Olive Opal
A variety of Opal
What is Olive Opal?
Olive Opal is a tradename for an olive-green variety of the well-known precious stone called Opal, which is not a true mineral but a hardened silica gel. Olive Opal is mostly mined in Australia, and just like regular Opal, it is used for beads, cabochons, and tumbled stones, but it's rarely cut into faceted gems.
Optical Properties
- Refractive Index
- 1.37-1.52
- Pleochroism
- None
- Optical Character
- Isotropic
Discover Values
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Olive 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.
Olive Opal Localities Map
See where Olive Opal is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
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
- Green, greenish-yellow, brown
- Hardness (Mohs)
- 5.5 - 6
- 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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Olive Opal FAQs
How do I identify Olive Opal?
Olive Opal can be identified by its hardness of 5.5 - 6 on the Mohs scale, Green color, Vitreous, Waxy, Resinous luster, Amorphous crystal system. Look for these key characteristics when examining specimens.
What color is Olive Opal?
Olive Opal typically appears in Green, greenish-yellow, brown. Color can vary depending on impurities and formation conditions.
How hard is Olive Opal?
Olive Opal has a hardness of 5.5 - 6 on the Mohs scale. This gives it moderate hardness.
