QUARTZ
quartz
(noun) 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
Source: WordNet® 3.1
Etymology
Noun
quartz (countable and uncountable, plural quartzes)
(mineral) 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.
Synonyms
• quartz
Source: Wiktionary
Quartz, n. Etym: [G. quarz.] (Min.)
Definition: 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.
Note: The crystalline varieties include: amethyst, violet; citrine
and false topaz, pale yellow; rock crystal, transparent and colorless
or nearly so; rose quartz, rosecolored; smoky quartz, smoky brown.
The chief crypto-crystalline varieties are: agate, a chalcedony in
layers or clouded with different colors, including the onyx and
sardonyx; carnelian and sard, red or flesh-colored chalcedony;
chalcedony, nearly white, and waxy in luster; chrysoprase, an apple-
green chalcedony; flint, hornstone, basanite, or touchstone, brown to
black in color and compact in texture; heliotrope, green dotted with
red; jasper, opaque, red yellow, or brown, colored by iron or
ferruginous clay; prase, translucent and dull leek-green. Quartz is
an essential constituent of granite, and abounds in rocks of all
ages. It forms the rocks quartzite (quartz rock) and sandstone, and
makes most of the sand of the seashore.
Source: Webster’s Unabridged Dictionary 1913 Edition