Fire Opal

Fire opal gets its name from the beautiful, rich orange body color. Good-quality stones are transparent, not milky. It is common to use a fire opal in rings. It may also be cut en cabochon in case of its milkiness. The rough crystal of the stone occurs in the rhyolite host rock.

Occurrence

Opal fills cavities in sedimentary rocks or veins in igneous rocks. It forms stalagmites or stalactites and replaces organic material in fossil wood, shell, and bone. The main producers of fire opal are Sudan and Mexico.

Fire Opal Properties

• Specific Gravity: 2.10
• Refractive Index: 1.37-1.47
• Birefringence (DR): None
• Luster: Vitreous
• Crystal Structure: Amorphous
• Composition: Hydrated silica gel
• Hardness: 6

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Crystals Directory

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F

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I

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M

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Birthstone

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