noun. A light-colored igneous rock consisting essentially of alkali feldspar.

noun. A volcanic rock exhibiting a characteristic roughness when handled.

noun. An igneous rock, usually light gray in color and breaking with a rough surface. It consists chiefly of orthoclase feldspar with sometimes hornblende and mica.

noun. A pale igneous rock consisting mostly of potassium feldspar and plagioclase.

"The +Puy-de-Dome+ is 4806 ft. above the level of the sea, has no crater, and is covered with a long tufted grass, with here and there a rough spongy rock cropping out, of volcanic origin, and called trachyte, of which the variety found here, and almost here alone, has been named domite."

acmite-trachyte  greenstone-trachyte  quartz-trachyte  

trachytic  trachytoid  

4-4-2  andesite  augite  backbone  basalt