General Information:
Chemical Formula:
CaAl2Si4O12·4(H2O)
Composition:
(Molecular Weight = 470.44 gm)
Calcium 8.52 % Ca
Aluminum 11.47 % Al
Silicon 23.88 % Si
Hydrogen 1.71 % H
Oxygen 54.42 % O
Empirical Formula:
CaAl2Si4O12·4(H2O)
Environment:
Secondary mineral in basalts and andesites. Also occurs in metamorphic rocks and granites. Found in copper veins.
IMA Status:
Approved IMA
Locality:
Nagy-Ag, Transylvania of Romania.
Name Origin:
Named after the Frenchman, F. P. N. de Laumont (1747-1834).
Physical Properties:
Cleavage:
[010] Perfect, [110] Perfect
Color:
brownish, gray, yellowish, pearl white, or pink.
Density:
2.25 - 2.35, Average = 2.29
Diaphaniety:
Transparent to translucent to opaque
Habits:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Crystalline - Fine - Occurs as well-formed fine sized crystals., Bladed - Aggregates of thin lath-like crystals (e. g. kyanite).
Hardness:
3.5-4 - Copper Penny-Flourite
Luminescence:
None.
Luster:
Vitreous (Glassy)
Streak:
white
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