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 geode of chalcedony containing trapped water.
* 1875 : William Whitaker, B.A., F.G.S., ed, The Geological Record for 1874: An Account of Works on Geology, Minerology, and Palæontology published during the year
- ... the liquid obtained from the cavities of a specimen of ''enhydros'' , or "water-stone." It consists of clear water containing in solution a small proportion of certain salts, apparently the chlorides and sulphates of sodium, magnesium, and calcium.