If you find a piece of granite or rhyolite, it will primarily contain quartz but may contain small amounts of biotite or hornblende which gives it a speckled appearance.

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Granite and rhyolite are both igneous rocks, primarily composed of quartz, feldspar, and mica. Biotite and hornblende can also be present in small amounts, contributing to the rock's speckled appearance.

If You Find a Piece of Granite or Rhyolite, It