Three fabric dyes of animal origin were greatly prized in antiquity: kermes, tyrian purple, and hyacinthine purple. These colours are documented in mesopotamian texts from more than 3000 years ago and in the bible the first archaeological record is from crete (1600 bc).hyancinthine purple tekhelet unknown since the 7th century, has been difficult to distinguish from the redder tyrian purple. The author describes the historical and semantic problems involved and the 12 criteria for identifying the snail source as trunculariopsis trunculus. The colourant extrated is a mixture of indigotin (identical with vegetable indigo and 6, 6 dibromoindigotin (tyrian purple); together they form a unique violet colour. This identification of hyacinthine was corroborated by analysis of a palmyran textile and dead sea potsherd. Table, photographs, references. -- ICCROM