fire opal

mineral

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Last updated

June 26, 2026

Quick Summary

Fire opal is a variety of opal, a silica mineral known for its use as a gemstone. While opal is fundamentally colorless, impurities often give it body colors ranging from yellow and red (from iron oxides) to black (from manganese oxides and organic carbon). Fire opals are characterized by a yellow, orange, or red body color and are more common than black opal.1

Precious opals, including fire opals, display a play of colors that flash and change as the stone is viewed from different angles. This effect is caused by the interference of light within the mineral's internal structure. Fire opals are typically facet cut, while other precious opals are usually finished en cabochon to best display their optical properties.1

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opal
Fire opals usually are facet cut, but most other precious opals are finished en cabochon because their optical properties are best displayed on smoothly rounded surfaces. Undersized fragments are used for inlay work, and small pieces scattered throughout a natural matrix are commonly sold under…
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Fire opals usually are facet cut, but most other precious opals are finished en cabochon because their optical properties are best displayed on smoothly rounded surfaces. Undersized fragments are used for inlay work, and small pieces scattered throughout a natural matrix are commonly sold under…
Read More