RocksdayEmerald vs Tourmaline
How to tell them apart
Green beryl colored by chromium or vanadium — one of the four classic precious gems.
Photo: Géry PARENT, CC0
A boron-bearing silicate found in more colors than almost any other gem. Black schorl is the most common form.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Key differences
- Green tourmaline has a triangular cross-section and striations.
Side by side
| Property | Emerald | Tourmaline |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 7.5–8 | 7–7.5 |
| Luster | Vitreous | Vitreous |
| Streak | White | White |
| Colors | Green | Black, Green, Pink |
| Crystal system | Hexagonal | Trigonal |
| Specific gravity | 2.67–2.78 | 3–3.3 |
| Formula | Be₃Al₂Si₆O₁₈ (with Cr/V) | Complex borosilicate |
| Found in | Muzo and Chivor, Colombia; Kafubu, Zambia | Mount Mica, Maine; San Diego County, California |
Properties that are the same for both are grayed out.
How to identify emerald
- Deep green six-sided prisms with flat ends.
- Almost always has internal fractures and inclusions.
- Hardness 7.5–8.
Crystal system: Hexagonal
Full Emerald guide →How to identify tourmaline
- Long prisms with lengthwise grooves (striations).
- Rounded-triangle cross-section when broken across.
- Hard — scratches glass.
- Gem crystals can change color from end to end ('watermelon').
Crystal system: Trigonal
Full Tourmaline guide →More comparisons
Could you tell them apart from a blurry close-up?
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