Fire Opal
A variety of Opal
What is Fire Opal?
Fire Opal is a variety of opal that has a bright yellow, red, or orange background. It is known for its striking play of colors. It's a valuable stone, mostly because of its rarity. However, the value depends on its color and appearance. The red varieties are most expensive. This gem is often cut into faceted stones and cabochons.
Optical Properties
- Refractive Index
- 1.370-1.470
- Pleochroism
- None
- Optical Character
- Isotropic
Discover Values
This stone excels in beauty, collection value.
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Fire Opal before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Where to Find Fire Opal
RockHoundR, the free-to-download rockhounding map from the Ruby Glint team, shows where collectors find fire opal in the US, with land-access notes for BLM land and national forests. Collecting is banned in national parks.
See where to find fire opalAlways check the local rules and get the landowner's permission before you collect.
Health & Safety Information
- ⚠️Quartz, silica, crystalline silica and flint are non-toxic materials, but very fine dust containing quartz, known as respirable crystalline silicon (RCS), can cause serious and fatal lung disease. Lapidaries should exercise caution when cutting silica.
Quick Facts
Physical Properties
- Color
- Red, brown-red to brown-orange
- Hardness (Mohs)
- 5.5 - 6.5
- Rock tumbling
- With care
- Density
- 1.98 - 2.25 g/cm³
- Streak
- White
- Luster
- Vitreous, Waxy, Resinous
- Crystal System
- Amorphous
Chemical Properties
- Chemical Formula
- SiO2 · nH2O
- Elements
- H, O, Si
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Fire Opal FAQs
How do I identify Fire Opal?
Fire Opal can be identified by its hardness of 5.5 - 6.5 on the Mohs scale, Red color, Vitreous, Waxy, Resinous luster, Amorphous crystal system. Look for these key characteristics when examining specimens.
What color is Fire Opal?
Fire Opal typically appears in Red, brown-red to brown-orange. Color can vary depending on impurities and formation conditions.
How hard is Fire Opal?
Fire Opal has a hardness of 5.5 - 6.5 on the Mohs scale. This gives it moderate hardness.