Crossword clues for pyrophyllite
The Collaborative International Dictionary
Pyrophyllite \Py*roph"yl*lite\, n. [Pyro- + Gr. ? leaf.] (Min.) A mineral, usually of a white or greenish color and pearly luster, consisting chiefly of the hydrous silicate of alumina.
Wiktionary
n. (context mineral English) A soft, pale aluminosilicate mineral, somewhat resembling talc.
WordNet
n. a white or greenish aluminum silicate mineral (resembles talc)
Wikipedia
Pyrophyllite is a phyllosilicate mineral composed of aluminium silicate hydroxide: AlSiO(OH). It occurs in two more or less distinct varieties, namely, as crystalline folia and as compact masses; distinct crystals are not known.
The folia have a pronounced pearly luster, owing to the presence of a perfect cleavage parallel to their surfaces: they are flexible but not elastic, and are usually arranged radially in fan-like or spherical groups. This variety, when heated before the blowpipe, exfoliates and swells up to many times its original volume, hence the name pyrophyllite, from the Greek pyros (fire) and phyllos (a leaf), given by R. Hermann in 1829. The color of both varieties is white, pale green, greyish or yellowish; they are very soft ( hardness of 1 to 1.5) and are greasy to the touch. The specific gravity is 2.65 - 2.85. The two varieties are thus very similar to talc.
Usage examples of "pyrophyllite".
This pyrophyllite is a quite soft secondary mineral with a count of only 3 on the Mohs scale and was formed by sedimentation about 2.
They are found in pyrophyllite, which is mined near the little town of Ottosdal in the Western Transvaal.