Nature has tucked a chemistry lab into a tiny sea snail: Hexaplex trunculus produces three molecules—indigo, monobromoindigo, and dibromoindigo. It’s this unique combination with brominated compounds that gives rise to a blue deeply significant in Jewish tradition. A heavenly blue. We call it Tekhelet.
Over 30 years ago, when Rabbi Eliyahu Tavger approached me to ask if I could support him in an important endeavor, I only knew the snail from diving. Nevertheless, we founded the Ptil Tekhelet Association in Jerusalem in 1991. Since then, we have been the only ones in the world producing the blue-and-white Tzitzit strings dyed with Tekhelet for the Jewish prayer shawl and passing on the knowledge about the color.
Every Jew knows the Torah passage that obligates us to attach these strings to our garments as a reminder of God’s commandments. But the ancient method of dyeing them had been lost to history. It wasn’t until the 19th century that Mediterranean sea snails of the genus Hexaplex (previously Murex) were identified as the source of the dyes.
The challenge: they yielded purple—not blue. The breakthrough came in the 1980s, thanks to Israeli chemist Otto Elsner. He discovered that exposing the dye solution to sunlight during the process triggered oxidation—transforming the color into blue.
In 1988, Rabbi Tavger succeeded in dyeing the strings as our ancestors once did. But the method was inefficient. So I took a break from the high-tech industry. With a PhD in physics and expertise in infrared spectroscopy and molecular behavior, I understood how light interacts with the snail’s molecules. I developed a more efficient dyeing technique—one that also met religious requirements. It worked: We’ve since sold over 300,000 strings to around 70 countries.
In ancient times, the purple and blue dyes from the snails were worth more than gold—reserved for the elite. Today, anyone can wear Tekhelet. It evokes the sky and the aspiration to reach beyond what is within our grasp. Even the blue in the Israeli flag is inspired by Tekhelet.
Being part of this story is a gift.
ELEMENTS-Newsletter
Get exciting insights into Evonik’s research and its societal relevance—delivered conveniently via email.