from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A dark-green to black pyroxene mineral, (Ca,Na)(Mg,Fe,Al)(Si,Al)2O6, that contains large amounts of aluminum, iron, and magnesium.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A variety of pyroxene, usually of a black or dark green color, occurring in igneous rocks, such as basalt.
from the GNU version of the Collaborative International Dictionary of English
- n. A variety of pyroxene, usually of a black or dark green color, occurring in igneous rocks, such as basalt; -- also used instead of the general term pyroxene.
from The Century Dictionary and Cyclopedia
- n. The dark-green to black variety of pyroxene characteristic of basic eruptive rocks like basalt.
- n. The name of this member of the pyroxene group of silicate minerals is frequently used in petrography in composition with the name of any rock in which it occurs as a prominent or noteworthy constituent: as, augite-andesite, augite-syenite, augite-gneiss, etc.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. dark-green to black glassy mineral of the pyroxene group containing large amounts of aluminum and iron and magnesium
Below this were strata of trachitic breccia and augite; the formation was then seamy to an unknown depth.
Taken, then, a liquid which is heavy -- the most convenient is methylene iodide, whose specific gravity is 3.3 -- a fragment of zircon will sink in this, and a fragment of tourmaline will float, but a fragment of the mineral augite, whose specific gravity is also 3.3, will remain exactly suspended.
They are divisible into two great classes, which have received the names of diorite and dolerite, the former a mixture of albite and hornblende, the latter of augite and labradorite, sometimes with considerable quantities of a sort of oligoclase containing both soda and lime, and of different kinds of zeolitic minerals.
With the exception of quartz and augite, these names are, however, representatives of different classes of minerals.
Their number is by no means large, and they all consist of mixtures in variable proportions of quartz, felspar, mica, hornblende, augite, and zeolites.
Hornblende and augite are two widely distributed minerals, which are so similar in composition and properties that they may be considered together.
Dolerite, when composed entirely of augite and labradorite, produces rather inferior soils; but when it contains oligoclase and zeolites, and comes under the head of basalt, its disintegration is the source of soils remarkable for their fertility; for these latter substances undergoing rapid decomposition furnish the plants with abundant supplies of alkalies and lime, while the more slowly decomposing hornblende affords the necessary quantity of magnesia.
In the Jerome or Verde district of central Arizona, folded pre-Cambrian greenstones and sediments were invaded by masses of quartz-porphyry, and after further deformation, rendering many of the rocks schistose, were intruded by an augite-diorite.
"So you don't know the difference between augite and hornblende?" he once enquired.
Pyroxene, quartz and augite form the groundmass, as seen in section.