schorl
rock
Also known as: iron tourmaline
Learn about this topic in these articles:
comparison with greisen
- In greisen
Greisen is closely connected with schorl, both in its mineralogical composition and in its mode of origin. Schorl is a pneumatolytic product consisting of quartz, tourmaline, and, often, white mica and thus passes into greisen. Both of these rocks frequently contain small percentages of cassiterite (tin oxide) and may be…
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