Israeli researchers have identified three rare 2000-year-old fabrics that were dyed using one of the most expensive materials in antiquity -- a snail known as Murex trunculus.
These recovered parts of textile tunics were purple colored.
A third fabric was dyed with a mysterious blue dye known as tekhelet.
In accordance with the biblical commandment, tekhelet was used to dye the tassels, or tzitzit, attached to the four-cornered garment worn by Jews. It was also used as the color of ceremonial robes donned by high priests in the Jerusalem Temple.
Tekhelet was produced from the yellow glandular secretion of the Murex trunculus snail. Dipped into the solution for the dye, the fabrics turned blue after a brief exposure to air and sunlight.
Hundreds of snails were necessary to dye cloths, making tekhelet prohibitively expensive.