What is Dravite?
Dravite is the sodium-magnesium tourmaline end-member, usually brown to black and important for understanding the compositional range of the tourmaline group.
Mineralogy and structure
The reference formula is NaMg3Al6(BO3)3Si6O18(OH)4. Dravite has the trigonal tourmaline structure with channels along the c axis. It is a mineral species, while brown tourmaline in trade may not have been analysed to end-member composition.
Colour and appearance
Typical colours include brown, black, yellow-brown, green-brown. Its prismatic, columnar, granular habit and vitreous lustre are useful descriptive features, but colour alone is not diagnostic.
Formation and localities
Dravite forms in or is associated with magnesium-rich metamorphic rocks, marbles, schists and hydrothermal veins. Important documented localities include Slovenia, Austria, Pakistan, Australia, Brazil and the United States.
Collecting and care
Dravite is best kept as a labelled reference or collector specimen. Protect fragile crystals from impact and avoid cutting or grinding unknown material. Lead-, arsenic-, vanadium- and copper-bearing specimens are for display and careful handling only.
Dravite in popular symbolism
Some modern crystal guides associate Dravite with zodiac signs or symbolic themes based on colour, locality or collecting tradition. These associations vary between sources and are cultural interpretations, not mineralogical or medical properties.
