What is Asbestos?

The word asbestos comes from the Greek word meaning unquenchable or indestructible. Asbestos is a naturally occuring mineral that is fiber forming, flame resistant, and has indestructible qualities. Asbestos resists fire, friction and chemicals. 

The Industrial 'boom' created a demand for a low cost and abundant material that was indestructible with good insulating properties, the answer was Asbestos. Asbestos was useful for electrical, acoustical and thermal insulation. Asbestos usage can be found in the schools, workplace and home.

From the beginning of the 1900's, tens of millions of tons of asbestos, in various mineral forms have been quarried and utilized for an enormous range of purposes, which include the production of asbestos cement, manufactured products for building industry, and pipes; the insulation of buildings and the means of tranportation by both land and sea; the construction of brakes, etc.

Image of Asbestos Street, Prieska, South Africa by Hein du Plessis, 1999

Asbestos appealed to manufacturers and builders for a variety of reasons. It is strong yet flexible, and it will not burn. It conducts electricity poorly, but insulates effectively. It also resists corrosion. Asbestos was so widely used because so few other available substances combined the same qualities. Asbestos was primarily used as a binder in everything from floor tile, adhesive, plaster to pipe insulation, it has been estimated that there are about 3,000 uses for asbestos.

In the United States commercial use began in the 1900's and had a growth increase in the 1940-50's and peaked in the early1970's. The asbestos industry peaked in 1973 with Canada furnishing 95% of all imported raw asbestos. 

Physical Characteristics

Asbestos minerals occur in fibrous form, have varying degrees of heat resistance, tensile strength and electrical conductivity. However, the minerals are not identical in chemical composition, crystal structure or geologic distribution. Asbestos is broken into two mineral groups: Serpentine and Amphiboles. The Serpentine group consist of the asbestos mineral chrysotile. The Amphibole group consists of the asbestos minerals amosite, crocidolite, tremolite, actinolite and anthophyllite.

One of the distinctions between the two groups is the characteristic of the fibers. Chrysotile is curly and usually occurs in bundles. Amphiboles are straight and needle-like. Color is another distinction. Chrysotile is white, amosite is brown and crocidolite is blue.

The amphiboles may be refered to as the 'brittle asbestos' because of its tendancy to break and therefore could not be woven unlike chrysotile. However, the amphiboles such as amosite and crocidolite, were still mixed with binder. Because of its strength and flexibility, chrysotile became the most common form of asbestos with 90-95% of the asbestos-containing products containing chrysotile. Amosite is the asbestos variety primarily found in South Africa. The first four letters of 'amos'ite is derived from AMOSA which was the acronym for Asbestos Mines of South Africa. Crocidolite is highly chemical resistant and was used in gas mask canisters during World War II. Tremolite, actinolite and anthophyllite had minor commercial significance and often appear as impurity in materials rather than an additive.

Images of Chrysotile and Amosite (Cummingtonite-Grunerite) from Selected Silicate Minerals and Their Asbestiform Varieties. U. S. Dep. of the Interior, Bureau of Mines Information Circular, IC8751, 1977

Geological Occurence

Asbestos forms in vein structures in the parent rock. Several factors and geologic process occur to transform asbestos such as temperature and pressure or the hot mineral solutions. Deposits of asbestos are quite widely distributed but in many instances the vein of asbestos is so thin that the fibers which run perpendicular to the vein are to short to be of practical value. For this very reason is why Canada with asbestos veins ocurring thickness from 1/2 inch to 4-1/2 inches is the principle source for asbestos. Other large deposits occur in Italy, South Africa and Russia.

Vein of white Chrysotile asbestos in parent rock green Serpentine

Deposits of asbestos can be found throughout the United States of these deposits on five are commercially viable and the mines are located in only three states: California, Arizona and Vermont.

History of Usage

Asbestos was used throughout history. First with prehistoric time to strengthened earthernware then in ancient Greek time as lamp wicks and finally with the Romans for cremation cloth. One of the earlier and more notable (and possibly mythical see Charlemagne's Tablecloth by Nicola Fletcher) uses was as an asbestos tablecloth which Charlemagne used to entertain and mystify guests by throwing the tablecloth into the flames where it most assuredly should be consumed only to pull it out and have it not only be intact but clean and white. During these early years asbestos remained a curiosity it was not until the late 1800's did the unique qualities of asbestos begin to find its application into everyday life.

The first modern applications began to appear in the 1860-70's as roof coating and pipe insulation. With the opening of the first Italian mine 1866 and the first Canadian mine 1877 asbestos became available for more than just curiosities. By the early 1900's several industries have sprouted from the manufactured of asbestos-containing products such as asbestos-cement pipes and brake linings.

The demand for asbestos was never greater than during World War II. The demand was a result of both the need for the material in manufactured materials such as corrugated asbestos-cement sheets for aircraft hangers and pipe insulation and friction materials for the Navy's ships and the fact that ships hauling asbestos from South Africa were be sunk.

The demand for the long asbestos fibers for textiles and insulation during the war left a post-war surplus of asbetos short fibers and an industry looking to for a new market. The post-war building boom gave the industry the market it desired and subsequently asbestos was popping in a myriad of construction materials. Roofing, siding, flooring, piping, wall board, ceiling tiles all touting the safety enhancements of a product made with asbestos.

Read these Guides for further information on the myriad of materials made with asbestos and where to find them including on eBay. 

View all my other ASBESTOS GUIDES