How to Tell if Crystals Are Real
Many crystals sold in shops and online aren't quite what the label says. Opalite and goldstone are glass, most citrine is heated amethyst, cheap “turquoise” is often dyed howlite, and aura quartz is coated. Here are the 20 fakes and treatments you'll meet most often, and the simple checks that catch them.
Natural
Formed by nature and not altered beyond cutting and polishing.
Treated
A natural stone whose color or durability was changed by heating, irradiation, dyeing, coating or filling.
Lab-grown
The same material with the same chemistry, grown in a lab. Not fake, but it must be labeled.
Imitation
Something else that only looks like the stone, such as glass, plastic or dyed howlite.
Identify Your Crystal First
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A photo shows what a stone looks like, but it can't reliably detect dye, heating, irradiation or thin coatings. Pair the result with the checks below.
20 Common Fake, Dyed and Treated Crystals
What each is sold as, what it really is, and how to tell.
| Sold as | What it really is | How to tell | The risk |
|---|---|---|---|
| Opalite, 'sea opal' | Really: Man-made opalescent glass | How to tell: Bluish against dark backgrounds and milky orange-pink against light ones, often with tiny bubbles. Cheap, even color, no play-of-color. | The risk: Fine as glass; misleading if sold as opal or moonstone |
| Goldstone | Really: Man-made glass with copper crystals (blue uses cobalt) | How to tell: Perfectly even glitter from every angle; bubbles in cheaper pieces. | The risk: Fine as glass; misleading if sold as sunstone or aventurine |
| Cherry quartz, blue quartz, strawberry quartz beads | Really: Usually glass (imitation strawberry quartz is glass with red particles) | How to tell: Wispy color swirls, round gas bubbles, vivid even color and a low price. Natural strawberry quartz has visible mineral inclusions. | The risk: Paying quartz prices for glass |
| Cheap bright turquoise | Really: Dyed howlite or magnesite | How to tell: Softer than turquoise; white shows inside chips and drill holes; dye collects in cracks. Undyed howlite is sold as 'white turquoise', which doesn't exist. | The risk: Deceptive if sold as turquoise |
| Turquoise | Really: Stabilized (resin-filled) or reconstituted turquoise | How to tell: Most turquoise on sale today is treated. Reconstituted pieces are ground turquoise in plastic: very uniform color, light for their size. | The risk: Acceptable if disclosed; worth less than natural |
| Citrine clusters and geodes | Really: Heat-treated amethyst | How to tell: Burnt-orange tips on a white or colorless base. Natural citrine is rare, usually pale yellow and often smoky. | The risk: Accepted treatment, but shouldn't be sold as natural citrine |
| Aura quartz (aqua, angel, flame, rainbow) | Really: Real quartz with a vapor-deposited metal coating | How to tell: Metallic rainbow sheen; under a loupe, white worn spots and pits along edges and points. | The risk: Coating scratches and wears off |
| Hot pink, purple, blue or teal agate; black onyx | Really: Dyed agate or chalcedony | How to tell: Colors not found in nature, with dye concentrated along bands and cracks; black onyx is almost always dyed. | The risk: Dye can fade in sun or come off with alcohol |
| Crackle, 'fire and ice' or rainbow quartz | Really: Quartz heated, quenched in cold water and dyed | How to tell: A dense web of internal cracks, with color sitting in the cracks and clear quartz between them. | The risk: Treated and weakened |
| Malachite | Really: Resin or plastic imitation | How to tell: Simple, blocky stripes or 'eyes' without natural geometry, a plastic look, and light for its size (real malachite is heavy). | The risk: Paying malachite prices for plastic |
| Amber | Really: Plastic, or copal (younger resin) | How to tell: Real amber floats in fully saturated salt water where most plastics sink, and builds static when rubbed on wool. | The risk: Paying amber prices for plastic or copal |
| Blue, green, red or yellow 'obsidian' | Really: Usually manufactured glass | How to tell: Natural obsidian is mostly black, brown or green and rarely brightly colored. Bubbles occur in both, so they don't settle it. | The risk: Glass sold as a natural stone |
| Moldavite | Really: Green glass, including 'African moldavite' | How to tell: Real moldavite has worm-like inclusions, many stretched bubbles and chaotic flow lines; fakes look clearer, brighter and more uniform, and they're cheap. | The risk: High value, frequent fraud |
| Bismuth crystals | Really: Lab-grown from molten bismuth, which is normal | How to tell: Stair-stepped 'hopper' shape with a rainbow oxide film; natural hopper crystals are virtually unknown. | The risk: Not fake unless called natural |
| Red, blue, pink or green tiger's eye | Really: Dyed or heat-treated tiger's eye | How to tell: Natural tiger's eye is golden brown; natural blue-gray 'hawk's eye' is subtle. Vivid colors are dyed or heated. | The risk: Treated; dyes can fade |
| Bright pink or neon fluorite | Really: Often dyed, coated or plastic-impregnated | How to tell: Pink fluorite is rare. Look for dye in cleavage cracks and worn coatings. 'Rainbow fluorite' banding is natural. | The risk: Paying for color that isn't natural |
| Sea glass | Really: Glass tumbled, sandblasted or acid-etched by machine | How to tell: Genuine sea glass has a frosted patina with small 'C'-shaped marks and rounded edges; artificial pieces are uniform in texture and shape. | The risk: Paying collector prices for craft glass |
| Magnetic 'hematite' beads | Really: Man-made magnetic material ('hematine') | How to tell: Natural hematite isn't strongly magnetic and leaves a reddish streak. | The risk: Naming only; harmless |
| Jet-black 'smoky quartz' | Really: Colorless quartz irradiated to black | How to tell: Opaque black crystals, often on white bases, and uniformly dark lots. Natural smoky quartz is usually translucent brown. | The risk: Accepted treatment; should be disclosed |
| 'Natural' quartz and amethyst clusters | Really: Lab-grown crystal clusters | How to tell: Every piece nearly identical, too-clean crystals, fuzzy or unnatural faces, and a low price. | The risk: Lab-grown sold as natural |
Also watch for fibrous satin spar sold as “selenite” (both are gypsum, which dissolves in water), “rainbow moonstone” (really a variety of labradorite), dyed jasper sold as “Swiss lapis”, and carnelian made by heating pale chalcedony.
8 Checks You Can Do at Home
- 1
Check the price and the seller
A price far below the natural stone's usual price is the biggest red flag. Buy from sellers who disclose treatments; in the US they are required to.
- 2
Use a 10× loupe
Round bubbles and swirls point to glass, mold marks and rounded facet edges to molded glass, dark lines of color in cracks to dye, and worn edges to a coating. Natural glasses such as obsidian and moldavite have bubbles too.
- 3
Ask if the color exists in nature
Neon pink agate, vivid blue tiger's eye, perfectly even glitter and bins of identical pieces are warning signs.
- 4
Swab test for dye
Rub acetone or rubbing alcohol on a hidden spot with a cotton swab. Color on the swab means dye. It can remove dye and damage finishes, so never use it on resin or plastic.
- 5
Magnet test
A strongly magnetic polished 'hematite' bead is man-made hematine.
- 6
Heft and floating
Amber floats in fully saturated salt water while most plastics sink. Resin 'malachite' and 'turquoise' feel light for their size.
- 7
UV flashlight
Fillers and treatments sometimes glow differently under UV. Never look into the light: short-wave UV can damage your eyes.
- 8
Skip the scratch test
Scratching can crack or chip a finished stone. Use it only on rough, on a hidden spot, if at all.
When to use a gem lab
Use a lab for anything priced as natural, rare or valuable: moldavite, natural citrine, untreated turquoise, large amber or heirlooms. Labs use magnification, Raman and infrared spectroscopy and chemical analysis to detect dyes, coatings, fillers and glass. A GIA identification report for quartz, turquoise and similar stones costs from $75 for small stones to $290 for pieces of 100–999 g (fees effective July 2026). Seller “certificates of authenticity” are easy to fake.
What sellers must tell you (US)
The FTC's Jewelry Guides require sellers to disclose a treatment that isn't permanent, needs special care, or significantly affects value. Lab-grown and imitation stones must be labeled with words like “laboratory-grown”, “imitation” or “simulated”; “faux” isn't enough. Using a gem's name for something that isn't that mined stone is deceptive.
Real-vs-Fake Guides for Gemstones
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Real vs Fake Crystal Questions
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Start with the price and whether the seller discloses treatments. Under a 10× loupe, look for bubbles, swirls and mold marks (glass), dye pooled in cracks (dyed stone) and worn metallic film at edges (coated aura quartz). Ask whether the color exists in nature, and use simple checks such as a magnet for hematite, salt water for amber and a swab for dye. For valuable pieces, use a gem lab.
No, both are man-made glass. Opalite imitates opal or moonstone and goldstone is glass with copper crystals. They're fine to buy as glass, but shouldn't be sold as opal, moonstone, sunstone or aventurine.
Most citrine on the market is heated amethyst or smoky quartz. Natural citrine is rare and usually pale yellow, often smoky. Orange-tipped clusters and geodes with white bases are almost always heated amethyst. Heating is an accepted, stable treatment, but it should be disclosed.
The quartz is real, but the rainbow color is a thin metal coating (gold for aqua aura, titanium for flame aura) applied in a vacuum chamber. The coating can scratch or wear off, especially on points and edges.
Most turquoise sold today is stabilized or otherwise treated. Cheap bright 'turquoise' is often dyed howlite or magnesite: it's softer, shows white inside chips and has dye in its cracks. 'White turquoise' is undyed howlite. Reconstituted turquoise is ground turquoise mixed with plastic.
No source reports a health risk from normal handling. The risks are paying too much and care problems: dyes fade in sun or dissolve in alcohol, coatings scratch, heat-treated citrine can fade with heat, and selenite (gypsum) dissolves in water.
No. Lab-grown crystals have essentially the same chemistry and properties as natural ones; imitations like glass or plastic only look similar. Both are legal to sell if labeled: US rules require words like 'laboratory-grown' or 'imitation', and 'faux' isn't enough.
For anything priced as natural, rare or valuable: moldavite, natural citrine, untreated turquoise, large amber or heirlooms. A GIA identification report for quartz, turquoise and similar stones starts at $75, so a lab usually costs more than an inexpensive tumbled stone is worth.
Sources
- GIA: An introduction to gem treatments
- GIA: Imitation diamonds and other gems
- GIA: Is citrine treated?
- International Gem Society: Glass gemstones
- International Gem Society: Turquoise
- International Gem Society: Aqua aura quartz and vapor deposition
- International Gem Society: Amber
- International Gem Society: Identifying gemstone treatments
- Geology.com: Goldstone
- Geology.com: Moldavite
- International Sea Glass Association: Genuine vs artificial
- FTC Jewelry Guides (16 CFR Part 23)