ZIRCON
zircon, zirconium silicate
(noun) a common mineral occurring in small crystals; chief source of zirconium; used as a refractory when opaque and as a gem when transparent
Source: WordNet® 3.1
Etymology
Noun
zircon (countable and uncountable, plural zircons)
(uncountable) A mineral occurring in tetragonal crystals, usually of a brown or grey colour and consisting of silica and zirconia.
(countable) A crystal of zircon, sometimes used as a false gemstone.
Source: Wiktionary
Zir"con, n. Etym: [F., the same word as jargon. See Jargon a variety
of zircon.] (Min.)
Definition: A mineral occurring in tetragonal crystals, usually of a brown
or gray color. It consists of silica and zirconia. A red variety,
used as a gem, is called hyacinth. Colorless, pale-yellow or smoky-
brown varieties from Ceylon are called jargon. Zircon syenite, a
coarse-grained syenite containing zircon crystals and often also
elæolite. It is largely developed in Southern Norway.
Source: Webster’s Unabridged Dictionary 1913 Edition