Egyptians, too, produced blue and purple dyes from Mediterranean snails. They made “raiment”, garments and fabrics dyed with these colours. The Torah informs us that the Israelites took these fabrics with them. And this is how they had them available for the Mishkan in the Wilderness!

Despite all that’s been said, the Orthodox world today has been very slow in readapting the use of tekhelet. Some rabbis maintain that these Murex snails are not the right ones. The Radziner Rebbe (Rabbi Gershon Henoch Leiner, 1839–1891) didn’t know about the snails at all and instead consulted chemists to produce a blue dye from the common cuttlefish, Sepia officinalis. The problem is that the cuttlefish only produces black ink, and turning it blue was a long chemical process that required adding iron filings. When later analyzed by experts, it was found that the Radziner Rebbe’s dye was basically synthetic, and the blue was simply a result of the added iron. (For more, see Dr. Sterman’s article in B’Or haTorah, cited above.) Meanwhile, Rabbi Isaac Herzog (1888-1959, Israel’s first Ashkenazi Chief Rabbi) was an early proponent of snail-derived dyes.

In recent decades, more and more researchers have explored the subject, and today everything points to tekhelet being the blue dye of the Murex trunculus snail. The scientists at Masada confirmed it chemically, and although some state that there is no chemical difference between woad, indigo, and Murex blue, there are small differences in their molecular structure. One with a chemistry background will agree that the addition of even a single atom can dramatically change the nature of a substance. Still, many rabbis are reluctant to adopt tekhelet, and have decided it is best to wait until Mashiach comes just to be sure.

Comparing the chemistry of blue dyes: though looking similar to the untrained eye, the chemical structure of plant-based Indigotin (top left) is different from synthetic indigo (bottom left) and the indigo of Murex snails (bottom right).

And as for the Karaite argument that the Torah wouldn’t command something derived from a non-kosher animal, this argument falls apart when considering the third ingredient that always goes along with tekhelet and argaman: tola’at shani. The word is literally translated as a “crimson worm” or, more accurately, “red insect”. Tola’at definitely refers to a bug of some sort, as we read in Exodus 16:20 how leftover manna was infested with tola’im.

Tola’at shani is undoubtedly referring to the common carmine dye used around the world, and known commercially in food as E120. This dye is derived from a variety of scale insects, most commonly the cochineal family of bugs. Professor Zohar Amar of Bar Ilan University spent many years researching tola’at shani and concluded that it is unquestionably a red insect, which nests in the common Israeli oak tree. In fact, the Temple Institute has already begun harvesting these insects to produce an authentic avnet, the priestly belt that requires the red dye, in preparation for Mashiach’s coming and the return of priestly service in the forthcoming Third Temple.

Clockwise from top left: Professor Amar leads the Temple Institute’s Tola’at Shani harvest; the “crimson worm” on a branch of an Israeli oak tree; Professor Amar holds a cup of crimson water produced by crushing a single worm.


The above essay is adapted from Garments of Light, Volume Three.
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