General Information:
Chemical Formula:
Na(Al,Fe+++)Si2O6
Composition:
(Molecular Weight = 202.14 gm)
Sodium 11.37 % Na
Aluminum 13.35 % Al
Silicon 27.79 % Si
Oxygen 47.49 % O
Empirical Formula:
NaAl(Si2O6)
Environment:
Strongly metamorphosed sodium-rich serpentinous rocks
IMA Status:
Approved IMA 1987
Locality:
Clear Creek, San Benito County, California. Near Tawmaw and Hpakan villages, Upper Burma.
Name Origin:
From the Spanish, piedra de ijada, "stone of the side," because its supposed to cure kidney ailments if applied to the side of the body.
Physical Properties:
Cleavage:
[110] Good
Color:
green, white, pale bluish gray, grayish green, or pale purple.
Density:
3.25 - 3.35, Average = 3.3
Diaphaniety:
Translucent to subtranslucent
Habits:
Granular - Generally occurs as anhedral to subhedral crystals in matrix., Fibrous - Crystals made up of fibers., Massive - Fibrous - Distinctly fibrous fine-grained forms.
Hardness:
6.5 - Pyrite
Luminescence:
Non-fluorescent.
Luster:
Vitreous (Glassy)
Streak:
white
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