Tourmaline specimen

Robert M. Lavinsky, via Wikimedia Commons

Tourmaline

Silicates

Specimen Details

  • Hardness (Mohs): 7–7.5
  • Chemical Formula: Na(Li,Al)3Al6(Si6O18)(BO3)3(OH)3(OH)
  • Crystal System: Trigonal
  • Size: Specimen size varies; record the piece, not the species

Gem tourmaline used in jewelry is usually elbaite, a boron cyclosilicate. Rubellite is the red variety, indicolite the blue, and verdelite the green. Paraiba tourmaline is copper-bearing elbaite, not a separate species.

This page is only for Tourmaline. Comments below are for this material.

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