THE RAREST BLUE

With his wife, dye expert Sterman delivers a history of a blue dye mentioned in ancient texts but only recently recreated in the modern era.

The Stermans trace the history of tekhelet, a blue dye derived from the glands of certain types of snails that they describe as the “sacred, rarest blue.” The Talmud and other texts of Judaism mention tekhelet; the Book of Numbers in the Bible, for example, requires Jewish people to tie a tekhelet-dyed thread to the corners of their clothing. Tradition specifically dictated that the tekhelet had to be “sky blue,” write the authors, and the use of other blue dyes, such as indigo, was prohibited. But tekhelet was expensive, difficult to make and even illegal during the era of the Roman Empire. As a result, the tradition waned, and many details of the tekhelet-making process were lost for hundreds of years. The Stermans delve into Jewish history, showing how doctrinal skirmishes erupted over the use of the dye and how figures such as the first chief rabbi of Israel and other researchers explored tekhelet’s mysteries. The authors also recount their efforts to mass-produce authentic tekhelet-dyed strings, with the authors traveling to far-off places to collect the snails required. While their dedication is admirable and their research comprehensive, the prose simply isn’t engaging enough to bring an entire book about an obscure blue dye to life. The latter sections, especially, which include technical descriptions of snails’ physical processes and multiple molecular diagrams, may be tough going for casual readers. That said, the book may hold some appeal for aficionados of either religious history or the study of mollusks—surely one of the few books for which that may be said.

An ambitious but overlong history.