from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A light-colored igneous rock consisting essentially of alkali feldspar.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A pale igneous rock consisting mostly of potassium feldspar and plagioclase.
from the GNU version of the Collaborative International Dictionary of English
- n. 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.
from The Century Dictionary and Cyclopedia
- n. A volcanic rock exhibiting a characteristic roughness when handled.
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.
Jackson Slater lowered himself over the crumbling rim of the volcanic plug, then dropped into the cooler, shadowy dimness of a rust-colored soda trachyte rock tube.
About 55 statues are made of other stone – red scoria, basalt, or trachyte – and are smaller than the average size of 5 m.
Often, where the water flows over beds of dark grey basalt, masses of trachyte, closely resembling syenite, have formed “potholes,” and by mutual action have been worn to pebbles.
To the conglomerate and trachyte succeeded black basalt, the first dispread in layers full of bubbles, the latter forming regular prisms, placed like a colonnade supporting the spring of the immense vault, an admirable specimen of natural architecture.
He brought with him a hard white stone much resembling trachyte, and fragments of fine green jasper.
Presently the quartz made way for long lines and broad patches of a yellow-white, heat-altered clay, often revetted with iron, and passably aping the nobler rock: from one reef I picked up what appeared to be trachyte, white like that of Shaghab.
The rugged peaks of the trachyte rocks presented faint outlines on the eastern horizon; at times a few patches of snow, concentrating the vague light, glittered upon the slopes of the distant mountains; certain peaks, boldly uprising, passed through the grey clouds, and reappeared above the moving mists, like breakers emerging in the heavens.
But at a later period a wide chasm formed diagonally from south-west to north-east, through which was gradually forced out the trachyte which was to form a mountain chain.
In fact, the great plutonic action is confined to the central portion of the island; there, rocks of the trappean and volcanic class, including trachyte, basalt, and tuffs and agglomerates associated with streams of lava, have made this a land of supernatural horrors.