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Mineralpedia Details for Sinkankasite

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Sinkankasite

Sinkankasite

Named after American author and bibliographer of mineral- and gem-related subjects as well as mineral artist, Dr. John Sinkankas. Found in just two localities worldwide, Sinkankasite is “a late-stage hydrothermal alteration product of triphylite in complex zoned granite pegmatites, and can be found at its type locality at the Baker-Ferguson mine here in the Black Hills, South Dakota and at the Palermo No.3 (or Palermo No.1, according to midat.org) mine in New Hampshire, USA.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/sinkankasite.pdf

Formula
Mn2+Al(PO3OH)2(OH)ยท6H2
Crystal System
Triclinic 
Crystal Habit
Pseudomorphous 
Cleavage
Good, Parting, None 
Luster
Vitreous - Dull 
Color
colorless, white 
Streak
white 
Class
Triclinic - Pinacoidal 
Fracture
Brittle 
Hardness
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Sinkankasite from Barker-Ferguson mine, Pennington Co., South Dakota, United States

Sinkankasite
            from Barker-Ferguson mine, Pennington Co., South Dakota, United States

White, thin bladed crystals to about 0.75mm in sprays in vugs.

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