Asbestos

Stupid Question ™
Aug. 1, 2003
By John Ruch
© 2003

Q: Please settle our drunken bar bet: Is “asbestos” a trademark?
—Drunk and Drunker, Columbus, Ohio


A: Nope, though it’s often thought to be by old-timers who recall the word appearing in big, proud letters on fireproof theater curtains.

And that’s the big deal about asbestos: It’s utterly fireproof. So here’s the weird thing: “asbestos” is the Latin form of a Greek adjective meaning, as the “Oxford English Dictionary” says, “inextinguishable” or “unquenchable”—practically the exact opposite of fireproof.

How did that happen? Well, remember that the word was originally an adjective. Its first prominent use in Latin did not refer to the mineral we now call asbestos at all.

Dioscorides, the authority in Western pharmacology for centuries, used “asbestos” to describe quicklime. Quicklime, made by heating lime, can indeed seem unquenchable. If you toss water on it, you’re in for a rude surprise—it reacts violently and produces heat in excess of 200 degrees Fahrenheit.

Under the exaggerations of alchemy, “asbestos” entered English around 1300 as a term for a mythical stone that, once set alight, would never stop burning. It was claimed that one could make an eternally-burning candle from this “asbestos.”

Back in ancient times again, the great Roman naturalist Pliny was the first to use “asbestos” to mean the same substance we mean: a group of fibrous silicate minerals that can be woven like thread, are highly heat-resistant, and are impervious to water and most chemical reactions.

Pliny described towels woven of the stuff. Such cloth was a great party trick in palaces across Asia—dirty linens were cleaned by hurling them into a fire and pulling them out shiny.

But Pliny didn’t quite know what he was talking about. He thought the fibers were actually plant material, probably a fireproof form of flax. The Greeks called the material “amiantos,” meaning “undefiled” or “undefilable,” since you can burn all the impurities out of the mineral.

It’s unclear why Pliny called the stuff “unquenchable.” The “Oxford English Dictionary” suggests it was simply a mistake. But it may have been based on one of asbestos’ main ancient uses—as a wick for oil lamps.

The most famous such lamp was in the Erechtheum, a temple on Athens’ Acropolis. The lamp was refilled with oil only once a year, and burned continuously with a wick that never burned down. The traveler Pausanias around AD 150 explained that the wick was made of “Carpasian flax, the only kind of flax which is fireproof.”

Obviously, the “flax” was asbestos. The logic to the “asbestos” moniker is more clear: Asbestos is incombustible, but it allows oil within it to burn almost indefinitely without being “quenched” by the wick burning down, as happens in conventional cloth-wick lamps.

Asbestos-wick lamps are probably the basis for medieval legends about “perpetual lamps” found still burning in thousand-year-old pagan tombs.

It was only in the 1600s that the mineral and Pliny’s flax were identified as the same thing, and “asbestos” reentered English. It supplanted the former alchemy term—probably helped by the fact that both meanings relate to legends of eternally-burning lamps.