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Jahnsite-(Camnmg) with Rockbridgeite & Hureaulite

#57261

Jahnsite-(Camnmg) with Rockbridgeite & Hureaulite

#57261
Availability
Sold
Size
4.5 x 1.5 x 2 cm - Miniature 
Formula
CaMn2+Mg2Fe3+2(PO4)4(OH)2·8H2O (RRUFF)
Locality
Tip Top mine, Custer Co., South Dakota, United States
Tagged
phosphate , pegmatite mineral

A complicated specimen loaded with many minerals. The main mineral is nut brown, striated Jahnsite-(CaMnMg). This is the original Jahnsite prior to the breakout of additional Jahnsites based upon the major elements occupying the structural sites. This particular Jahnsite is about the only one that you can visually identify at the Tip Top. The rest aren't necessarily identified easily based upon color. There is another Jahnsite on this specimen, which is yellow and much smaller. Additionally there is black, acicular Rockbridgeite & pink Hureaulite crystals. The Hureaulte is about 2mm and is pink with yellow Jahnsite on the surface and pseudomorphing. There is also purple Leucophosphite.

Jahnsite-(CaMnMg)

Formula
CaMn2+Mg2Fe3+2(PO4)4(OH)2·8H2
Crystal System
Monoclinic 
Cleavage
Good, None, None 
Luster
Vitreous - Adamantine 
Color
brown, purplish brown, yellow, yellow orange, greenish yellow 
Streak
white 
Class
Monoclinic - Prismatic 
Fracture
Brittle 
Hardness

Data courtesy of Webmineral.

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