Mica fish
Mica fish are lenticular, elongate lozenge, parallelogram-shaped, or lens-shaped (so roughly fish-shaped) single mica crystals that are often used as shear sense indicators.[1] They commonly occur in micaceous quartzitic mylonites. They characteristically lie with their longest dimension at a small angle to the mylonitic foliation.
References
This article is issued from Wikipedia - version of the 9/8/2013. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.