Zircon
An important source of zirconium, hafnium and thorium. Quality-grade crystals are cut into genstones with green zircons being much in demand. Usually associated with acidic, igneous rocks or pegmatites. The crystals are four-sided and stubby, often perfectly transparent with good luster, but they can also be opaque and dull.
Crystal structure: Tetragonal.
Color : Colorless to yellow.