Dark brown dravite tourmaline crystal with sharp terminations from the USA.
Macro view of parallel growth striations on brown dravite crystal, USA.
Close-up of a dark brown dravite tourmaline crystal with matrix, USA.

Tourmaline var. Dravite

Tourmaline – Na(Li,Al)3Al6Si6O18(BO3)3(OH)4
Elements: Sodium, Lithium, Aluminum, Silicon, Oxygen, Boron, Hydrogen
Class: Silicates – Cyclosilicates
Crystal System: Hexagonal
Hardness: 7-7.5
Quartz
Talc (1)Diamond (10)
Very hard. Scratches glass and steel.
Dravite – NaMg3Al6(Si6O18)(BO3)3(OH)3(OH)
Elements: Sodium, Magnesium, Aluminum, Silicon, Oxygen, Boron, Hydrogen
Class: Silicates – Cyclosilicates
Crystal System: Triclinic
Hardness: 7
Quartz
Talc (1)Diamond (10)
Very hard. Scratches glass and steel.
Origin: Power’s Farm, Pierrepont, St Lawrence Co., New York – Usa
Did you know?

For a few years, San Diego County mined pink stones mostly for one customer on the other side of the world. Between 1902 and 1910 the mines shipped some 120 tons of gem rubellite to imperial China to feed the Empress Dowager Cixi's love of the color, and when she died and the Qing dynasty fell soon after, the market collapsed and the California boom went with it.

More Silicates

Emerald green dioptase crystal cluster displaying full vertical mirror reflection
Dioptase
White acicular mesolite needles on green apophyllite with mirror reflection.
Mesolite on Apophyllite
Pale purple spirit quartz cluster from South Africa with mirror reflection.
Quartz (Cactus var. Amethyst)
Deep red zincite specimen with pale green willemite vein on black background.
Zincite & Willemite
Black botryoidal heterogenite specimen from Congo with green chrysocolla spots.
Heterogenite & Chrysocolla
Uvarovite Garnet (Large)Cylindrite