Kyanite is an aluminum silicate mineral that is typically formed under high pressure during the metamorphism of clay-rich (pelitic or argillaceous) rocks. Kyanite is also found in kimberlites, which are unusual intrusive rocks that contain diamonds.
Pronunciation: KIEanite (accent on capitalized syllable)
Color: blue, sometimes white or gray
Luster: vitreous
Diaphaneity: translucent; may appear to be opaque in hand specimen
Hardness: 5 parallel to the length of the crystals and 7 perpendicular to the long direction.
Specific gravity: 3.6
Cleavage/fracture: 1 direction
Other distinguishing properties: Kyanite occurs in distinctive blue elongate tabular or bladed crystals in certain metamorphic rocks.
Klein, C., and Hurlbut, C.S., Jr., 1999, Manual of Mineralogy (after James D. Dana) [21st edition, revised]: New York, John Wiley & Sons, 682 p.
Los Angeles County Museum of Natural History, The Photo Atlas of Minerals: nhm.org/pam/ This web document was created in 2002 by Vince Cronin
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