Sapphire

Sapphire is gem corundum (aluminium oxide), a natural mineral species, in any colour except red; red corundum is ruby. Used alone, the name normally means blue sapphire, coloured by a few hundredths of a percent of iron and titanium. So-called fancy sapphires come in violet, green, yellow, orange, pink, purple and other hues, and sapphires can also be colourless, grey, black or brown.