Peach Opal Identification Guide
Identifying peach opal by its waxy luster, low density, conchoidal fracture, and how to separate common peach opal from precious opal and imitations.
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What Peach Opal Looks Like
Peach opal is a common (potch) opal, a hydrated silica (SiO2·nH2O) with a soft, even peach to apricot body color and usually no play-of-color. It has a waxy to slightly resinous or glassy luster and ranges from translucent to opaque. The color comes from trace iron oxides. Unlike precious opal, it does not flash rainbow fire; its appeal is the smooth, uniform pastel tone, often seen in Peruvian material.
Quick visual cues
- Even peach/apricot color, sometimes with cream or pink zones
- Waxy to porcelain-like luster, no internal rainbow flashes
- Translucent edges, smooth conchoidal (shell-like) broken surfaces
- Light feel in the hand for its size
Step-by-Step Field ID Checklist
- Examine for play-of-color. Tilt under light; common peach opal shows none (if it does, it is precious opal).
- Assess luster and translucency: waxy and softly glowing rather than glassy and sharp.
- Test hardness: opal is 5.5-6.5 Mohs, softer than quartz; a steel point may scratch it.
- Check fracture: conchoidal, with no cleavage.
- Heft it: opal is light, SG ~1.9-2.2, noticeably lighter than chalcedony.
- Streak: white.
Key Diagnostic Tests
- Mohs hardness: 5.5-6.5 (softer than quartz/agate).
- Streak: white.
- Cleavage/Fracture: none/conchoidal.
- Specific gravity: ~1.9-2.2 — a key separator from denser silicas.
- Water content: opal can craze (fine cracks) if dried rapidly; hydrophane types may stick to a wet tongue.
- Acid: no reaction (rules out peach carbonates like calcite).
Common Look-Alikes and How to Tell Them Apart
- Peach chalcedony/carnelian: harder (7), denser (SG ~2.6), glassy rather than waxy; opal is lighter and softer.
- Pink/peach calcite: much softer (3), fizzes in dilute acid, and shows rhombohedral cleavage; opal does not react.
- Peach moonstone: has adularescent sheen and feldspar cleavage; opal has neither.
- Opalite (glass): uniform and may contain bubbles; true opal shows no bubbles and is slightly softer.
- Peach jasper: opaque, harder (7), and denser; jasper rings differently and resists scratching.
The best quick separators are low density (~2.0), hardness under 6.5, waxy luster, and no acid fizz.
Where Peach Opal Is Found
Peach and pink common opal is famous from Peru (the Andes), with additional sources in Mexico, Oregon and Nevada (USA), Madagascar, and Australia. It forms by low-temperature deposition of silica from groundwater in volcanic rocks, filling cavities, seams, and weathered cavities.
Frequently asked questions
How can you tell if it's real peach opal?
Real peach opal is light (SG ~2.0), waxy in luster, hardness 5.5-6.5, has conchoidal fracture, a white streak, and no acid reaction. It usually shows no rainbow play-of-color.
What does peach opal look like?
It is a soft, even apricot-to-peach stone with a waxy or porcelain glow, translucent edges, and typically no fire — its beauty is the uniform pastel color.
Peach opal vs carnelian — how do I tell them apart?
Carnelian is chalcedony: harder (7), denser, and glassy. Peach opal is softer, much lighter in weight, and has a waxier luster.
Does peach opal have fire?
Most peach opal is common opal without play-of-color. If it flashes rainbow colors as you tilt it, it qualifies as precious opal instead.