White, apple-green, gray powder; pearly
or greasy luster, greasy feel. Mohs hardness 1–1.5
(may be harder when impure), high resistance to
acids, alkalies, and heat.
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Chiefly as a ceramic insulator in electronic
devices.
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A natural hydrous magnesium silicate. Compact,
massive varieties may be called steatite in distinction
from the foliated varieties, which are called
talc. Soapstone is an impure variety of steatite.
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Toxic by inhalation. Effects pulmonary
function and causes pulmonary fibrosis. Questionable
carcinogen.
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The fibrous talc in soapstone
dust causes fibrotic pneumoconiosis; an increased
incidence of cancer of the lungs and
pleura has been reported.
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Steatites are noted for their excellent electricalproperties and low cost. They are easily formedand fired at relatively low temperatures. However,compositions containing little or no clayor plastic material present fabricating problemsbecause of a narrow firing range. Steatite partsare vacuum-tight, can be readily bonded toother materials, and can be glazed or ground tohigh-quality surfaces.
