silicates
Dravite
NaMg3Al6(Si6O18)(BO3)3(OH)3(OH)
- Also known as
- brown tourmalinechrome dravite
- Crystal system
- trigonal
- Hardness
- 7–7.5 on the Mohs scale
- Lustre
- vitreous
- Colour
- Brown to yellow-brown, occasionally green
- Where it forms
- In metamorphosed sediments rich in magnesium, and in some limestones.
- Chiefly from
- Drava valley, Slovenia and AustriaAustraliaBrazilKenya
Why it is that colour
Magnesium, with iron and titanium giving the brown tones.
Safety
Safe to handle.
Where it comes from
Common, of little commercial interest except for the rare chromium-rich green material.
Historical use
Named in 1884 after the Drava river district. Of geological rather than gemmological interest — dravite in a metamorphic rock indicates the sediment it formed from was rich in boron and magnesium, which constrains what it originally was.
Recorded as history and attributed where possible. That a stone was used for something establishes that people used it, not that it worked.
Worth knowing
Dravite completes the trio that makes the group's point. Schorl is the iron tourmaline, elbaite the lithium one, dravite the magnesium one. Same structure, same boron backbone, different metal in one position, and the results range from a black waste mineral to the most expensive coloured gem in the world.
Tourmaline is arguably the best single illustration in mineralogy of how little it takes to change what something is worth, and how little that has to do with what it is.
Identity checked against IMA-CNMNC master list, June 2025.