from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A very hard mineral composed of silica, SiO2, found worldwide in many different types of rocks, including sandstone and granite. Varieties of quartz include agate, chalcedony, chert, flint, opal, and rock crystal.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The most abundant mineral on the earth's surface, of chemical composition silicon dioxide, SiO2. It occurs in a variety of forms, both crystalline and amorphous. Found in every environment.
from the GNU version of the Collaborative International Dictionary of English
- n. A form of silica, or silicon dioxide (SiO2), occurring in hexagonal crystals, which are commonly colorless and transparent, but sometimes also yellow, brown, purple, green, and of other colors; also in cryptocrystalline massive forms varying in color and degree of transparency, being sometimes opaque.
from The Century Dictionary and Cyclopedia
- n. The common form of native silica, Or the oxid of silicon (SiO2).
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. colorless glass made of almost pure silica
- n. a hard glossy mineral consisting of silicon dioxide in crystal form; present in most rocks (especially sandstone and granite); yellow sand is quartz with iron oxide impurities
In addition to amethyst and citrine quartz we have the pinkish, milky quartz known as "_rose quartz_."
Of course the yellow quartz should be sold under the proper name, _citrine quartz_.
He called some well-characterized species of _septaria_ in my cabinet _pudding-stone, _ beautiful specimens of limpid hexagonal crystals of quartz, _common quartz_, &c.Mr. George P. Marsh, of Vermont, brings me a letter of introduction.
You find tin wherever you like to cut down to one kind o 'rock as is what they call quartz, and where there's tin in it there's a lot o' red powder as well; and when you break a bit there's the tin, all in pretty little black shiny grains.
Then the reefs and ledges were attacked; crushing machinery was erected, and the form of work which you call quartz mining in America had its beginning.
Say two hundred in quartz an 'dirt — that leaves two hundred pounds of gold.
He had had experience in quartz-mining before he went to Alaska, and he enjoyed the recrudescence of his old wisdom in such matters.
He had had experience in quartz-mining before he went to
Say two hundred in quartz an 'dirt -- that leaves two hundred pounds of gold.
Very good-humouredly the naturalist left Mr. Haye and came to them, and presently was deep in quartz and silica, and onyx and chalcedony, and all manner of stones that are precious.