General Information:
Chemical Formula:ZnAl2O4
Composition:(Molecular Weight = 183.35 gm)Aluminum 29.43 %
AlZinc 35.66 %
ZnOxygen 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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