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Syenite

Syenite is a coarse-grained intrusive igneous rock of the same general composition as granite but with the quartz either absent or present in relatively small amounts. The feldspars are alkaline in character and the dark mineral is usually hornblende. Soda-lime feldspars may be present in small quantities. The term syenite was originally applied to hornblende granite like that of Syene in Egypt, from which the name is derived. Syenite is not a common rock, some of the more important occurrences being in New England, Arkansas, Montana, New York (syenite gneisses), Switzerland, Germany, and Norway.

Syenite


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