• Exhibition Text

    • This rock was once a granite.  As it was deformed by heat and pressure, the original even-grained rock developed dark layers, primarily biotite, and light layers, mostly gray quartz, pink orthoclase, and black hornblende.

      AMNH collection

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  • For Educators

    • Topic: Earth Science

      Subtopic: Minerals and Resources

      Keywords: Gneiss, Geology, Minerals, Granite

      Audience: General