Augen

Augen (from German `eyes`) are large, lenticular eye-shaped mineral grains or mineral aggregates visible in some foliated metamorphic rocks. In cross section they have the shape of an eye. Feldspar, quartz, and garnet are common minerals which form augen. Augen form in rocks which have undergone metamorphism and shearing. The core of the augen i.....
Found on http://en.wikipedia.org/wiki/Augen
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