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
German Quarz, from Middle High German quarc, of Slavic origin.(American Heritage® Dictionary of the English Language, Fourth Edition)
German Quarz, from Middle High German twarc, probably from a West Slavic language (compare Czech tvrdý ("hard"), Polish twardy ("hard"), Russian твёрдый ("hard")), from Old Church Slavonic тврьдъ ("firm"), from Proto-Slavic *tvьrdъ. (Wiktionary)