Scientific Research


Four exciting breakthroughs in our understanding of tekhelet have been reported recently:

  1. The main dyestuff of tekhelet dye has now been discovered. The main and characteristic ingredient of tekhelet is a hitherto unknown dyestuff named 6-monobromo-indigotin (MBI), in admixture with the two previously-known ingredients, 6,6′-dibromo-indigotin (DBI) and indigotin. Currently, we have been investigating the unique chemistry of MBI, which – when heated to 60 degrees C – changes irreversibly from its initial violet colour to blue, without any alteration in its chemical structure and composition. The DBI ingredient is also the dyestuff of Tyrian purple (Hebrew argaman,ארגמן), that is the dye produced from all other species of dye-shellfish, except banded dye-murex used for making tekhelet. The indigotin ingredient is a blue, that is also the vegetable dyes woad and indigo (קלא אילן).
  2. The millennium-old mystery of how tekhelet was dyed has now been unraveled by Edmonds and Boesken-Kanold . It is a unique bacterial fermentation taking a week, that converts the dye to a soluble form, which readily dyes wool to tekhelet. This natural process is spontaneous; and it has been restored to work in practice.
  3. Variations in the dye colour obtained with different specimens of banded dye-murex are now attributed to the size (i.e. the age) of the snail. The younger individuals largely give blues, while the older ones mostly give purples. Accordingly, use smaller shellfish to get a tekhelet colour!
  4. Excavations of High Priestly residences in Temple-era Old-City Jerusalem , have uncovered intact shells of banded dye-murex . This finding indicates that the shells were treasured as prestigious objects. Perhaps these shells were prized as revered symbols of the sacred goods made from them.

But not only for tekhelet! Also the opercula ציפורן of this shellfish were evidently used to make the onycha שחלת ingredient of the Holy Incense קטורת (Exod. 30: 34).

Scientific Correspondence

Foundation Principles in Restoring Dying Process of Antiquity

Date: June 4 Correspondence between MF and IZ MF: Dear Dr. Ziderman, I am excited to have found your site and foundation. First of thank you for being at the forefront of this important Mitzvah for Klal Yisroel. I very much agree with your foundation principals.  As a wearer of murex Tekhelet for many years now it […]

Questions on Tekhelet Decomposition Process

Date: May 21, 2020 Email correspondence between Dr. Israel Ziderman and Rafi Hecht. You mentioned before that Ptil and co. strip the monobromoindigotin dyestuff into indigotin, which you feel makes it kala ilan. Questions: 1. Does that mean that in Menachot 42b, Shmuel bar R’ Yehuda was wrong in adding Sammemim? If not, what would […]

Is the Snail the Chilazon of the Talmud

Date: May 17, 2020 AP: Does Chilazon – the snail fit the description in the Talmud? IZ: 1. Following the late Chief Rabbi Herzog, I have demonstrated that the 4 criteria in the talmud are fulfilled in the banded-dye murex (H.trunculus). Do you have any difficulty with my publications on this? 2. Besides that let […]

Mixing Cuttlefish with Murex

Date: May 19 MDR: Why not mix the Radzyner Rebbe’s cuttlefish and the murex to create a dye that satisfies both views? The Radzyner process already mixes it with other things, so why not mix the two together to avoid machloces? These discussions here have dealt largely with hypothetical claims and opinions. However the reality […]

Why the Murex Trunculus Snail Alone Can Be Used for Tekhelet

Date: April 20, 2020 Israel Ziderman (IZ): Our source in the Tosefta is quite unambiguous: הביא מן החלזון כשרה שלא מן החלזון פסולה. The definite article ה requires a particular species of snail, and would not include any other snail species. The apparently superfluous law שלא מן החלזון פסולה is unequivocal in rejecting any other […]

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