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A set of Tzitzit, four tassels or "fringes" with blue threads produced from a Hexaplex trunculus based dye — tied according to the opinion of the Sefer ha-Chinuch.

Tekhelet (Hebrew: תְּכֵלֶת; alternate spellings include tekheleth, t'chelet, techelet and techeiles) is a "blue-violet",[1] "blue",[2] or "turquoise"[3] dye highly prized by ancient Mediterranean civilizations and mentioned 49[4][5] times in the Hebrew Bible/Tanakh. It was used in the clothing of the High Priest, the tapestries in the Tabernacle, and the tzitzit (fringes) affixed to the corners of one's four-cornered garments, including the tallit.[4]

Tekhelet dye was critical for the production of certain articles in the Jerusalem Temple, as well as for the commandment of tzitzit. Tekhelet is most notably mentioned in the third paragraph of the Shema, quoting Numbers 15:37–41. However, neither the source nor method of production of Tekhelet is specified in the Bible, but according to the Tosefta[6] the Ḥillazon is the exclusive source of the dye. The Talmud further informs us that the dye of Tekhelet was produced from a marine creature known as the Ḥillazon.[7]

A garment with tzitzit has four tassels, each containing four strings. There are three opinions in rabbinic literature as to how many of the four strings should be dyed with tekhelet: two strings;[8] one string;[9] or one-half string.[10] Knowledge of how to produce tekhelet was lost in medieval times, and since then tzitzit did not include tekhelet. However, in modern times, many Jews believe they have identified the Ḥillazon and rediscovered tekhelet manufacture process, and now wear tzitzit which include the resulting blue dye.

Biblical references[edit]

Of the 49[11] or 48 [4][5] uses in the Masoretic Text, one refers to fringes on cornered garments of the whole nation of Israel (Numbers 15:37–41), 44[citation needed] refer to the priesthood or temple clothes and garments. The remaining 6[citation needed] in Esther, Jeremiah and Ezekiel are secular uses; such as when Mordechai puts on "blue and white" "royal clothing" in Esther. The color could be used in combination with other colors such as 2 Chronicles 3:14 where the veil of Solomon's Temple is made of blue-violet (Tekhelet), purple (Hebrew: אַרְגָּמָן Argaman) and scarlet (Biblical Hebrew: שָׁנִי (Shani); Late Biblical, Modern Hebrew: כַּרְמִיל karmiyl). Ezekiel 27:7 may indicate the source of the shellfish to have been the Aegean region.[12] In addition to the above observations it should be added that all of the instances of tekhelet (both secular and priestly) attribute its usage to some kind of elite. From this perspective it becomes obvious that it was difficult to obtain and expensive what is further corroborated by the later rabbinic writings.[13]


Murex shells from the Iron Age II period (10th-7th centuries BCE) with ancient remains of purple on the shards seen on the rights.

At some point following the Roman destruction of the Second Temple, the actual identity of the source of the dye was lost, and during a period of over 1,400 years, most Jews have only worn plain white tassels (Tzitzit).[14]

How was tekhelet lost if the Jews are supposed to wear it every day? There is a theory that it was lost due to the restrictions put on using the blue dye during the roman empire (this theory only applies if the Murex trunculus is the correct Ḥillazon). Caesar and Augustus restricted the use of the Murex dye to the governing class.[15] Nero made laws that stated no one was allowed to wear blue because it was the color of royalty, and specifically he forbid goods from the Purpura, the name used for the Murex trunculus in ancient times, and that anyone who wears it will be put to death.[16][17][18] This idea that it was illegal to wear tekhelet is corroborated by the Talmud in the Tractate Sanhedrin where Rabbis were caught by troops while trying to smuggle in tekhelet. The Ramban also describes how tekhelet was worn by the royalty and outlawed for other people. The reason why the royalty used the Murex dye as opposed to indigo which looked the same was because indigo faded. However once they figured out how to make indigo endure they stopped using the Murex trunculus because indigo was much cheaper. At that time is when people stopped using the Murex trunculus for its Dye entirely.[19]

The stripes on prayer shawls, often black, but also blue or purple, are believed by many to symbolize the lost Tekhelet which is referred to by various sources as being "black as midnight", "blue as the midday sky", and even purple.[20] These stripes of tekhelet inspired the design of the flag of Israel.

Identifying the color of tekhelet[edit]

Despite the general agreement of the most of the modern English translations of the phrase, the term tekhelet itself presents several basic problems. First of all, it remains unclear to what extent the word in biblical times denoted an abstract color or the actual source material. This problem is specific neither to the tekhelet nor to the biblical Hebrew and the scholars often point to other languages which feature similar phenomena.[21] Second, although with time it came to denote the color blue solely, the exact hue in the Antiquity remains unknown. Basing on the scarce material evidence from the ancient Near East and the early biblical translations the scholars suppose that tekhelet probably belonged to the spectrum between blue, red and purple.[22]

In the Septuagint, tekhelet was translated into Greek as hyakinthos (ὑακίνθος, "hyacinth"). The color of the hyacinth flower ranges from violet blue to a bluish purple.

The early rabbinic literature in turn provide two main expositions for the color of techelet. One group of sources, including Bava Metziya 61a-b and Menachot 40a-b, mentions qala ilan, an indigo dye described as visually indistinguishable from tekhelet. Yet, although this dye was much cheaper to obtain, the rabbis cursed those who substituted techelet with some low-priced equivalent and in fact preferred to annul the obligation altogether rather than to compromise its value (Mishnah Menachot 4:1), which clearly proves that it was not the color which mattered most. The second and much more numerous group compares the tekhelet to the color of the sky or the sea which is not far off from indigo. More importantly, however, this group contains several instances (Menachot 43b, Sotah 17a, Hullin 89a, Numbers Rabbah 4:13, 17:5) which extend the comparison and liken the tekhelet to the throne of glory. Apparently, the particular features of this divine chair are not speculated in the Early Rabbinic Literature, but it can be safely assumed that, again, these were not the visual qualities which counted here but rather the extraordinary value of the object and its explicit cultic associations.[13]

Rashi describes the color of tekhelet as “poireau,” the French word for leek, transliterated into Hebrew.

In conclusion, its color varies between central sky blue in sunlight, through the iris indigo of the rainbow to deep African violet in dull weather; translated in a German translation of the biblical book of Exodus, as "blauem purpur".[citation needed]

Identifying the ḥillazon[edit]

Various sea creatures have been suggested as the ḥillazon, the purported source of the blue dye.[23][24][25][26]

Hexaplex trunculus[edit]

A guide from the Ptil Tekhelet Foundation shows how a piece of wool, dipped into the solution for the Hexaplex trunculus based dye, turns into leek-like green in sunlight, and eventually into (dark) blue with a purple hue.

In his doctoral thesis (London, 1913) on the subject, Rabbi Yitzhak HaLevi Herzog (1889–1959) named Hexaplex trunculus (then known by the name "Murex trunculus") as the most likely candidate for the dye's source. Though Hexaplex trunculus fulfilled many of the Talmudic criteria, Rabbi Herzog's inability to consistently obtain blue dye (sometimes the dye was purple) from the snail precluded him from declaring it to be the dye source.

According to Zvi Koren, a professor of chemistry, Tekhelet was close in color to midnight blue.[27] This conclusion was reached based on the chemical analysis of a 2000-year old patch of dyed fabric recovered from Masada in the 1960s.[28] The sample, shown to have been dyed with Murex snail extraction, is a midnight blue with a purplish hue. Additionally, in 2013, Na'ama Sukenik of the Israel Antiquities Authority verified a 1st-century CE-dated fragment of blue-dyed fabric to have used H. trunculus as the source of its pure blue color.[29]

In the 1980s, Otto Elsner,[30] a chemist from the Shenkar College of Fibers in Israel, discovered that if a solution of the dye was exposed to ultraviolet rays, such as from sunlight, blue instead of purple was consistently produced.[31] In 1988, Rabbi Eliyahu Tavger dyed Tekhelet from H. trunculus for the Mitzvah (commandment) of Tzitzit for the first time in recent history.[32] Based on this work, four years later, the Ptil Tekhelet Organization was founded to educate about the dye production process, and to make the dye available for all who desire to use it. The television show The Naked Archaeologist interviews an Israeli scientist who also makes the claim that this mollusk is the correct animal. A demonstration of the production of the blue dye using sunlight to produce the blue color is shown. The dye is extracted from the hypobranchial gland of Hexaplex trunculus snails.[25]

Chemically, exposure to sunlight turns the red 6,6'-dibromoindigo in snails into a mixture of blue indigo dye and blue-purple 6-bromoindigo. The leuco (white) solution form of dibromoindigo loses some bromines in the ultraviolet radiation.[33]

Proofs for the Hexaplex (Murex) Trunculus[edit]

The Talmud in the tractate Chulin says that tekhelet is the color of the sea and the sky. So it seems that the color is blue. The Talmud in Bava Metzia says that only God can distinguish between Kala Ilan(indigo) and techieles. Which means that tekhelet is similar to indigo in color. The dye produced by the Murex trunculus has the exact same chemical composition as Kala Ilan.[18] There is a further discussion that since they have the same chemical structure it is a proof that tekhelet is not the Hexaplex trunculus because the Talmud gave tests to distinguish between indigo and tekhelet but if they have the same chemical structure then the tests would not work.[34][35]

In the Talmud, in the tractate Shabbat it says that the Ḥillazon is found from Tzor until Haifa. There is archeological evidence of an ancient dye creating industry in Tel Shikmona, south of Haifa. There were large amounts of purple coloring preserved in vats that were confirmed to have been produced from sea snails. There were also manufacturing equipment for textiles found in the area. Some people argue this was a site for producing tekhelet in ancient times.[36] Hundreds of yards of murex shells have also been found in the area from Tzor until Haifa.[37]

In Parashat Eikev it says that the Jews clothing did not wear out from on them and there is a midrash, an ancient commentary on Torah, that compares the Jews clothing in the desert to the shell of the Ḥillazon because their clothing did not wear out.[38] Implying the Ḥillazon has a shell that does not wear out just as the Murex trunculus has a shell that grows with it making it a good comparison to the clothing. Also the Talmud in the Tractate shabbos describes extracting the dye from the Ḥillazon by cracking it open which could also lead to the conclusion that it has a shell.[39]

The word porforin, or porpora, or porphoros is used in midrash as well as many other Jewish texts to refer to the Ḥillazon that we get tekhelet from and this is the Latin or Greek[40] translation of Murex trunculus. Pliny and Aristotle also both refer to the Porpura as being the source for purple and blue dyes, showing that the Murex has a long history of being used for blue dye.[19]

Rav Herzog wrote a doctoral thesis on tekhelet in 1914 and was convinced the tekhelet was from the Murex trunculus as he wrote “it is very unlikely that the tekhelet-hillazon is not the snail called murex trunculus, but though unlikely, it is still possible.”[41][42] However, in his lifetime he could not figure out how to get the dye to be blue, it always came out purple.

The word Ḥillazon also means snail in Arabic.[43]

Another requirement according to the talmud is that the dye cannot fade and the Murex dye does not fade and can only be removed from wool with bleach.[44]

In the Tractate Megillah it quotes a pasuk in Deuteronomy 33:19 saying that treasures are hidden in the sand and compares treasure to a Ḥillazon which is hidden in the sand by its shell.[45] However, the Talmud goes on to explain that literally only the word treasure is referring to the Ḥillazon and therefore hidden in the sand does not have to relate to the Ḥillazon literally being found in the sand.

Proofs against the Hexaplex (Murex) Trunculus being the Ḥillazon[edit]

In the tractate Menachot it states that the Ḥillazon's body is similar to the sea.[46] Some people argue that the body of it should be blue based on this, however the body of the Murex trunculus is not blue. The possible responses interpret the implications of its body being similar to the sea differently.

There are two other snails that produce the exact same dye as the Murex trunculus, the murex brandaris and purpura (thais) Haemastoma, so how do we know which one is the Ḥillazon. There is a theory that the Murex trunculus contains more natural indigo and that is why it is used. Some argue that they would all be kosher, valid to use, and considered the Ḥillazon.[47]

The Rambam, Tosafot, and Rashi in one place says the Ḥillazon is a fish and the Murex trunculus is a snail not a fish. One answer given is that maybe anything in the sea is called a fish.[35]

A midrash in Numbers says that tekhelet was hidden and now we only have white strings.[48] Some people explain that hidden means hidden for good, or hidden until the messiah comes so it cannot be that we found the tekhelet. In the Medrish Sifrei it says that tekhelet is hidden until the next world.[49]

In the Tractate Menachot it says that the Ḥillazon comes up once in 70 years.[46] It is unclear what this is exactly referring to but the Murex trunculus has no known cycle that would give rise to a statement based on cycles.[50]

It says in the Tractate Shabbat that if you trap the Ḥillazon on shabbat you are over the violation of trapping on shabbat however certain commentaries hold that you are not over the violation of trapping if you trap a snail because it is so easy to trap them. Therefore, the Ḥillazon cannot be a snail[35] Others argue that since you have to take a boat into the water and it is a burden to trap the snails you would still be over trapping on shabbat.[51]

Sepia officinalis[edit]

In 1887, Grand Rabbi Gershon Henoch Leiner, the Radziner Rebbe, researched the subject and concluded that Sepia officinalis (common cuttlefish) met many of the criteria. Within a year, Radziner chassidim began wearing Tzitzit that included threads dyed with a colorant produced from this cephalopod. Rabbi Herzog obtained a sample of this dye and had it chemically analyzed. The chemists concluded that it was a well-known synthetic dye "Prussian blue" made by reacting Iron(II) sulfate with an organic material. In this case, the cuttlefish only supplied the organic material which could have as easily been supplied from a vast array of organic sources (e. g., ox blood). R. Herzog thus rejected the cuttlefish as the Ḥillazon and some[who?] suggest that had the Grand Rabbi Gershon Henoch Leiner known this fact, he too would have rejected it based on his explicit criterion that the blue color must come from the animal and that all other additives are permitted solely to aid the color in adhering to the wool.[52]


Within his doctoral research on the subject of Tekhelet, Herzog placed great hopes on demonstrating that Hexaplex trunculus was the genuine snail Ḥillazon. However, having failed to consistently achieve blue dye from Hexaplex trunculus, he wrote: “If for the present all hope is to be abandoned of rediscovering the Ḥillazon Shel Tekhelet in some species of the genera Murex (now "Hexaplex") and Purpura we could do worse than suggest Janthina as a not improbable identification".[53] Blue dye has in the meantime been obtained from Hexaplex trunculus snail and the pigment molecule itself is hypothesized to be Tyrian Purple or Aplysioviolin.[54] In 2002 Dr. S. W. Kaplan of Rehovot, Israel, sought to investigate Herzog's suggestion that Tekhelet came from the extract of Janthina. After fifteen years of research he concluded that Janthina was not the ancient source of the blue dye.

Traditional Jewish Law Discussions Surrounding Tekhelet[edit]

There is a concept when studying Jewish law that when we are in doubt about the laws of a commandment from the Torah, we act stringently so some Rabbi's apply that to our case and say since we are in doubt whether we have the correct dye, we should wear it anyway. Others argue and say that concept only applies in cases such that after one acts stringently they 100% fulfill the commandment and that would not be true here since it would still be a doubt if we wore true tekhelet.[34]

There is another rule in Judaism based on a verse in Deuteronomy 14:1 that the Talmud explains that we should not make fractions among the Jewish people. Therefore, if a person acts differently from the rest of the Jewish people they are creating fractions.[55] Since most Jews do not wear tekhelet it can be considered violating the principle of not making fractions in the Jewish People if one were to wear tekhelet.

The Rambam says the Ḥillazon secretes something black and the murex trunculus does not.[35]

In the Tractate Menachot[56] and the Rambam explain the process for making the dye for tekhelet and neither of them mention explicitly that it needs to be placed in the sunlight. Putting the dye in sunlight is a requirement to make the dye from the murex trunculus.[35]

There is another commandment not to detract from any law. Rav Schachter says that if we know what tekhelet is and we are wearing the tzizit strings without the blue string[s] then we are detracting from the law and are violating a commandment.[19] Many other Rabbi's do not agree with this statement.

Different Opinions On Tying Tekhelet[edit]

The Rambam holds that half of one string should be colored blue and it should wrap around the other seven white strings. It should wrap around three times and then leave some space and then three more and leave some more space and should continue like this for either 7 or 13 groups. The first and last wrap around should be from a white string not a blue string.[57]

The Raavad holds that one full string should be blue and there should be four groups of at least seven coils alternating between white and blue both beginning and ending with blue.[57] There are multiple other opinions of how to tie the tzizit if one full string is blue.

Tosafot holds that two full strings should be tekhelet. He holds the coils should be groups of three starting with three white then three blue alternating and ending with three white.[58] There is another way to tie using two full string that Rav Schachter follows based on the opinion of Rav Shmuel Ben Hofni Gaon.[57]


See also[edit]


  • Gadi Sagiv, 'Deep Blue: Notes on the Jewish Snail Fight'
  • Hoffmann, Roald; Leibowitz, Shira (1997). Old wine, new flasks : reflections on science and Jewish tradition. New York: W. H. Freeman. ISBN 978-0716728993.
  • Sterman, Baruch; Taubes, Judy (2012). The rarest blue : the remarkable story of an ancient color lost to history and rediscovered. Guilford, Conn.: Globe Pequot Press. ISBN 978-0762782222.
  • KolRom Media, 'Techeiles - It's Not All Black and White'


  1. ^ Everett Fox, The Five Books of Moses: A New Translation with Introductions, Commentary, and Notes. New York: Schocken Books, 1995.
  2. ^ "Techelet (Blue Thread)". Tzitzit and Tallis. Chabad Media Center. Retrieved 9 April 2013.
  3. ^ Chaim Miller, ed. (2006). Chumash : the five books of Moses : with Rashi's commentary Targum Onkelos and Haftaros with a commentary anthologized from classic rabbinic texts and the works of the Lubavitcher Rebge (Synagogue ed.). New York, N.Y.: Kol Menachem. p. 967. ISBN 9781934152010.
  4. ^ a b c Zohar, Gil. "Fringe Benefits – Kfar Adumim factory revives the lost commandment of tekhelet". www.ou.org. Retrieved 14 March 2013.
  5. ^ a b Amir, Nina. "Lost thread of blue, tekhelet color reestablished". Religion & Spirituality. Clarity Digital Group LLC d/b/a Examiner.com. {{cite web}}: Missing or empty |url= (help)
  6. ^ Tosefta Menachot9:6
  7. ^ Menachot 44a
  8. ^ Rashi, Tosafos, Rosh
  9. ^ Raavad
  10. ^ Rambam
  11. ^ "Strong's Hebrew: 8504. תְּכֵ֫לֶת (tekeleth) -- violet, violet thread". biblesuite.com.
  12. ^ Gesenius Hebrew lexicon entry for "Isles of Elisha" – more modern source needed
  13. ^ a b Kosior, Wojciech (2018-07-27). ""Like a Throne of Glory:" The Apotropaic Potential of Ṣîṣîṯ in the Hebrew Bible and Early Rabbinic Literature". Review of Rabbinic Judaism. 21 (2): 176–201. doi:10.1163/15700704-12341342. ISSN 1570-0704. S2CID 171703270.
  14. ^ Rabbi Mois Navon. "On History, Mesorah and Nignaz" (PDF). Threads of Reason: A Collection of Essays on Tekhelet.
  15. ^ 4 Seutonius, Vita Caes, p. 43, Dio Cassius, bk XLIX, p.161
  16. ^ Sterman, Baruch. "Tekhelet" (PDF).
  17. ^ Suetonius The Twelve Caesars Book Six: XXXII
  18. ^ a b Herzog, Isaac (1987). The Royal Purple and the Biblical Blue. Keter Publishing House. p. 73.
  19. ^ a b c "YUTorah Online - The Techeiles Revolution: Archeology, Chemistry, Mesorah, Debate and More (Rabbi Hershel Schachter, Rabbi Aryeh Lebowitz, Rabbi Dr. David Shabtai, Rabbi Efrem Goldberg)". www.yutorah.org. Retrieved 2021-10-20.
  20. ^ Simmons, Rabbi Shraga. Tallit stripes
  21. ^ Tomasz Sikora, “Color Symbolism in the Jewish Mysticism. Prolegomena” (Polish), Studia Judaica 12.2 (2003): 47.
  22. ^ Robert Laird Harris, Gleason L. Archer and Bruce K. Waltke, Theological Wordbook of the Old Testament, (Chicago, 1980/2013) [TWOT] (CD-ROM), 2510.0.
  23. ^ The International Standard Bible Encyclopedia – Page 1057 Geoffrey W. Bromiley – 2007 "The most highly prized dye in the ancient world obtained from the secretions of four molluscs native to the eastern Mediterranean: helix ianthina, murex brandaris, murex trunculus, and purpura lapillus. Various shades could be produced"
  24. ^ Hoffmann, Roald; Leibowitz, Shira (1997). Old wine, new flasks : reflections on science and Jewish tradition. New York: W. H. Freeman. ISBN 978-0716728993.
  25. ^ a b Hoffmann, Roald (April 19, 2012). "Indigo - A Story of Craft, Religion, History, Science and Culture". Special Collections & Archives Research Center Oregon State University Libraries. Retrieved 16 February 2015.
  26. ^ Sterman, Baruch; Taubes, Judy (2012). The rarest blue: the remarkable story of an ancient color lost to history and rediscovered. Guilford, Conn.: Globe Pequot Press. ISBN 978-0762782222.
  27. ^ "The color 'techelet'". jpost.com.
  28. ^ Kraft, Dina (2011-02-27). "Rediscovered, Ancient Color is Reclaiming Israeli Interest". New York Times.
  29. ^ "Why so blue? Biblical dye was made from snails". NBC News. Associated Press. Dec 31, 2013. Retrieved December 31, 2013.
  30. ^ Robin Ngo (11 September 2013). "What Color Was Tekhelet?". Retrieved 20 January 2014. Decades after Herzog’s death, chemist Otto Elsner proved that murex dye could in fact produce a sky-blue color by exposing the snail secretions to ultraviolet rays during the dyeing process. Sky-blue Tzitzit, then, could be made with murex dye.
  31. ^ O. Elsner, "Solution of the enigmas of dyeing with Tyrian purple and the Biblical tekhelet", Dyes in history and Archaeology 10 (1992) p 14f.
  32. ^ Navon, Mois (December 30, 2013). "Threads of Reason-A Collection of Essays on Tekhelet" (PDF). p. 23. Retrieved 20 January 2014. In 1985, while writing a book about Tzitzit entitled Kelil Tekhelet, R. Eliyahu Tavger became convinced that the source of authentic Tekhelet had been found. Determined to actualize his newfound knowledge, and after much trial and error, he succeeded in applying the process, according to Halakhah, from beginning to end. He thus became the first person, since the loss of the Ḥillazon, to dye Tekhelet for the purpose of Tzitzit. In 1991, together with R. Tavger, Ptil Tekhelet was formed to produce and distribute Tekhelet strings for Tzitzit.
  33. ^ Ramig, Keith; Lavinda, Olga; Szalda, David J.; Mironova, Irina; Karimi, Sasan; Pozzi, Federica; Shah, Nilam; Samson, Jacopo; Ajiki, Hiroko; Massa, Lou; Mantzouris, Dimitrios; Karapanagiotis, Ioannis; Cooksey, Christopher (June 2015). "The nature of thermochromic effects in dyeings with indigo, 6-bromoindigo, and 6,6′-dibromoindigo, components of Tyrian purple". Dyes and Pigments. 117: 37–48. doi:10.1016/j.dyepig.2015.01.025. A more blue shade can be obtained if the reduced form of DBI, leuco-DBI, is exposed to sunlight whereupon it is debrominated. Then on oxidation, MBI and indigo are formed.
  34. ^ a b Epstein, Menachem. "Has Tekhelet been found?". Hakirah: 175–176.
  35. ^ a b c d e "Techeles Hachodosh - Rabbi Reisman". Techeiles Chabura. Retrieved 2021-10-20.
  36. ^ "Biblical era purple dye industry discovered in Haifa". The Jerusalem Post | JPost.com. Retrieved 2021-10-20.
  37. ^ Epstein, Menachem. "Has Tekhelet been found?". Hakirah: 167.
  38. ^ Deuteronomy 8:4
  39. ^ Shaboss 75a
  40. ^ "About Us". Techeiles Chabura. Retrieved 2021-10-20.
  41. ^ Herzog, Isaac (1987). The Royal Purple and the Biblical Blue.
  42. ^ https://tekhelet.com/pdf/HerzogDoctorate.pdf
  43. ^ "Snail – an Arabic word". arabic.fi. Retrieved 2021-10-20.
  44. ^ Hellmann, Meir. Levush Haaron. p. 20.
  45. ^ Megila 6a
  46. ^ a b Menachot 44a
  47. ^ "Ask Ptil Tekhelet". Ptil Tekhelet. Retrieved 2021-10-20.
  48. ^ Bamidbar Rabbah 17:5
  49. ^ Sifrei Deuteronomy 354
  50. ^ Singer, Ph.D, Mendel E. "Understanding the Criteria for the Chilazon". www.tekhelet.com. Retrieved 2021-10-20.{{cite web}}: CS1 maint: url-status (link)
  51. ^ Rabbi Lebowitz response to Rav Reisman
  52. ^ P'til T'khelet, p.168
  53. ^ Herzog, p.71
  54. ^ Kitrossky, Levi. "Do We Know Tekhelet?" (PDF).
  55. ^ Yevamot 13b
  56. ^ Menachot 42b
  57. ^ a b c Schachter, Rabbi Hershel. "Using Tekhelet in Tzizit" (PDF): 51–62. {{cite journal}}: Cite journal requires |journal= (help)
  58. ^ Menachot 39a

External links[edit]