General Information:
Chemical Formula:
Ca3Fe+++2(SiO4)3
Composition:
(Molecular Weight = 508.18 gm)
Calcium 23.66 % Ca
Iron 21.98 % Fe
Silicon 16.58 % Si
Oxygen 37.78 % O
Empirical Formula:
Ca3Fe2+2(SiO4)3
Environment:
Igneous and metamorphic rocks.
Locality:
Magnet Cove, Arkansas.
Name Origin:
Andradite is named after the Brazilian mineralogist J. B. de Andrada e Silva (1763-1838). Demantoid is named after its adamantine luster.
Physical Properties:
Cleavage:
None
Color:
black, yellowish brown, red, greenish yellow, or gray.
Density:
3.7 - 4.1, Average = 3.9
Diaphaniety:
Transparent to translucent
Habits:
Crystalline - Coarse - Occurs as well-formed coarse sized crystals., Euhedral Crystals - Occurs as well-formed crystals showing good external form., Massive - Uniformly indistinguisha ble crystals forming large masses.
Hardness:
6.5-7 - Pyrite-Quartz
Luminescence:
None.
Luster:
Vitreous (Glassy)
Streak:
white
More details...