Magnesium tourmaline

Magnesia tourmaline is a brown tourmaline rich in magnesium. Name: magnesium tourmaline is named after its Drava River, Austria.
Chemical composition: the minerals of this group contain B, and some of the cations are common in isomorphism. It also contains a small amount of Cr3+, V3+, Ti4+, and K+. The additional anions are mainly (OH) - mainly, but F-.
Category: silicate mineral - cyclic silicate mineral tourmaline family.
Crystal system and space group: three square system, R3m.
Cell parameters: a0=1.594nm, c0=0.722nm.
Morphology: single crystal is short columnar, long columnar or even needle like, and there are always longitudinal patterns on the cylinder. The aggregate is radial or fibrous, and in a few cases it is lumpy or granular.
Color: colorless to dark black.
Mark: the same.
Transparency: transparent to translucent.
Luster: Glass luster.
Cleavage and fracture: no cleavage.
Other properties: the transverse section is arc triangle because of the longitudinal lines on the cylinder; the identification features are columnar shape, the column has longitudinal lines, and the transverse section is arc triangle, without cleavage and high hardness.
Main uses: the transparent color beauty is used as the gem.