The elusive Biblical blue, a sacred color whose exact shade has puzzled scholars for centuries, has been revealed in a nearly 2,000-year-old patch of dyed fabric.
The piece of cloth was found in Israeli caves just south of Qumran, where the Dead Sea Scrolls were discovered between 1946 and 1956. It features a blue hue called 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.
But the biblical dye was lost in antiquity, and scholars have long attempted to rediscover its origins.
A team of researchers at the Israel Antiquities Authority (IAA) analyzed the dye of 180 textiles specimens from the Judean Desert caves.
Using advanced analytical instrumentation for identifying dye substances, the researchers found that most textiles were dyed using substances derived from plants.
However, three fabrics — two purple-colored textiles and the bluish cloth — were dyed using two of the most expensive materials in antiquity: excretions from a sea snail named Murex trunculus and crushed specimens of the insect American Cochineal.
"These Roman-era fabrics represent the most prestigious colors in antiquity: indigo, purple and crimson," the IAA said in a statement.
The researchers traced the woolen tekhelet textile to the Murex trunculus snail.
"The importance of this fabric is extremely significant as there are practically no parallels for it in the archaeological record," the IAA said.
Naama Sukenik, the IAA researcher who identified the rare dyed fabrics, added: “Until now, our most important discovery had been the piles and piles of Murex trunculus (hillazon snail) shells from the area, which served as a silent testimony to the presence of an ancient dyeing industry in Israel.”
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.
Scholars are still debating whether tekhelet was a sky-blue color or a rather a darker, purple-hued blue. Traditional interpretations indicate that tekhelet was a sky blue, symbolic of the heavens.
The newly identified fragment is sky blue.
Tests on the structure of the fabrics revealed the two purple fragments were most likely imported, while the tekhelet cloth was produced in the same fashion as the local fabrics.
“This sky blue fabric from the Dead Sea regions is definitive proof of both a colored fabrics trade and strict adherence to the biblical commandment of tekhelet in ancient Israel,” Sukenik said.
How the precious fabrics got into the caves remains a mystery.
According to te IAA researchers, they may have belonged to Jewish refugees from the time of the Bar Kochba Revolt (132-136 AD) against the Roman Empire.
Another theory is that the clothing may have belonged to a Roman military unit stationing by the caves after the Bar Kokhba revolt.
Image: The 2,000-year old textile contains the precious blue dye described in the Bible. Credit: Clara Amit, courtesy of the Israel Antiquities Authority.