Turmaline (Na(Fe,Mn)3Al6B3Si6O27(OH,F)4)

3D Model

Tourmalines are a group of silicates whose most important species are schorlite (the most common), black in color, and elbaite, which can have different colors and is the most used as a gem. The pink or red variety is called rubelite; blue, indicolite; the colorless of acroite and the green of verdelite. The same crystal can have a color at each end and a third in the center, or a color outside and others inside. They usually form elongated, striated circles, almost always with curved faces. They can form prisms with 3, 6 or 9 faces or compact masses. They are used not only as precious stones, but also in radio and optical instruments. Brazil, Namibia and the USA are the largest producers of these minerals.