Fake Crystals: How to Spot Them (4 Tests)
Spot fake crystals with 4 simple tests: scratch, backlight, loupe, and acetone. Real vs. dyed howlite, opalite, heat-treated citrine, and more.
Updated 27 August 2026
To spot a fake crystal, use four tests. Scratch it, because real quartz is Mohs 7 and scratches glass, while most fakes and dyed stones are soft. Backlight it, because glass shows an even orange glow and dye pools in the cracks. Look at it under a 10x loupe, because round bubbles mean glass. Swab a hidden spot with acetone, because dye lifts and natural colour stays. No single test is proof, but together they expose most of what the trade passes off. The stone doing the least to hide itself is usually the honest one.
Fakes fall into three groups. Manufactured glass (opalite, goldstone, cherry quartz). Dyed or treated stone sold as something rarer (howlite as turquoise, heated amethyst as citrine). And substitutions (labradorite as moonstone). Here is how to tell each one, plus a reference table of the roughly 36 most-faked stones.
What are the fastest ways to tell if a crystal is real?
Five tests catch most fakes with tools you already own.
- Hardness, the glass scratch. Real quartz (amethyst, citrine, rose, smoky) is Mohs 7 and scratches glass, and a steel knife will not scratch it. Most soft fakes go the other way. Dyed howlite (3.5) and calcite (3) are cut easily by a knife.
- Backlight test. Opalite and other glass glow warm orange when you light them from behind. Dyed stones show colour gathered in cracks and drill holes rather than spread evenly through the body.
- 10x loupe. Round gas bubbles and swirl marks mean molten glass. Real crystals show growth zoning, inclusions or mineral grain, never round bubbles.
- Acetone swab. Rub a hidden area with a cotton bud dampened in acetone. Dye lifts onto the swab. Natural colour does not.
- Streak test. Rub the stone on unglazed tile. Malachite streaks green, hematite red, lapis blue, jet brown. A fake made of a different material streaks the wrong colour, or does not streak at all.
Is my citrine real or heat-treated amethyst?
Most "citrine" sold is heat-treated amethyst, and the tell is conclusive. Amethyst roasted at roughly 400 to 550 °C turns orange-brown, which leaves a chalky white base and a sharp break into deep orange at the tips. Natural citrine is paler, and its colour either fades gently or carries on evenly through the base of the crystal. Both stones are quartz at Mohs 7, so hardness will not separate them. Only the way the colour sits will. Heat treatment is permanent, and apart from that colour boundary no consumer test can detect it. Natural citrine's soft yellow can also weaken under long UV exposure. The roasted orange does not.
Is my turquoise real or dyed howlite?
The great majority of commercial turquoise is treated, and a large share of cheap "turquoise" is dyed howlite or magnesite, not turquoise at all. Turquoise is Mohs 5 to 6 and resists a steel knife. Dyed howlite and magnesite are 3.5 and cut like chalk, with colour pooled in the veins and a white core showing under any scratch. Two confirmations. Acetone on a cotton bud lifts blue dye off howlite and leaves turquoise unchanged. A drill hole in a dyed stone shows a white interior. To separate howlite from magnesite, use acid. Magnesite is a carbonate and fizzes. Howlite does not react.
Is my moonstone real or opalite?
Opalite is manufactured glass with no natural counterpart, despite being sold as "moonstone", "opal" and "sea opal". Real moonstone is a feldspar (Mohs 6 to 6.5) with a soft, blue-white sheen that moves as you tilt it, and it has cleavage steps at roughly 90°, meaning it breaks in flat steps close to a right angle. Opalite betrays itself under a backlight. It glows warm orange lit from behind, glows cold blue in reflection, and shows round bubbles under a loupe. A related trap is "rainbow moonstone", which is really white labradorite. That is a real stone and honestly beautiful, but it is not moonstone. Its blue flash comes in separate patches with black needle inclusions. True moonstone's sheen is continuous and billowy across the whole stone.
Is aura quartz natural or coated?
Aura quartz is real quartz with a manufactured metal coating a few atoms thick, bonded on in a vacuum chamber using vaporised titanium, gold or niobium. The process has been commercial since the 1980s. The stone is genuine. The rainbow colour is not natural. Find any chipped, sawn or broken area. A coated stone shows ordinary colourless quartz underneath. True iridescence from inside the stone (labradorite, rainbow obsidian) sits within the body and moves as you tilt through one plane, rather than coating every surface the same way. Aura quartz is honest when it is disclosed. The fault lies only with sellers who imply the colour is natural.
Reference table: the most-faked stones and how to catch them
These stones are routinely dyed, heated, coated, reconstituted or manufactured outright. "Treated" is not automatically fraud, and most treatments are legitimate when they are disclosed, but you deserve to know.
| Stone | What's done to it | The catch |
|---|---|---|
| Citrine | Heat-treated amethyst | White base, sharp orange tips |
| Turquoise | Dyed howlite or magnesite, stabilised, "block" resin | Soft fakes cut like chalk. Acetone lifts dye |
| Howlite | The most-dyed stone in the trade | Scratches like chalk (3.5). White under the dye |
| Magnesite | Dyed as turquoise, "lemon chrysoprase" | Fizzes in acid. Howlite does not |
| Opalite | Entirely manufactured glass | Orange backlight glow. Round bubbles |
| Goldstone / Blue Goldstone | Manufactured glass plus copper or cobalt | Even sparkle everywhere. Bubbles. No cleavage |
| Cherry Quartz | Manufactured glass | No natural equivalent exists. Bubbles and swirl |
| Strawberry Quartz | Almost always glass | Uniform flake size. Bubbles |
| Aura Quartz | Vacuum metal coating on real quartz | Colourless quartz under any chip |
| Smoky Quartz | Often irradiated colourless quartz | Unnaturally uniform, no pale base zone |
| Prasiolite | Heated amethyst | The pale even mint colour is the tell |
| Carnelian | Iron-stained, heat-treated agate | Hard-edged dye stripes. Glows when backlit |
| Black Onyx | Grey agate carbonised with sugar and acid | Scratches glass. Jet is softer and streaks brown |
| Lapis Lazuli | Dyed, waxed, "lapis" jasper, Gilson synthetic | Dye lifts on acetone. No pyrite is suspect |
| Malachite | Wax or resin stabilised, reconstituted powder | Banding too regular. Plastic feel |
| Serpentine | Dyed as "new jade", "olive jade", "Korean jade" | Softer than jade. A steel knife scratches it |
| Jadeite Jade | Type B acid-and-polymer, Type C dyed | Etched crack-net under polymer. Dye in fissures |
| Tiger's Eye | Heat, acid and dye (red, honey, blue variants) | Dyed colours read unnaturally saturated |
| Amber | Pressed (ambroid), dyed, clarified | Plastic sinks in salt water. No UV glow |
| Kunzite | Irradiated to deepen the pink | Fades faster than natural. Lab-only detection |
| Aquamarine / Morganite / Tanzanite | Near-universal heat treatment | Permanent and undetectable. Assume treated |
| Emerald | Oil or resin fracture-filling, synthetics | Look for a "jardin". Bubbles mean glass |
FAQ
Does a fake crystal always have bubbles?
Round bubbles are conclusive proof of glass, because real crystals never have them. But their absence does not prove a stone is real. Dyed and reconstituted stones are real mineral matter with no bubbles in them. Use bubbles to catch glass, then use hardness, acetone and streak for the rest.
Is dyed or treated stone the same as fake?
Not always. Most treatments, such as oiling emerald, heating aquamarine and waxing jade, are standard, disclosed and legitimate. It becomes fraud when it is not disclosed, or when one material (howlite) is sold as another (turquoise). The honest test is whether the seller tells you.
Can I test a crystal without damaging it?
Yes. Backlighting, the 10x loupe, a streak on tile and an acetone swab on a hidden spot are all non-destructive. Save scratch tests for an inconspicuous edge or a drill hole, and never acid-test a stone anywhere but a hidden spot that is already damaged.
The incumbent crystal sites will not tell you your stone is fake, because they are the ones selling it. Oraclite identifies any stone from a photo, flags the fakes, and names the treatment, free to try.