Dravite Identification Guide
A field guide to identifying dravite, the sodium-magnesium brown tourmaline, by its color, striated prisms, and how it differs from schorl and other tourmalines.
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What It Looks Like
Dravite is the sodium-magnesium-rich member of the tourmaline group. Its classic color is rich brown — from honey and cinnamon to dark coffee and near-black — sometimes yellowish or greenish brown. Luster is vitreous; transparency runs from transparent (gem dravite) to translucent and opaque. Crystals form elongate prisms with rounded-triangular cross sections and strongly striated faces running parallel to the c-axis. Terminations are often hemimorphic (different at each end).
Telltale Visual Cues
- Warm brown body color, frequently with strong pleochroism (lighter to darker brown when rotated).
- Three-sided, rounded prismatic habit with deep vertical striations.
- No cleavage; surfaces look glassy where freshly broken.
Step-by-Step Field-ID Checklist
- Examine the cross section: a rounded triangular (trigonal) outline strongly suggests tourmaline.
- Look for striations: parallel grooves down the prism length are diagnostic of tourmaline group.
- Judge the color: brown to brownish-yellow points toward dravite (versus jet-black schorl).
- Check hardness: dravite is Mohs 7–7.5; it scratches quartz.
- Look for absent cleavage: tourmaline shows none — it breaks unevenly to conchoidally.
- Test pleochroism: rotate a translucent fragment in light; tourmaline commonly shows two distinct brown tones.
Key Diagnostic Tests
- Mohs hardness: 7–7.5.
- Streak: white to pale brown.
- Cleavage: none (very poor); fracture uneven to conchoidal.
- Density: ~3.0–3.1 g/cm³.
- Magnetism: nonmagnetic.
- Pyroelectric/piezoelectric: like all tourmaline, can attract dust or ash when warmed — a classic tourmaline confirmation.
Common Look-Alikes
- Schorl (iron tourmaline): black and opaque; dravite is brown and often translucent. Schorl prisms are usually larger and jet-black.
- Andalusite: brown but shows distinct cleavage and a more squarish cross section.
- Smoky quartz: brown but hexagonal with horizontal striations and no triangular cross section; hardness 7.
- Axinite: brown but bladed, with one good cleavage, unlike tourmaline's rounded triangular prism.
- Dark zircon: much denser (~4.7) and tetragonal.
Where It Is Found
Dravite was first described from Dravograd (the Drava River area), Slovenia/Austria. Gem and crystal dravite comes from Australia (notably the famous brown crystals), Brazil, Tanzania (chrome-bearing green dravite), Kenya, Sri Lanka, and the USA. It typically occurs in metamorphosed limestones and dolomites, schists, and contact-metamorphic zones rich in magnesium.
Frequently asked questions
What color is dravite tourmaline?
Dravite is typically brown — honey, cinnamon, coffee, or dark brown — and can be yellowish or greenish brown. Chrome-bearing dravite from Tanzania can be a vivid green.
What is the difference between dravite and schorl?
Both are tourmalines, but dravite is sodium-magnesium and usually brown and often translucent, while schorl is sodium-iron and jet-black and opaque. Color is the quickest field distinction.
How can you tell if a brown crystal is dravite?
Look for a rounded triangular cross section, vertical striations down the prism, hardness around 7–7.5, no cleavage, and brown pleochroism. Tourmaline also attracts dust when warmed.
Is dravite a gemstone?
Yes. Transparent brown dravite is faceted as a gem, and the chrome-rich green variety is prized. Most dravite, however, occurs as opaque to translucent crystals collected for mineral specimens.