zircon

A brown to colorless mineral, ZrSiO₄, which is heated, cut, and polished to form a brilliant blue-white gem.

A mineral occurring in tetragonal crystals of adamantine luster and yellowish to brownish or reddish color: its hardness is somewhat greater than that of quartz.

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.

an imitation gemstone made of cubic zirconia.

a coarse-grained syenite containing zircon crystals and often also elæolite. It is largely developed in Southern Norway.

A mineral occurring in tetragonal crystals, usually of a brown or grey colour and consisting of silica and zirconia.

A crystal of zircon, sometimes used as a false gemstone.

a common mineral occurring in small crystals; chief source of zirconium; used as a refractory when opaque and as a gem when transparent