General Information:
Chemical Formula:
Al2SiO5 = Al[6]Al[5]OSiO4
Composition:
(Molecular Weight = 162.05 gm)
Aluminum 33.30 % Al
Silicon 17.33 % Si
Oxygen 49.37 % O
Empirical Formula:
Al2SiO5
Environment:
Metamorphosed peri-aluminous sedimentary rocks.
Locality:
Andalucia (Spain), an early but now unimportant location.
Name Origin:
Named after its locality.
Physical Properties:
Cleavage:
[110] Distinct, [100] Indistinct, [010] Poor
Color:
dark green, gray, brown, red, or green.
Density:
3.13 - 3.17, Average = 3.15
Diaphaniety:
Transparent to translucent
Habits:
Blocky - Crystal shape tends to be equant (e.g. feldspars)., Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Euhedral Crystals - Occurs as well-formed crystals sho wing good external form.
Hardness:
6.5-7 - Pyrite-Quartz
Luminescence:
None.
Luster:
Vitreous (Glassy)
Streak:
white
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