RocksdayEpidote vs Vesuvianite
How to tell them apart
A pistachio-green metamorphic mineral. Mixed with pink feldspar it forms the popular stone 'unakite'.
Photo: Gleb Korovko, CC BY 4.0
A silicate of contact-metamorphosed limestones, forming square prisms in greens and browns.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Quick tests
- Streak (rub on unglazed porcelain): Epidote leaves a gray to white streak; Vesuvianite leaves white.
Key differences
- Epidote is darker and its crystals aren't square in section.
Side by side
| Property | Epidote | Vesuvianite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 6–7 | 6–7 |
| Luster | Vitreous | Vitreous to resinous |
| Streak | Gray to white | White |
| Colors | Green, Black | Green, Brown, Yellow, Purple |
| Crystal system | Monoclinic | Tetragonal |
| Specific gravity | 3.3–3.6 | 3.32–3.43 |
| Formula | Ca₂(Al₂Fe)(SiO₄)(Si₂O₇)O(OH) | Ca₁₀(Mg,Fe)₂Al₄(SiO₄)₅(Si₂O₇)₂(OH,F)₄ |
| Found in | Prince of Wales Island, Alaska; Knappenwand, Austria | Mount Vesuvius, Italy; Jeffrey mine, Quebec |
Properties that are the same for both are grayed out.
How to identify epidote
- Distinctive pistachio to dark green.
- Striated prisms.
- Hardness 6–7.
- Commonly fills cracks in altered rocks.
Crystal system: Monoclinic
Full Epidote guide →How to identify vesuvianite
- Square-sectioned prisms with striations.
- Olive green to brown, glassy.
- Hardness about 6.5.
Crystal system: Tetragonal
Full Vesuvianite guide →More comparisons
Could you tell them apart from a blurry close-up?
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