mineral
Opal
Hydrated amorphous silica (SiO2·nH2O)
AI-generated identification · may be incorrectHardness: 5.5-6.5 on Mohs scale. Color: Variable, showing a play-of-color. Luster: Subvitreous to pearly. Crystal structure: Amorphous, lacking a true crystalline lattice.
- Hardness
- 5
- Color
- Variable, showing a play-of-color
- Luster
- Subvitreous to pearly
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Physical properties
Hardness: 5.5-6.5 on Mohs scale. Color: Variable, showing a play-of-color. Luster: Subvitreous to pearly. Crystal structure: Amorphous, lacking a true crystalline lattice.
Formation & geological history
Formed from a solution of silica and water, typically deposited in fissures within various sedimentary or volcanic rocks.
Uses & applications
Primarily used as a precious gemstone in jewelry, rings, necklaces, and collector displays.
Geological facts
Opal contains up to 21% water by weight and exhibits a unique play-of-color caused by the diffraction of light through microscopic silica spheres.
Field identification & locations
Identify by its characteristic play-of-color and amorphous structure. Commonly sourced from Australia, Ethiopia, and Mexico.
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