General Information:
Chemical Formula:
CaAL2(F,OH)8
Composition:
(Molecular Weight = 242.05 gm)
Calcium 16.56 % Ca
Aluminum 22.29 % Al
Hydrogen 0.83 % H
Oxygen 13.22 % O
Fluorine 47.09 % F
Empirical Formula:
CaAl2F6(OH)2
Locality:
St. Peter's Dome near Pike's Peak, Colorado, USA.
Name Origin:
From the Greek prosopon - "mask."
Physical Properties:
Cleavage:
[111] Perfect, [111] Perfect, [111] Perfect
Color:
white, greenish white, or reddish white.
Density:
2.88 - 2.89, Average = 2.88
Diaphaniety:
Transparent
Habits:
Crystalline - Fine - Occurs as well-formed fine sized crystals., Massive - Granular - Common texture observed in granite and other igneous rock.,
Hardness:
4-5 - Fluorite-Apatite
Luminescence:
None.
Luster:
Vitreous - Dull
Streak:
white
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