Hyacinthine purple

Years of Purple-Shell Dyeing Characterization of Hyacinthine Purple (Tekhelet)... 

Figure L Shells of marine snails used in purple dyeing. Left to right banded dye-murex (Trunculariopsis trunculus) for hyacinthine purple (tekhelet), spiny dye-murex (Bolinus brandaris) for Tyrian purple (arga-man), and the rock shell Thais haemastoma for Tyrian purple (argaman).

Scheme I. Major pathway for the transformation of natural colorless precursors obtained from banded dye-murex to hyacinthine purple (tekhelet ). J, 6,6 -dibromoindigotin 11 y potassium indoxyl sulfate 111, potassium 6-bromoindoxyl sulfate IV, indigotin E, enzymatic or acidic hydrolysis, and [0], aerobic oxidation. (Reproduced with permission from Ref. 7.

Some views do not distinguish between Tyrian and hyacinthine purples, whereas others contend that hyacinthine purple is the vegetable dye indigo. The sources of this confusion are discussed in the following paragraphs. 

Figure 4. Left, kela-ilan [archaic hyacinthine purple forgery (9, 20)] and right, contemporary hyacinthine purple from banded dye-murex. (Left photograph reproduced with permission from Ref. 20. Copyright 1968 Ciba-Geigy Review.)...

Spanier (14) has recently demonstrated a semiannual cycle in the availability of trunculus snails near Haifa. This cycle thus provides a biological basis for the proverbial seasonal rarity of the hyacinthine purple conchs. The snails bury themselves in the littoral sea bed in the... 

In regard to the technical feasibility of having obtained hyacinthine purple from Trunculariopsis trunculus in antiquity, Doumet (16) recently demonstrated that he could dye wool with the crushed shells, following the procedure of Tyre as described by Pliny the Elder, who visited Judea in person. Only techniques and materials available to ancient artisans were used in this experiment. 

The validity of the trunculus theory of the source of hyacinthine purple has now been corroborated by the identification of authentic archaeological remains of the dye on a textile from Palmyra some 1700 years old (8) and on a potsherd from the seventh century excavated near the Dead Sea. 

The major natural precursors of hyacinthine purple in the hypo-branchial gland are potassium indoxyl sulfate (Structure II in Scheme I) and its 6-bromo derivative (Structure III in Scheme I) (12). These are hydrolyzed and then aerobically oxidized to the final mixture of Structures I and IV (Scheme I). 

Tekhelet hyacinthine purple 6,6 -dibromoindigotin, indigotin Trunculariopsis trunculus... 

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