One should always be heedful of the commandment to wear tsitsit,
for the Torah equated and connected all other mitzvot with it,
as it is written 'And you shall see it and remember all of the commandments
of Hashem and you shall do them.'
(Rambam, Hil. Tsitsit, 3;13)
The story of the search for the source for the dye
tekhelet - Biblical blue - is one of intrigue, deception, and
deduction. It weaves together clues from Torah scholarship, archeology, and
chemistry, and its major players include a great Chasidic Rebbe, a former
Chief Rabbi of Israel, archeologists, marine biologists and chemists.
"And the Rabbis said: Why does the Torah enjoin us regarding tekhelet?
Because tekhelet resembles sapphire, and the Tablets were of sapphire, to
tell you that so long as the people of Yisrael gaze upon this tekhelet they
are reminded of that which is inscribed on the Tablets and they fulfill it,
and so it is written, 'And you shall see it and remember.'
(Mishnat Rabbi Eliezer, ch. 14).
In ancient times purple and blue dyes derived from snails were so rare
and sought after that they were literally worth their weight in gold.
These precious dyes colored the robes of the kings and princes of Media,
Babylon, Egypt, Greece and Rome. To wear them was to be identified with
Twice daily we read:
"Hashem spoke to Moshe saying: Speak to the Children of Israel
and say to them that they shall make themselves tsitsit on the
corners of their garments throughout their generations.
And they shall place upon the tsitsit of each corner a thread of
tekhelet... And you shall see it and remember all of the commandments of
Hashem and you shall do them,"
We are commanded to place a thread of blue on our tsitsit as
a constant and conspicuous reminder of our stature. We are
noble sons of the King of the Universe, always pursuing His
"And now we have only white, for the tekhelet has been hidden."
(Bemidbar Raba 17:5)
The Mediterranean coast was the center of the dyeing industry in the
ancient world. "Tyrian Purple" came from the port of Tyre in Phoenicia
(now southern Lebanon). The Phoenicians made their wealth trading in the
dyestuff, and dye houses were ubiquitous in the region. Because of its
lucrative nature, purple and blue dyeing slowly came under imperial control.
The Romans issued edicts that only royalty could wear garments colored with
these dyes, and only imperial dye houses were permitted to manufacture it.
This apparently drove the Jewish
tekhelet industry underground. Later, with
the Arab conquest of
Eretz Yisrael (683 CE), the secret of
essentially lost, the dyeing process forgotten.
A coin from the city of Tyre
dated 200 C.E. depicts the legend of
Hercules' dog discovering the Murex.
"Rabbi Meir said: Whoever observes the mitzva of tsitsit, is considered as
if he greeted the Divine Presence, for tekhelet resembles the sea, and the
sea resembles the sky, and the sky resembles God's holy throne."
(Sifre, Shelach, 15:39)
The Biblical commandment to wear
tsitsit is still observed today,
but the prominent blue thread has all but been forgotten. What has
remained are passages in the Talmud describing the source of the blue dye -
a snail known as the
Chilazon. This marine creature had a shell, could be
found along the northern coast of Israel, and its body was
"similar to the sea." The dye's color was "similar to the sky
and sea," it was steadfast, extracted from the snail while still
alive, and was indistinguishable from a dye of vegetable origin,
called kala ilan (indigo).
"There is an obligation, upon all who are capable, to search for
it [the Chilazon], in order to bring merit upon Israel with this
commandment, which has been forgotten for the last several centuries.
And he who succeeds in this will surely be
blessed by the God of Israel."
(Rabbi Gershon Henoch Leiner, the Radzyner Rebbe)
In 1858 the French zoologist Henri de Lacaze-Duthiers found that three
Mediterranean mollusks produced purple-blue dyes. One,
was determined by him (and other scientists, archeologists and historians)
to be the source of the ancient Biblical blue.
In the same century, unaware of Lacaze-Duthier's findings,
Rabbi Gershon Henoch Leiner - the Radzyner Rebbe - set out on an
expedition to search for the lost
Chilazon in a grand effort to restore
tekhelet to the Jewish people. He was convinced that a certain
squid fit the descriptions of the
Chilazon. However, unable to produce a blue dye from the black
ink released from this squid, he turned to an Italian chemist, who provided
him with a method. Within two years, ten thousand of the Rebbe's followers
were wearing blue threads on their
tsitsit. The Rebbe published two books
to counter the strong opposition from other Torah scholars who did not
agree with the Rebbe's conclusions.
"The [squid] blood ... is mixed with iron filings and a snow white
chemical called potash. After keeping it on a large powerful fire for some
four or five hours, until the flames burn outside and inside as the fires
of Gehenna, the mixture fuses..."
(from a letter sent by the Radzyner dye master to Rabbi Herzog)
In 1913 the Chief Rabbi of Ireland, Rabbi Isaac Herzog
(later Chief Rabbi of Israel), wrote a doctoral dissertation on the
subject of Hebrew Porphyrology (the study of purple - a word he coined).
When he sent samples of the Radzyn
tekhelet to chemists and dye experts
for analysis, the dye was found to be inorganic - a synthetically
manufactured color known as Prussian Blue. Refusing to believe that
Rav Gershon Henoch had purposely misled his constituents, Rav Herzog
studied the Radzyner dyeing process. The truth soon became apparent.
The process called for subjecting the squid ink to intense heat and then
adding colorless iron filings to the mixture. This produced the blue color
which indeed appeared to come from the squid ink. In fact, under these
conditions, virtually all organic substances would yield the same blue
dye - the squid was not an essential component. The Rebbe had apparently
been misled by an unscrupulous chemist.
As an interesting side note of history, during World War II
with the destruction of East European Jewry, the
tekhelet factories of
Radzyn were ruined and the process lost. When the survivors of Radzyn
made their way to Israel after the war, they asked Rav Herzog for the
correspondence between himself and the Radzyn dye makers, and through
those letters reestablished a
tekhelet industry in Israel which still
flourishes to this day. Thus Rav Herzog is responsible both for discrediting
tekhelet and at the same time for rescuing their process from
The vein is removed... and to this salt has to be added...
three days is the proper time for it to be steeped, and it should be
heated in a leaden pot with 50 lbs. of dye to every six gallons
(Pliny the Elder, Natural History 9.61.133, first century BCE)
Rav Herzog knew of the work done by Lacaze-Duthiers and others, and
realized that all the evidence pointed to
Murex trunculus as the most
likely candidate for the
tekhelet source. Two problems, however, prevented
Rav Herzog from positively identifying that snail with the
Chilazon. First, the dye obtained from the
trunculus was purplish-blue, not pure blue as tradition maintained.
Second, this snail has an off-white shell with stripes of brown, hardly
fitting the Talmudic description of the
Chilazon as appearing similar to
Current research has supplied the solutions to these objections.
The shell appears off-white with brown stripes when it is out of the water,
cleaned and polished. In its natural element, however, trunculus is covered
with a coat of sea fouling the color of the ocean. Everything in its
vicinity is covered with the same fouling, making it almost impossible to
distinguish the snail from the sea bed on which it is found. The Talmud's
description is of the
Chilazon in its natural habitat!
The riddle of producing a pure blue color from the snail was
serendipitously solved. While researching the methods used by the ancient
dyers, Prof. Otto Elsner, of the Shenkar College of Fibers, noticed that
on cloudy days, trunculus dye tended towards purple, but on sunny
was a brilliant blue! He found that at a certain stage of the
dyeing process, exposure to sunlight will alter the dye, changing
its color from purple to blue. To the dye masters of old, working in the
bright Mediterranean sunlight, this was certainly no secret.
The Chemistry of Tekhelet
Inside the hypobranchial gland of the snail, the precursors to
the dye exist as a clear liquid. When these are exposed to air
and sunlight in the presence of the enzyme purpurase, which also
exists within the gland, they turn into the dye. Purpurase quickly
decomposes, so for this reaction to take place, the gland must be
crushed soon after being taken from the live snail, in accordance
with the Talmudic passage that the
tekhelet is taken from the
Chilazon while still alive. The liquid from the
trunculus, produces a mixture of dibromoindigo (purple) and indigo.
These molecules must be put into solution for them to bind tightly to wool.
In this state, if dibromoindigo is exposed to ultraviolet light, it will
transform to indigo, turning the trunculus mixture from purplish-blue to
"Have mercy on us and rebuild Your city speedily in our days, and
bring us to peace, to our Holy Land, and let us merit the return
and revelation of the Chilazon, that we may be privileged to fulfill
the commandment of tekhelet in tsitsit."
(from the prayers of Rabbi Nachman of Bratslav)
The evidence for identifying the
Murex trunculus as the source of
tekhelet is decisive, and goes beyond merely fitting the
general descriptions of the
Chilazon as found in the Talmud:
- The Jerusalem Talmud (as quoted by the Raavyah) translates
tekhelet as porphiron (the Latin and Greek name for
trunculus-like shells). Pliny and Aristotle describe these
shells as the source of the ancient dyes.
- The Talmud indicates that true tekhelet is indistinguishable
from the blue dye of vegetable origin -
kala ilan (indigo). The dye ultimately derived from
trunculus is molecularly equivalent to indigo.
- Extensive marine biological surveys have revealed that the
only snails in the Mediterranean which produce stable dyes are those of the
Murex family. The dye obtained from trunculus is very stable
and steadfast, which accords with the Rabbinical description of
- Archeologists in Tyre and elsewhere uncovered mounds of
Murex shells dating from the Biblical period which were
broken in the exact spot necessary to obtain the dyestuff.
Chemical analysis of blue stains on vats from 1200 BCE reveals patterns
consistent with those of modern day
- When listing the precious commodities used in building the
Mishkan (tabernacle), the Torah consistently includes
tekhelet along with gold, silver, and other familiar materials,
recognized by all for their worth. Yechezkel speaks of the
tekhelet from Tyre and the "Isles of Elisha", and the
Megillah tells us that in Persia, Mordechai wears royal clothes
made of tekhelet. Surely, the Torah is referring to that same
valuable dye commonly used by royalty throughout the rest of the ancient
Shard of a vat found at Tel Shikmona
from the Bronze Age, 3200 years old.
The chemical composition of the stain is
identical to the dye obtained from
"The revelation of the Chilazon is a sign that the redemption is
(Divrei Menachem 25)
Recently much has been accomplished to reestablish the
tekhelet dyeing process. Dr. Irving Ziderman, of the
Israel Fiber Institute, has published a number of articles
describing the scientific aspects and religious implications of the
trunculus dye. Rabbi Menachem Borstein has written a book
surveying the relevant Jewish legal aspects of
tekhelet, and Prof. Tzvi Koren, of the Shenkar College of Fibers,
has done rigorous chemical analysis of the dye from present day snails as
compared with samples from archeological artifacts dating back 3,200 years. Until a few years ago, however, tekhelet could be found only in the library or the laboratory.
In 1985, Rabbi Eliahu Tavger of Jerusalem began researching and writing a
book about ritual fringes - the tsitsit - and became convinced that
authentic tekhelet had been discovered. Determined to actualize his
newfound knowledge, and after much trial and error, he succeeded in
applying the process according to the
halakha from beginning to end. Based on Rabbi Tavger's
P'til Tekhelet was formed in an effort to provide
tekhelet to the general public. Today, after more than 1,300 years,
tsitsit are again being made with the elusive thread of
P'til Tekhelet - The Association for the Promotion and Distribution of Tekhelet -
is a non-profit organization based in Israel. P'til Tekhelet provides educational programming and resources pertaining to
Tekhelet, and produces Tekhelet for tsitsit. The association is comprised of a small group of individuals whose work is done
lishma - for the express purpose of making tsitsit as the halakha requires.