Fluorite

Fluorite 

Fluorite is the mineral form of calcium fluoride, CaF₂. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 4 as fluorite. Wikipedia
Color: Green, Blue, White, Black, Purple, Yellow, Red, Pink, Orange, Brown
Luster: Vitreous
Crystal system: Cubic crystal system
Chemical formula: CaF₂
Hardness (Mohs hardness scale): 4
Transparency: Translucent, Transparent