RocksdayLabradorite vs Opal
How to tell them apart
A gray plagioclase feldspar that flashes electric blue, green and gold when light hits it at the right angle.
Photo: Parent Géry, Public domain
Hydrated silica with no crystal structure. In precious opal, stacked microscopic spheres split light into flashing rainbow patches.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Key differences
- Opal's color appears as pinpoint patches from many angles; labradorite flashes as a sheet.
- Labradorite flashes as one sheet of color from one angle.
Side by side
| Property | Labradorite | Opal |
|---|---|---|
| Type | Mineral | Mineraloid |
| Mohs hardness | 6–6.5 | 5.5–6.5 |
| Luster | Vitreous | Vitreous to waxy |
| Streak | White | White |
| Colors | Gray, Black, Blue | White, Black, Orange |
| Crystal system / structure | Triclinic | Amorphous |
| Specific gravity | 2.68–2.72 | 1.9–2.3 |
| Formula | (Ca,Na)(Al,Si)₄O₈ | SiO₂·nH₂O |
| Found in | Labrador, Canada; Finland | Coober Pedy, Australia; Lightning Ridge, Australia |
Properties that are the same for both are grayed out.
How to identify labradorite
- Dull gray until tilted — then a vivid blue/green flash.
- Fine parallel lines on cleavage faces.
- Hardness about 6.
- Flash only appears from one direction.
Crystal system: Triclinic
Full Labradorite guide →How to identify opal
- Flashes of spectral color that shift as you turn it.
- Waxy to glassy luster.
- Light in weight for a gemstone.
- Common opal lacks color play and looks milky.
Structure: Amorphous
Full Opal guide →More comparisons
Could you tell them apart from a blurry close-up?
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