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RHYOLITE   (detail)

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Another specimen

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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).
Detail Description
     In this detail no crystals can be seen (except for a few small fragments) indicating the rapid cooling history of this rock. For comparison look at this alkali granite (magnified about the same - see penny) where the crystals are clear and obvious (hit the "Back" button to get back here.)
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Last Update: 9/29/00

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