Vanadium Tourmaline Identification Guide
Identify vanadium tourmaline, a vivid chrome-like green tourmaline colored by vanadium, and tell it from chrome tourmaline, emerald, and tsavorite.
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What Vanadium Tourmaline Looks Like
Vanadium tourmaline is a vanadium-bearing green tourmaline (usually a dravite/uvite-elbaite group stone) whose intense bluish-to-emerald green color is caused by vanadium (and sometimes chromium). It looks like a rich, saturated "chrome green" gem, transparent and bright, typically faceted from East African rough. Crystals show the classic tourmaline prismatic habit with a rounded triangular cross-section and lengthwise striations; luster is vitreous. The color can appear more vivid under certain lighting, and the best material rivals fine emerald.
Step-by-Step Field-ID Checklist
- Confirm tourmaline form. Prismatic crystal, rounded triangular cross-section, striations along the length.
- Assess color. Vivid, saturated green (emerald-to-chrome green).
- Check pleochroism. Tourmaline is strongly pleochroic - the green darkens viewed down the crystal length.
- Hardness test. Scratches glass; not scratched by steel.
- Look for no cleavage and conchoidal fracture.
- Weigh it. Density ~3.0-3.1, lower than garnet of the same size.
Key Diagnostic Tests
- Mohs hardness: ~7-7.5.
- Streak: White.
- Cleavage/fracture: Poor/no cleavage; conchoidal to uneven fracture.
- Magnetism: None.
- Acid: No reaction.
- Density: ~3.0-3.1 g/cm3.
- Pleochroism: Strong - a key tourmaline confirmation that separates it from singly refractive garnet.
- Color filter / spectroscopy: Lab tools distinguish vanadium vs chromium coloring; the trade often markets either as "chrome tourmaline."
Common Look-Alikes
- Chrome tourmaline: Essentially the same green tourmaline but colored mainly by chromium; visually identical, separated only by chemistry. Both are sold as vivid green tourmaline.
- Tsavorite (green grossular garnet): Isometric, singly refractive, NO pleochroism, higher density (~3.6) - the pleochroism and density separate them quickly.
- Emerald (beryl): Hexagonal, lower density (~2.7), different inclusions, weaker single-direction dichroism.
- Chrome diopside: Has two cleavages and lower hardness (~5.5-6).
- Green elbaite (verdelite): Lithium-colored green tourmaline; chemistry differs but field properties overlap.
Strong pleochroism, hardness ~7.5, no cleavage, and density ~3.0-3.1 identify it as tourmaline; the vanadium vs chrome distinction needs lab analysis.
Where It Is Found
Vanadium-rich green tourmalines come chiefly from East Africa - Tanzania (Umba, Landanai) and Kenya, with related material from Madagascar and Brazil. They occur in metamorphic and metasomatic settings where vanadium/chromium are available.
Frequently asked questions
What is vanadium tourmaline?
It is a vivid green tourmaline whose saturated color is caused mainly by vanadium (sometimes with chromium), often marketed alongside chrome tourmaline.
How do you tell vanadium tourmaline from tsavorite garnet?
Vanadium tourmaline is strongly pleochroic, has lower density (~3.0-3.1), and has tourmaline crystal form, while tsavorite garnet is singly refractive with no pleochroism and higher density (~3.6).
Is vanadium tourmaline the same as chrome tourmaline?
They look the same and are both vivid green tourmaline; the difference is the coloring element (vanadium vs chromium), which can only be confirmed by chemical or spectroscopic analysis.
How can you tell vanadium tourmaline from emerald?
Tourmaline has a rounded triangular cross-section, strong pleochroism, and hardness ~7.5, while emerald is hexagonal, lower density, and shows different inclusions.