Quartz diorite is an igneous, plutonic (intrusive) rock, of felsic composition, with phaneritic texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with 10% or less potassium feldspar. Quartz is present at between 5 to 20% of the rock. Biotite, amphiboles and pyroxenes are common dark accessory minerals.
- Williams, Howel; Francis J. Turner and Charles M. Gilbert (1954) Petrography, W. H. Freeman
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