Home » Minerals » Tourmaline

Tourmaline


Mineral Properties and Uses



Physical Properties of Tourmaline

Chemical Classification silicate
Color bluish black, black, yellow, pink, blue, green, colorless, red
Streak colorless, gray
Luster vitreous
Diaphaneity transparent to nearly opaque
Cleavage poor
Mohs Hardness 7 to 7.5
Specific Gravity 3 to 3.3
Diagnostic Properties lack of cleavage, color
Chemical Composition (Ca,K,Na,[])(Al,Fe,Li,Mg,Mn)3(Al,Cr, Fe,V)6
(BO3)3(Si,Al,B)6O18(OH,F)4
Crystal System hexagonal
Uses gemstone


Tourmaline beads
The variety in tourmaliine color is shown with this strand of beads.


Tourmaline cabs
Numerous cabochons of tourmaline from Africa. Each gem is approximately 6 millimeters by 4 millimeters.


Tourmaline gemstone
A cut piece of tourmaline. The gemstone is approximately 1.8 carats, and 9 millimeters by 7 millimeters.


Tourmaline teardrop cab
A teardrop cabochon of tourmaline from San Diego, California. The gemstone is approximately 1.4 carats, and 9 millimeters by 5 millimeters.



Find it on Geology.com




More from Geology.com


strontium titanate
Strontium Titanate is a man-made diamond simulant with a fire much stronger than diamond.
Organic Gems
Organic Gems are gems formed from or by plants or animals. They might also be fossils.
Tanzanite
Tanzanite was unknown until a few decades ago but it has erupted into wide popularity.
Ammolite
Ammolite is a fossil and a gemstone. It is shell material from fossil ammonites.
Chrome Diopside
Diopside - Gem material, ornamental stone, diamond indicator, industrial mineral
What Is The Moho?
What Is The Moho? Learn about the interior of the Earth and the Mohorovicic Discontinuity.
Maw Sit Sit
Maw Sit Sit is a metamorphic rock and a gem material that was once thought be jade.
Natural Gas Investing
Natural Gas Investing Kenny DuBose wants you to ask: Why did this deal come my way?


Tourmaline crystals
Colorful gem-quality tourmaline crystals from Brazil showing the typical prismatic habit with striations. Image © iStockphoto and MarcelC.




Tourmaline in granite
Tourmaline in granite from Stoneham, Maine. Specimen is approximately 5 inches (12.7 centimeters) across.


Tourmaline
A close-up of tourmaline from Pierrepont, New York. The overall specimen is approximately 4 inches (10 centimeters) across.


Tourmaline from NY
Tourmaline from Pierrepont, New York. Specimen is approximately 3 inches (7.6 centimeters) across.


Tourmaline in microcline
Tourmaline in microcline from Bathurst, Ontario, Canada. Specimen is approximately 3 inches (7.6 centimeters) across.


More Minerals
  Minerals
  Fluorescent Minerals
  Quartz
  The Streak Test
  Hand Lens
  Diopside
  Diamond
  Mineral Identification Chart




© 2005-2016 Geology.com. All Rights Reserved.
Images, code, and content on this website are property of Geology.com and are protected by copyright law.
Geology.com does not grant permission for any use, republication, or redistribution.
Images, code and content owned by others are marked on the pages where they appear.