RocksdayOlivine vs Prasiolite
The quickest way to tell Olivine from Prasiolite: Olivine feels noticeably heavier for its size (specific gravity 3.2–4.4 vs 2.65).
Olive-green silicate that makes up most of Earth's upper mantle. Gem-quality olivine is called peridot.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Green quartz. Natural pieces are uncommon; nearly all prasiolite for sale is amethyst that has been heated, or yellow quartz that has been irradiated.
Photo: Mauro Cateb, CC BY-SA 4.0
Quick tests
- Heft: Olivine feels noticeably heavier for its size (specific gravity 3.2–4.4 vs 2.65).
Key differences
- Peridot is heavier, grainier and a brighter bottle green.
Side by side
| Property | Olivine | Prasiolite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 6.5–7 | 7 |
| Luster | Vitreous | Vitreous |
| Streak | White | White |
| Colors | Green, Yellow | Green |
| Crystal system | Orthorhombic | Trigonal |
| Specific gravity | 3.2–4.4 | 2.65 |
| Formula | (Mg,Fe)₂SiO₄ | SiO₂ |
| Found in | Papakōlea, Hawaii; San Carlos, Arizona | Lower Silesia, Poland; Bahia, Brazil |
Properties that are the same for both are grayed out.
How to identify olivine
- Bottle- to olive-green glassy grains.
- Often as sugary green clumps in black basalt.
- No cleavage — breaks like glass.
- Hard enough to scratch glass.
Crystal system: Orthorhombic
Full Olivine guide →How to identify prasiolite
- Even leek-green to olive, not banded like aventurine.
- Hardness 7, with quartz's curved fracture.
- Heated amethyst often keeps a geode shape with paler bases.
Crystal system: Trigonal
Full Prasiolite guide →More comparisons
Frequently asked questions
What is the difference between olivine and prasiolite?
Olivine is a mineral with a Mohs hardness of 6.5–7 and a vitreous luster, usually green or yellow. Prasiolite is a mineral (SiO₂) with a Mohs hardness of 7 and a vitreous luster, usually green.
How can you tell olivine from prasiolite?
Olivine feels noticeably heavier for its size (specific gravity 3.2–4.4 vs 2.65). Peridot is heavier, grainier and a brighter bottle green.
Could you tell them apart from a blurry close-up?
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