The countertop has quartz, plagioclase feldspar, potassium feldspar and biotite ... Hornblende (brown) with dark reaction rims in plain (singly) polarized light from a sample of rhyolite from ...

The countertop has quartz, plagioclase feldspar, potassium feldspar and biotite ... Hornblende (brown) with dark reaction rims in plain (singly) polarized light from a sample of rhyolite from Edison ...