What is asbestos?

asbestos fibres

The name "asbestos" comes from a Greek word that means "will not burn." There is nothing surprising about a mineral that will not burn. Not many minerals will. But asbestos is different from most minerals in this way: it can be pulled apart into fine threads, or fibers. Sometimes it is called "mineral silk." Another name for it is "cotton stone."

Asbestos fibers can be twisted or woven or molded together. They can be made into rope or cloth or paper. They can be put into plaster or paint or cement.

Shingles on houses are often made of asbestos-cement. There is no danger that a roof covered with these shingles will catch on fire from a spark. Theaters have asbes­tos curtains. If a fire breaks out on stage, the curtain can be put down to keep the fire from spreading.

Neither heat nor electricity can travel easily through asbestos. Sheets of asbes­tos are wrapped around furnace pipes to keep the heat from escaping. Asbestos fi­bers may be put between walls to shut heat in. Asbestos may also be used around wires to keep electricity from going off the path it is supposed to follow.

Asbestos makes good automobile brake bands and clutch linings. These parts have to withstand great heat. Every year thousands of miles of asbestos bands are woven or molded for automobiles.

People have known about asbestos ever since the days of the ancient Greeks. In the Middle Ages the famous emperor Charlemagne had a tablecloth made of asbestos. To clean it he threw it into a fire. The fire burned off all the grease that had been spilled on it but did not damage the cloth itself. The Chínese were making cloth of asbestos in the days of Marco Polo. In those days people thought that salamanders could live in fire. Asbestos was sometimes called "salamander's wool."