mineral
Fire Opal
Hydrated Silica (SiO2·nH2O)
Hardness: 5.5-6.5 on Mohs scale; Color: Red, orange, or yellow; Luster: Vitreous to resinous; Crystal structure: Amorphous; SG: 1.9-2.3.
- Hardness
- 5
- Color
- Red, orange, or yellow
- Luster
- Vitreous to resinous
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Physical properties
Hardness: 5.5-6.5 on Mohs scale; Color: Red, orange, or yellow; Luster: Vitreous to resinous; Crystal structure: Amorphous; SG: 1.9-2.3.
Formation & geological history
Formed by the cooling of silica-rich water in volcanic rock cavities (often rhyolite) during the Tertiary period. This specimen appears to be a cabochon-cut gemstone.
Uses & applications
Primarily used in high-end jewelry as a gemstone and highly valued by mineral collectors for its vivid colors.
Geological facts
Unlike many opals, fire opals (especially from Mexico) can be transparent to translucent and may or may not show play-of-color. Some are called 'Cherry Opals'.
Field identification & locations
Identified by its distinctive orange-red hue and jelly-like transparency. Often found in volcanic regions of Mexico, Ethiopia, and Australia.
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Mineral/Rock
Banded Gneiss (River Rock/Pebble)
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Metamorphic Rock
![Biotite Schist (Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]) — metamorphic](https://media.rock.id/9ca564b5-bc87-402b-965a-69b21f9aa6bf-thumbnail.jpg)
Biotite Schist
Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]
metamorphic