How a Snail Can Bridge Science and Religion

Hexaplex trunculus Linnaeus, 1758

Please allow me to clear something up right away: I loathe to mention science and religion in the same breath. But this story is sufficiently compelling to evoke such blaspheme. How can a humble snail bridge the gap?

An analytical chemist Zvi C. Koren specializing in ancient coloring agents, has identified a very special blue dye from the secretions of a common snail found in Israel, Murex trunculus, that scholars believe represents the original hue intended for “tekhelet,” used in Jewish prayer {reported in The New York Times today.}

How special is this blue? According to:

Maimonides, considered perhaps the greatest Jewish legal authority, said it resembled the color of the sky on a sunny day.

Even better:

“Tekhelet is the color of the sky,” Dr. Koren said in his laboratory. “It’s not the color of the sky as we know it; it’s the color of sky at midnight.” He paused and added, “It’s when you are all alone at night that you reach out to God, and that is what tekhelet reminds you of.”

This story entails several levels of intrigue that spans chemistry, physics and yes, religion.

If you dip wool into a “tekhelet” solution prepared using these snails, you can see something like this, when exposed to sunlight:


Such a solution could be used to prepare:

Source: The New York Times.
Though scientists and scholars are still debating the exact shade of the ritual blue, the dye used is modeled after a 2,000-year-old textile, above, and is produced from sea snails found in Israeli waters.

For those of you using tzitzit during prayer, this example may give pause that the special blue embedded within the tekhelet-colored threads is a reminder of not only the profundity of creation, but the connectedness of all creatures great and small, all molecules great and small for that matter. Should not the snail represent more than a coloring agent? Do you believe that this special hue represents something mystical or is it simply an ordinary dye from a common snail?


Dr. Koren is scheduled to deliver a paper on Monday at a conference here at Shenkar College of Engineering and Design, where he heads the Edelstein Center for Analysis of Ancient Artifacts.

I want to know what the chemical structure is! If someone finds it, please share!


  1. #1 TheBrummell
    February 28, 2011

    Tony Robinson (British actor) had a segment in his show “Worst Jobs in History” about dye making from snails. If it’s not the same dye it’s certainly very similar.

    Apparently, getting to that colour involved some pretty unpleasant labour. I didn’t look too closely, but there might be more on the chemistry somewhere else in the website I posted.

  2. #2 melior
    February 28, 2011

    At midnight, the sky is black, not blue, since it is very dark outside.

    Is indigo mystical too, or not so much because it comes from a non-holy continent?

  3. #3 Keith Harwood
    February 28, 2011

    Tony Robinson was making Tyrian purple, a dye so expensive that it was reserved for the Emperor of Rome and his imediate family. Presumably it is closely related to the blue dye described here.

  4. #4 Ian Kemmish
    March 1, 2011

    One needs look no further than Wikipedia to learn that both dies are indeed related, being obtained (first by the Phoenicians, apparently), from two species of the genus Murex.

    However, as I understand it, whether the religious dyestuff came from one of these two species, or from another, is, in the best traditions of the Abrahamic faith, not only unknown but unknowable.

  5. #5 altın çilek
    March 1, 2011

    Apparently, getting to that colour involved some pretty unpleasant labour. I didn’t look too closely, but there might be more on the chemistry somewhere else in the website I posted.

  6. #6 octopod
    March 1, 2011

    The NYT link seems to indicate that it’s chemically identical to indigo and woad.

  7. #7 LarianLeQuella
    March 1, 2011

    I wouldn’t say the snail bridges anything related to religion.

    What this snail is doing (or more precisely the scientists) is figuring something out using as many tools as they have at their disposal. No on is telling them how it was done based on some ancient text riddled with errors and contradictions. Whatever childish superstitions that spring up around this colour and its uses are totally irrelevant to the snail, and should be to a scientist.

    And yes, I am being rather pedantic, but having fun at it too.

  8. #8 Craig Heinke
    March 1, 2011

    Actually, the sky is blue at midnight, if the moon’s out (as the sky refracts the moon’s colors in the same way as the Sun’s). We can’t see it, but it shows up on long-duration astronomical photography.

  9. #9 becca
    March 2, 2011

    How does the snail feel about everything?

  10. #10 Jeff
    March 2, 2011

    Brilliant, Becca! Like many questions founded in religious faith, the answer is likely unknowable.

  11. #11 A. Ross
    March 3, 2011

    This blue is now all the rage in the Jewish orthodox community right now. When buying a tzizit you can request that the edges will be in this light blue. I am not religious but still find this to be a cool that this was the shade of blue during biblical times.

    This scientific discovery is similar to archaeologists discoveries of biblical times. Science helps us understand the past. While keeping God out of mix, lets not forget that history research heavily relays on science.

  12. #12 Jeff
    March 3, 2011

    Indeed. Thank you for your comment!

  13. #13 Drivebyposter
    March 3, 2011

    How a Star Bridges Science and Religion:

    Astronomers look at and study stars.
    The bible mentions stars.

  14. #14 John Birkbeck
    March 5, 2011

    I think the writer as so often oversteps with the religious references. The secretions of this and a related snail [Murex (Bolinus) brandaris] were used be the Pheonicians and others, including the Romans, to produce a purple dye called Tyrian purple or Royal purple. This faded to blue unless the dyeing conditions are right. The agent is 6, 6’dibromindigotin, an indigo derivative. In ancient times it was extremely expensive because of the number of snails needed to produce enought dye, hence it was used only by the aristocracy. Indigo itself is familiar as colouring blue jeans. For structure see

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