RocksdayOlivine vs Scorodite
The quickest way to tell Olivine from Scorodite: Olivine scratches glass (Mohs 6.5–7); Scorodite can't (Mohs 3.5–4).
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
A hydrated iron arsenate that forms pale green or blue crystals where arsenic ores weather.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Quick tests
- Scratch glass: Olivine scratches glass (Mohs 6.5–7); Scorodite can't (Mohs 3.5–4).
Key differences
- Olivine is much harder and does not form on weathered ore.
Side by side
| Property | Olivine | Scorodite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 6.5–7 | 3.5–4 |
| Luster | Vitreous | Vitreous to earthy |
| Streak | White | White |
| Colors | Green, Yellow | Green, Blue, Gray, Brown |
| Crystal system | Orthorhombic | Orthorhombic |
| Specific gravity | 3.2–4.4 | 3.1–3.3 |
| Formula | (Mg,Fe)₂SiO₄ | FeAsO₄·2H₂O |
| Found in | Papakōlea, Hawaii; San Carlos, Arizona | Tsumeb, Namibia; Ojuela mine, Mapimí, Mexico |
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 scorodite
- Pale green, blue-green or gray pyramidal crystals or crusts.
- Hardness about 3.5–4.
- On or near arsenopyrite or other arsenic minerals.
Crystal system: Orthorhombic
Full Scorodite guide →More comparisons
Frequently asked questions
What is the difference between olivine and scorodite?
Olivine is a mineral with a Mohs hardness of 6.5–7 and a vitreous luster, usually green or yellow. Scorodite is a mineral (FeAsO₄·2H₂O) with a Mohs hardness of 3.5–4 and a vitreous to earthy luster, usually green, blue, gray or brown.
How can you tell olivine from scorodite?
Olivine scratches glass (Mohs 6.5–7); Scorodite can't (Mohs 3.5–4). Olivine is much harder and does not form on weathered ore.
Could you tell them apart from a blurry close-up?
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