Synthetic Opal
Synthetic Opal is lab-grown gem (silica or silica-resin). In the hand, it rates 4.5 to 6 on the Mohs scale, and it runs white with rainbow flash and black with rainbow flash. Affordable; a fraction of natural precious opal prices.
The geology.
Synthetic Opal carries the formula SiO2·nH2O (lab-assembled spheres, often resin-impregnated). It belongs to the amorphous (none) system. On paper it is lab-grown gem (silica or silica-resin).
It sits at 4.5 to 6 on the Mohs scale. The surface reads vitreous to resinous. Light behaviour is translucent to opaque. Specific gravity runs 1.8 to 2.1. The streak is white. It breaks with conchoidal fracture.
Play-of-color arranged in a regular mosaic, under a loupe the patches show a 'lizard skin' or 'chicken wire' cell structure, and viewed from the side the color runs in parallel columns.
Expect to see it as cabochons, beads, carvings, inlay in jewelry or rough blocks.
The origins.
Factory product, pioneered by Gilson in 1974, now produced mainly by Kyocera and Chinese labs.
On value, the database notes: affordable; a fraction of natural precious opal prices.
Traditional associations.
In energy work traditions, lab opal is considered an aesthetic stand-in that carries the maker's intent rather than geological memory.
Recorded here because it is part of how this material is sold, not because it is a property of the material.
Spotting the real thing.
Play-of-color arranged in a regular mosaic, under a loupe the patches show a 'lizard skin' or 'chicken wire' cell structure, and viewed from the side the color runs in parallel columns.
This IS the simulant: routinely sold as Australian or Ethiopian opal, especially in inlay jewelry and bead strands; 'monarch' and 'aurora' opal with too-perfect webbing are lab products.
| Looks like | How to tell them apart |
|---|---|
| Precious opal (natural) | Natural play-of-color is irregular and patchy; synthetic shows orderly snakeskin cells and columnar color from the side |
| Opalite | Opalite is plain milky glass with zero play-of-color, just a blue-orange glow |
| Ethiopian opal | Ethiopian opal is hydrophane (sticks to tongue, soaks up water); most synthetics do not |
At-home tests.
None of these need a lab. A 10x loupe, good daylight and a steady hand cover most of what a buyer needs to know about synthetic opal.
| Test | What you should see |
|---|---|
| Loupe | lizard-skin/honeycomb cell boundaries inside each color patch |
| Side view | color in vertical columns instead of random patches |
| By eye | Polymer-impregnated types feel light (SG below ~2.0) and may smell of plastic on a hot needle |
Destructive tests belong to a gemologist, not a kitchen table. If a piece matters to you, pay for an appraisal before you take a file to it.
Care & handling.
At 4.5 to 6 on the Mohs scale this is a soft material. Keep it as a display piece, store it apart from harder stones, and skip daily-wear settings.
It breaks with conchoidal fracture, which is worth knowing before you set it or drop it.
Clean it by hand, dry it properly, and keep it away from ultrasonic cleaners and hot steam.
A deeper look.
Extended detail on composition, sourcing, authentication and market value.
The physical record
The formula on record is SiO2·nH2O (lab-assembled spheres, often resin-impregnated). Crystal system: Amorphous (none). Specific gravity: 1.8 to 2.1. Streak: White. Cleavage and fracture: Conchoidal fracture.
How it reaches the market
Factory product, pioneered by Gilson in 1974, now produced mainly by Kyocera and Chinese labs.
What it gets confused with
Precious opal (natural): Natural play-of-color is irregular and patchy; synthetic shows orderly snakeskin cells and columnar color from the side. Opalite: Opalite is plain milky glass with zero play-of-color, just a blue-orange glow. Ethiopian opal: Ethiopian opal is hydrophane (sticks to tongue, soaks up water); most synthetics do not.
What it is worth
Affordable; a fraction of natural precious opal prices.
Where buyers get caught
This IS the simulant: routinely sold as Australian or Ethiopian opal, especially in inlay jewelry and bead strands; 'monarch' and 'aurora' opal with too-perfect webbing are lab products.
One more thing
Gilson 'opal' was so convincing it forced gem labs to develop the snakeskin test within months of its 1974 debut, the giveaway is that it is too orderly, a problem nature never has.
An education-first guide.
We do not stock synthetic opal. Writing it up regardless is the point of a reference library.
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