General Information: Chemical Formula:NaAlSi3O8
Composition:(Molecular Weight = 263.02 gm)
Sodium 8.30 %
NaCalcium 0.76 %
CaAluminum 10.77 %
AlSilicon 31.50 %
SiOxygen 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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