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1 item @ $125.00  

Montgomeryite with Robertsite

#BN47282

Montgomeryite with Robertsite

#BN47282
Availability
Sold
Size
8 x 4.5 x 4 cm - Sm Cabinet 
Formula
Ca4MgAl4(PO4)6(OH)4·12H2O (RRUFF)
Locality
Tip Top mine, Custer Co., South Dakota, United States
Tagged
phosphate , pegmatite mineral

A knockout specimen full of bright red clusters of red Montgomeryite. The Tip Top mine produced, hands down the best Montgomeryite in the world. I don't know another locality, especially a pegmatite, which has produced red Montgomeryite. These clusters are 3mm across and are composed of lath-like crystals under 1mm. It contrast well against the white matrix, which is apatite/whitlockite (or bobdownsite). Off to the side is a thick carpet of sparkly jet black Robertsite. There is a little Todorokite on the Robertsite. Exceptional specimen.

Montgomeryite

Formula
Ca4MgAl4(PO4)6(OH)4·12H2
Crystal System
Monoclinic 
Cleavage
Perfect, Indistinct, None 
Luster
Vitreous (Glassy) 
Color
colorless, yellowish, white, green, red 
Streak
white 
Class
Monoclinic - Prismatic 
Hardness

Data courtesy of Webmineral.

Collection
Dr. Buford L. Nichols Collection

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