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Sincosite

#34550

Sincosite

#34550
Availability
Sold
Size
5 x 4 x 3 cm - Miniature 
Formula
Ca(V4+O)2(PO4)2·5H2O (RRUFF)
Locality
Ross Hannibal mine, Lawrence Co., South Dakota, United States
Tagged
phosphate

Green tabular crystals of Sincosite to 2mm with a white spray of Minyulite from the 1996 find in the Black Hills. Not too many of these are left. Sincosite was first found in the early 1920's in the phosphatic black shales of Sincos, Peru, thus the name. It was also found in the 1890's at the Ross Hannibal mine, but was thought to be Torbernite. Much later a specimen from Bryn Mawr college was reanalyzed and the true identity was made. In 1996, the Sincosite deposit was rediscovered during open pit mining the old Ross Hannibal workings. The Ross Hannibal was mined in a phosphate-rich zone within the lower Cambrian Deadwood fm. This specimen is from that find. You can read all about it in the Min. Record May/June 1990 issue. A copy of that article will be sent with this specimen.

Sincosite

Formula
Ca(V4+O)2(PO4)2·5H2
Crystal System
Tetragonal 
Crystal Habit
Scaly, Platy, Aggregates 
Cleavage
Perfect, Distinct, Poor 
Luster
Vitreous - Metallic 
Color
green, yellowish green, olive green, brownish green 
Streak
light green 
Class
Tetragonal 
Fracture
Brittle 
Hardness
1-2 

Data courtesy of Webmineral.

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