No other stone is as sophisticated as Tourmaline; like garnet, it is a group of gemstones comprising several species and not a single one with several varieties, such as quartz. Vitreous, transparent to opaque, there are more than 100 colors: deep green, red, blue, yellow, brown, black, and colorless. Besides its wide variety of colors, one of the most striking features of these gems is that you can see two or more colors in the same crystal.