General Information:
Chemical Formula:
ZnAl2O4
Composition:
(Molecular Weight = 183.35 gm)
Aluminum 29.43 % Al
Zinc 35.66 % Zn
Oxygen 34.90 % O
Empirical Formula:
ZnAl2O4
Environment:
Metamorphic and pegmatitic rocks.
Locality:
Falun, Sweden.
Name Origin:
Named after the Swedish chemist and mineralogist, J. G. Gahn (1745-1818).
Physical Properties:
Cleavage:
[111] Indistinct
Color:
bluish green, grayish green, deep leek green, greenish black, or bluish black.
Density:
4 - 4.6, Average = 4.3
Diaphaniety:
Subtransparent to opaque
Habits:
Euhedral Crystals - Occurs as well-formed crystals showing good external form., Massive - Granular - Common texture observed in granite and other igneous rock., Striated - Parallel li nes on crystal surface or cleavage face.
Hardness:
8 - Topaz
Luminescence:
None.
Luster:
Vitreous (Glassy)
Streak:
gray
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