Zircon (?), n. [F., the same word as jargon. See Jargon a variety of zircon.] 1. (Min.) A mineral consisting predominantly of zirconium silicate (Zr2SiO4) 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.[1913 Webster +PJC]
2. an imitation gemstone made of cubic zirconia.[PJC]
Zircon syenite, a coarse-grained syenite containing zircon crystals and often also elæolite. It is largely developed in Southern Norway.[1913 Webster]