Alumen plumosum

The term alumen plumosum has had a long association with asbestos. Alumen (= alum) is a general term for naturally occurring hydrous alkali aluminum sulfates. These are efflorescent mineral materials of fibrous, feathery appearance. Confusion with the more durable silicate composition asbestos was not settled until 1741, by Tourneforte following a visit to asbestos deposits in Asia Minor. 

Alumen plumosum A Latin name given to the fibrous and feathery types of natural alum (hydrous alkali aluminum sulfates) and other efflorescent natural sulfates. Because of visible similarity, these materials were confused with asbestos by some early writers, and the term remained in use as a synonym of asbestos for many years. 

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See also in sourсe #XX -- [ ]

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