RocksdayBlack Tourmaline vs Ilvaite
The quickest way to tell Black Tourmaline from Ilvaite: Black Tourmaline is clearly harder: Mohs 7–7.5 versus 5.5–6.
Schorl, the iron tourmaline and the most common species of the group. Opaque black prisms with a triangular cross-section.
Photo: Parent Géry, CC BY-SA 3.0
A black calcium-iron silicate with a dull metallic shine, first found on the island of Elba.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Quick tests
- Hardness: Black Tourmaline is clearly harder: Mohs 7–7.5 versus 5.5–6.
- Streak (rub on unglazed porcelain): Black Tourmaline leaves a white streak; Ilvaite leaves black.
Key differences
- Schorl has a white streak and a triangular cross-section.
Side by side
| Property | Black Tourmaline | Ilvaite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 7–7.5 | 5.5–6 |
| Luster | Vitreous | Submetallic |
| Streak | White | Black |
| Colors | Black | Black |
| Crystal system | Trigonal | Orthorhombic |
| Specific gravity | 3.1–3.25 | 3.8–4.1 |
| Formula | NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄ | CaFe₂FeSi₂O₇O(OH) |
| Found in | Erongo, Namibia; Minas Gerais, Brazil | Elba, Italy; Dalnegorsk, Russia |
Properties that are the same for both are grayed out.
How to identify black tourmaline
- Black prisms with lengthwise grooves.
- A broken end is a rounded triangle, not a circle.
- Hard — scratches glass. White streak, not black.
- No cleavage. A magnet does not stick.
Crystal system: Trigonal
Full Black Tourmaline guide →How to identify ilvaite
- Black stubby prisms, often striated.
- Black streak.
- Hardness about 5.5–6. Heavier than hornblende.
Crystal system: Orthorhombic
Full Ilvaite guide →More comparisons
Frequently asked questions
What is the difference between black tourmaline and ilvaite?
Black Tourmaline is a mineral with a Mohs hardness of 7–7.5 and a vitreous luster, usually black. Ilvaite is a mineral with a Mohs hardness of 5.5–6 and a submetallic luster, usually black.
How can you tell black tourmaline from ilvaite?
Black Tourmaline is clearly harder: Mohs 7–7.5 versus 5.5–6. Black Tourmaline leaves a white streak; Ilvaite leaves black. Schorl has a white streak and a triangular cross-section.
Could you tell them apart from a blurry close-up?
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