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Formula: Ca2Be4Fe2+5(PO4)6(OH)4.6H2O
Hydrated phosphate with hydroxyl, roscherite group
Specific gravity: 2.93
Hardness: 4½
Streak: Green
Colour: Dark olive green
Environments:
Greifensteinite is a rare secondary mineral in miarolitic cavities in
lithium-rich granite pegmatites
(Webmin). Associated minerals include
schröckingerite, baylissite,
monohydrocalcite and calcite
(HOM).
Localities
At the type locality, the Greifenstein Rocks, Ehrenfriedersdorf, Erzgebirgskreis, Saxony, Germany, greifensteinite occurs in
a lithium-rich granite pegmatite,
associated with
albite, K-feldspar,
roscherite, viitaniemiite,
childrenite, quartz,
apatite, herderite,
elbaite and montmorillonite
(Minrec 35.4.351).
At the the Chickering Mine, Walpole, Cheshire County, New Hampshire, USA, greifensteinite typically forms crystal clusters to 2 mm
across in the vugs of siderite and quartz, associated
with beraunite, strunzite
and childrenite. Sprays of lathlike crystals to 0.5 mm have been identified in the
hydrothermally altered triphylite assemblage, where they are associated with
whitmoreite, ludlamite and
paravauxite
(R&M 90.5.417-418).
Griefensteinite has been reported from the Charles Davis Mine and Palermo No. 1 Mine, Groton, Grafton County,
New Hampshire, and the Chandlers Mill Quarry, Newport, Sullivan county, New Hampshire, USA. In New Hampshire it occurs
as pale green to green monoclinic crystals of less than 1 mm. The crystals generally appear hexagonal and are often
arranged in radiating groups, sometimes spheres. It and other members of the
roscherite group are relatively rare because
beryllium and phosphate are needed to form minerals of this group, and that
combination is an unusual one in New Hampshire pegmatites
(R&M 97.3.230-231}.
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