Techelet

Tekhelet (Hebrew: תכלת‬ təḵêleṯ, "blue-violet", or "blue", or "turquoise" (alternate spellings include tekheleth, t'chelet, techelet and techeiles) is a blue dye mentioned 49 times in the Hebrew Bible/Tanakh. It was used in the clothing of the High Priest, the tapestries in the Tabernacle, and the tassels (Hebrew: ציצית, Tzitzit (or Ṣiṣiyot) [tsiˈtsit], pl. Tzitziyot or Ṣiṣiyot) affixed to the corners of one's four-cornered garment, such as the Tallit (garment worn during prayer, usually).

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.

According to the Talmud, the dye of Tekhelet was produced from a marine creature known as the Ḥillazon (also spelled Chilazon). According to the Tosefta (Men. 9:6), the Ḥillazon is the exclusive source of the dye.

After the destruction of the Temple in Jerusalem by the Romans, the sole use of the Tekhelet dye was in Tzitzit. A set of Tzitzit consists of four tassels, some of their strands being Tekhelet, which Rashi describes as green as “poireau,” the French word for leek, transliterated into Hebrew. There are three opinions in Rabbinic literature as to how many are to be blue: 2 strings; 1 string; 1 half string. These strands are then threaded and hang down, appearing to be eight. The four strands are passed through a hole 25 to 50 mm away from the corners of the four-cornered cloth.

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