A form of fine-grained quartz that is nearly transparent or has a milky translucence; it fractures conchoidally.
, author=Lee A. Groat
, volume=100, issue=2, page=128
, magazine=(American Scientist)
, passage=Although there are dozens of different types of gems, among the best known and most important are […] . (Common gem materials not addressed in this article include amber, amethyst, chalcedony , garnet, lazurite, malachite, opals, peridot, rhodonite, spinel, tourmaline, turquoise and zircon.)}}
* (noun: types of minerals) agate, chert, flint, moganite
* (adjective) conchoidal
* (adverb) conchoidally
* (noun) break, fracture, flake, shatter
* (verb) knapp, break, fracture, flake, shatter
A gemstone having bands of red sard; a variety of onyx or chalcedony.
* Bible, Revelations xxi. 20
- The fifth, sardonyx ; the sixth, sardius; the seventh, chrysolyte; the eighth, beryl; the ninth, a topaz; the tenth, a chrysoprasus; the eleventh, a jacinth; the twelfth, an amethyst.