In the Bible, a shade of blue called tekhelet was God’s chosen color for the ancient Israelites. Tekhelet drapes adorned Solomon’s Temple, and tekhelet robes were worn by Israel’s high priests. According to Baruch and Judy Taubes Sterman in “The Great Tekhelet Debate—Blue or Purple?” in the September/October 2013 issue of BAR, even ordinary Israelites “were commanded to tie one string of tekhelet to the corner fringes (Hebrew, tzitzit) of their garments as a constant reminder of their special relationship with God” (Numbers 15:38–39). The tradition of blue tzitzit still exists today.
But what was the actual color of ancient tekhelet and blue tzitzit? Was it a shade of blue or was it closer to purple? Blue tzitzit and tekhelet-colored fabrics were widely worn and traded throughout the ancient Mediterranean, but by the Roman period, only the emperor could wear tekhelet. By the seventh century C.E., with the Islamic conquest of the Levant, the tekhelet’s source and method of manufacture were lost.
A century ago, Isaac Herzog, who would later become Israel’s first chief rabbi, researched tekhelet for his dissertation. He concluded that blue in the Bible was a bright sky-blue derived from the secretions of a sea snail, Murex trunculus.* This species was known to produce a murex dye the color of dark purple. Decades after Herzog’s death, chemist Otto Elsner proved that murex dye could in fact produce a sky-blue color by exposing the snail secretions to ultraviolet rays during the dyeing process. Sky-blue tzitzit, then, could be made with murex dye.
In the BAS DVD God’s Images in the Prophetic Books, Professor Julia M. O’Brien presents several engaging lectures about the many images of God found explicitly and implicitly in the prophetic books of the Old Testament, exploring them in their ancient Near Eastern context. Learn More >>
Despite Elsner’s discovery, the debate around the color of tekhelet continued. Dissenters argued that the ancient dyers, who created dyes in covered vats, likely didn’t know how to adjust the dye colors using the sun’s ultraviolet rays. Eleventh-century Biblical exegete Rashi described tekhelet as a deep blue or dark violet. A violet swatch of wool discovered during excavations at the first-century Herodian fortress of Masada was proven to have been colored by murex dye.
However, important evidence persuasively suggest that Biblical tekhelet was in fact sky-blue. Assyriologist Wayne Horowitz explains that the Sumerian word uqnu, the word for the gem lapis lazuli, was used for the color blue and its shades. The term was applied to the sky and to blue wool (uqnatu). When the foreign word takiltu, Hebrew tekhelet, was adopted into Akkadian, the same cuneiform signs as uqnatu were used. To the ancient Mesopotamians, therefore, the color of lapis lazuli and the sky were equivalent to the color of tekhelet.
So what was the color of Biblical tekhelet? The Jerusalem-based Ptil Tekhelet Foundation believes it was sky-blue derived from the murex dye. For over 25 years, this foundation has produced hundreds of thousands of blue tzitzit strings colored with murex dye. The blue tzitzit on Jewish prayer shawls remind worshipers of the sea, the sky and God’s holy throne.
BAS Library Members: Read the full article on ancient tekhelet by Baruch and Judy Taubes Sterman in Archaeological Views, “The Great Tekhelet Debate—Blue or Purple?” as it appears in the September/October 2013 issue of Biblical Archaeology Review.
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In a letter to BAR, Professor Zvi C. Koren, director of the Edelstein Center for the Analysis of Ancient Artifacts at the Shenker College of Engineering and Design in Ramat Gan, Israel, criticizes the Stermans’ analysis, to which the Stermans have replied. Visit the BAS Scholar’s Study: The Great Tekhelet Debate page today.