What does "zircon" mean?

Zircon: 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.