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Robertsite
Type Locality
Tip Top Mine (Tip Top pegmatite), Fourmile, Custer District, Custer Co., South Dakota, USA
Mineral Data
Ca
3
Mn
3+
4
(PO
4
)
3
O
2
·3H
2
O
Strunz:
8.DH.30
Physical Properties
Streak:
Red-brown
Hardness:
3.5
Tenacity:
waxy
