Steven Dutch, Professor Emeritus, Natural and Applied Sciences, University of Wisconsin - Green Bay
A sodium-bearing pyroxene of highly-alkaline igneous rocks.Mostly identified by its deep green color. May showcharacteristic 87-93 degree pyroxene cleavage.
The deep color pretty much dominates the interference colors.
Below is acmite in plane-polarixed light. Note the near right-anglepyroxene cleavage in the central grain. Pyroxene cleavage thisgood is actually fairly uncommon, and much more often seen inthin section than hand specimen.
Same field in crossed polarizers. The deep green color stillpretty much dominates, though some grains with red interferencecolors shift to orange or yellow, a blend of interference colorand natural color. Note also the lath-like plagioclase feldsparcrystals
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Created 10 Oct 1997, Last Update 16 December 1999