Vanadium Tourmaline
Vanadium-bearing tourmaline, e.g. NaMg3V6(Si6O18)(BO3)3(OH)3O (vanadium dravite)
Vanadium-colored tourmaline, including the species vanadium dravite, producing rich emerald-green hues similar to chrome tourmaline.
- Mohs hardness
- 7-7.5
- Color
- Rich green to blue-green
- Type
- mineral
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Overview
Vanadium tourmaline refers to tourmaline colored or dominated by vanadium, including the recognized species vanadium dravite (vanadiumdravite), in which vanadium occupies octahedral sites. Vanadium produces a rich green to blue-green color closely resembling that of chromium-colored tourmaline.
In the gem trade, vanadium- and chromium-bearing green tourmalines are often grouped together as "chrome tourmaline" because both elements yield similarly vivid greens. As a defined species, vanadium dravite is rare.
These tourmalines are notable for connecting tourmaline coloration to the same vanadium chemistry that colors tsavorite garnet and some emeralds.
Formation & geology
Vanadium tourmalines form in metamorphic and metasomatic rocks enriched in vanadium and boron, frequently linked to graphitic and ultramafic-derived host rocks, the same environments that produce vanadium-rich tsavorite and chrome tourmaline.
East African deposits, particularly in Tanzania and Kenya, are important sources of vanadium- and chromium-colored green tourmaline. Vanadium dravite as a species has been characterized from specific metamorphic localities.
The presence of mobile vanadium during boron-rich metamorphism, combined with magnesium-rich conditions favoring dravite, drives crystallization toward vanadium-bearing tourmaline.
How to identify it
Vanadium tourmaline shows saturated green to blue-green color, vitreous luster, hardness 7-7.5, strong pleochroism, striated prismatic habit, triangular cross-section, and no cleavage.
Vanadium versus chromium coloration cannot be separated by eye; spectroscopy or chemical analysis is needed, and the two are commercially lumped as chrome tourmaline. Color filters and absorption spectra help gemologists distinguish vanadium/chrome greens from iron-colored greens.
Look-alikes include tsavorite garnet (no pleochroism, isotropic), emerald, and chrome diopside; tourmaline's strong pleochroism and birefringence are diagnostic.
Uses & significance
Transparent vanadium-bearing green tourmaline is cut as desirable gemstones marketed alongside chrome tourmaline, valued for an intense, emerald-like green that holds color well in artificial light.
As minerals, vanadium dravite and vanadian tourmalines are collected and studied for trace-element coloration mechanisms. Green tourmalines generally carry heart-chakra and vitality associations in metaphysical practice, though this is not a scientific property.
Frequently asked questions
What is vanadium dravite?
It is a tourmaline species in which vanadium dominates the octahedral sites of a dravite-type structure, producing vivid green color.
Why is vanadium tourmaline sold as chrome tourmaline?
Vanadium and chromium both create very similar rich greens, so the trade groups them together as chrome tourmaline.
Where does vanadium tourmaline come from?
Important sources are East African deposits in Tanzania and Kenya, tied to vanadium-rich metamorphic rocks.
How can you tell vanadium from chromium coloring?
Only spectroscopic or chemical analysis can distinguish them; they look identical to the eye.
Vanadium Tourmaline guides
In-depth guides for identifying, valuing, and understanding Vanadium Tourmaline.
