Tourmaline is a gemstone and mineral that comes in a wide range of colors and has many interesting properties:
Color
Tourmaline can be found in many colors, including red, pink, yellow, brown, black, green, blue, or violet. Some varieties can have two or more colors in the same stone.
Crystal structure
Tourmaline is a member of the trigonal crystal system, which means its crystals have a slightly rounded 3-sided cross section.
Hardness
Tourmaline has a hardness of 7.5 on the Moh's scale, making it hard enough to be used as a gemstone.
Pyroelectricity
Tourmaline is pyroelectric, meaning it becomes electrically charged when heated or squeezed.
Birthstone and anniversary gem
Tourmaline is the birthstone for October and the gem for the eighth anniversary.
Name
The name tourmaline comes from an ancient Sinhalese word that means "a mixed color precious stone" or "something small from the earth".
Uses
Some tribes in Africa, Native Americans, and aboriginal groups in Australia use tourmaline as a talisman that protects against all dangers.
Chrome tourmaline
Chrome tourmaline is a tourmaline that is close in color to emerald, but is often darker and rarer.
Mined, uncut Tourmaline.