from
The Collaborative International Dictionary of English v.0.48
Zircon \Zir"con\, 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 elaeolite. It is largely developed
in Southern Norway.
[1913 Webster]