Zircon

Formula: Zr(SiO4)
May contain minor U, Th, Pb, Hf, Y/REE, P, and others.
As a Commodity: Zirconium
Colour: Colourless, yellow, grey, reddish-brown, green, brown, black
Lustre: Adamantine, Vitreous, Greasy
Hardness: 7½
Specific Gravity: 4.6 – 4.7
Crystal System: Tetragonal
Member of: Zircon Group