General Information:
Chemical Formula:CaAl2Si4O12·4(H2O)
Composition:(Molecular Weight = 470.44 gm)Calcium 8.52 %
CaAluminum 11.47 %
AlSilicon 23.88 %
SiHydrogen 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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