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Typical Minerals
Minerals too small to identify (except phenocrysts). Composition will be from bottom of Bowen's Reaction series (i.e. felsic).
     A fine grained (aphanitic) igneous rock, white, light gray, pink, to dark in color. Phenocrysts (large visible crystals) are often present, such as in this specimen (although the larger chunks may be pyroclastics, volcanic ejecta, rather than true phenocyrsts.)
      Since color is such a poor indicator of rock identification in most cases, darker rhyolites can be confused with lighter andesites. Felsite is the general term for an unidentifiable, fine grained, generally middle colored rock.
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Tectonic Association
     Rhyolite, as with all felsic rocks, is found on continents, ejected from volcanoes.
   Tectonic Cross Section - pdf version

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