pyrophyllite

American  

[pahy-ruh-fil-ahyt, pahy-rof-uh-lahyt] / ˌpaɪ rəˈfɪl aɪt, paɪˈrɒf əˌlaɪt /

noun

1. Mineralogy. a phyllosilicate, AlSi 2 O 5 (OH), usually having a white or greenish color, and occurring in either foliated or compact masses, the latter variety being used like soapstone.

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pyrophyllite British  

/ ˌpaɪrəʊˈfɪlaɪt /

noun

1. a white, silvery, or green micaceous mineral that consists of hydrated aluminium silicate in monoclinic crystalline form and occurs in metamorphic rocks. Formula: Al 2 Si 4 O 10 (OH) 2

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Etymology

Origin of pyrophyllite

First recorded in 1820–30, pyrophyllite is from the German word Pyrophyllit; so called because it exfoliates when heated. See pyro-, -phyll, -ite ¹

Example Sentences

The following minerals, according to Griffin, produce beads with soda, but do not fuse when heated alone: quartz, agalmatolyte, dioptase, hisingerite, sideroschilosite, leucite, rutile, pyrophyllite, wolckonskoite.

From A System of Instruction in the Practical Use of the Blowpipe Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations by Anonymous