Z is for Zircon

Zircon:

Zircon is a zirconium silicate.  It’s name comes from Arabic for vermilion.

It is used for radiometric dating, as an opacifier in ceramics, and is one of the most refractory materials known.  (refractory means that a substance is physically stable at temperatures over 1000 degrees F.

Zircon crystals come in a number of different colors including black, yellow, brown, blue, green, golden, red, pink, and colorless.  Some colors, like brown, can be heat treated to turn blue. Colorless zircons can be used as a substitute for diamonds.