Item talk:Q41811
From geokb
Mindat Short Description
Trachytic rocks, with felsics comprising 0-5% quartz and alkali feldspar/total feldspar 0.35-0.65. Also a potassic trachyandesite where Na^2O-2.
A porphyritic extrusive rock having phenocrysts of plagioclase and potassium feldspar in nearly equal am...