General Information:
Chemical Formula:
NaAlSi3O8
Composition:
(Molecular Weight = 263.02 gm)
Sodium 8.30 % Na
Calcium 0.76 % Ca
Aluminum 10.77 % Al
Silicon 31.50 % Si
Oxygen 48.66 % O
Empirical Formula:
Na0.95Ca0.05Al1.05Si2.95O8
Environment:
Magmatic and pegmatitic rocks.
Locality:
TL: USA, VA, Amelia. Bourg d'Oisans and Isere, France.
Name Origin:
From the Latin, albus, in allusion to the common color.
Physical Properties:
Cleavage:
[001] Perfect, [010] Good
Color:
white, gray, greenish gray, bluish green, or gray.
Density:
2.61 - 2.63, Average = 2.62
Diaphaniety:
Transparent to translucent to subtranslucent
Habits:
Blocky - Crystal shape tends to be equant (e.g. feldspars)., Striated - Parallel lines on crystal surface or cleavage face., Granular - Generally occurs as anhedral to subhedral cryst als in matrix.
Hardness:
7 - Quartz
Luminescence:
None.
Luster:
Vitreous (Glassy)
Streak:
white
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