By the CS Minerals Wholesale Team · Last updated
Fake gems are usually called simulants or imitations when they are a different material that only looks like the real stone, such as glass or cubic zirconia imitating diamond. Stones made in a laboratory with the same chemistry as the natural gem are called synthetic, lab-grown or lab-created, and they are not technically fake. Natural stones whose color or clarity was altered are called treated or enhanced, and stones glued together from parts are called composite or assembled stones, such as doublets and triplets.
The words matter because customers mix them up, and regulators do not. In the United States, the FTC Jewelry Guides set out how these stones should be described in advertising and at the point of sale, and similar consumer protection rules apply in the UK, the EU and Australia. If you sell stones, knowing what fake gems are called, and which word applies to which product, is part of selling honestly.
What Are Fake Gems Called? The Four Main Categories
“Fake” is a customer word, not a trade word. In the trade, anything that is not a natural, untreated stone falls into one of four groups. The table below sets them side by side.
| Category | Also called | Same chemistry as the natural gem? | Example |
|---|---|---|---|
| Synthetic | Lab-grown, lab-created, laboratory-grown, [maker]-created | Yes | Lab-grown diamond, synthetic ruby, synthetic quartz |
| Simulant | Imitation, faux, look-alike | No | Cubic zirconia imitating diamond, glass imitating emerald |
| Treated natural | Enhanced | Yes, it is the natural stone | Heated sapphire, dyed agate, heat-treated amethyst sold as citrine |
| Composite | Assembled, doublet, triplet | Partly | Opal doublet, garnet-topped doublet |
Two more terms sit at the edges: reconstituted or reconstructed stones, made from natural fragments or powder bound together (common with turquoise and amber), and man-made materials with their own names, like goldstone or opalite, which are glass products sold under trade names.
Synthetic, Lab-Grown and Lab-Created Gems
A synthetic gem is grown by people but has essentially the same chemical composition, crystal structure and optical properties as its natural counterpart. A synthetic ruby is corundum. A lab-grown diamond is carbon in the diamond structure. This is why a basic refractometer test often cannot tell them apart.
Are synthetic gems fake?
Not in the technical sense. They are real rubies, sapphires or diamonds, just not mined ones. What makes them a problem is selling them without disclosure. A synthetic stone sold as natural is a misrepresentation, even though the material is correct.
Common synthetics
- Lab-grown diamond, made by high pressure high temperature (HPHT) or chemical vapor deposition (CVD) methods.
- Synthetic corundum (ruby and sapphire), made for over a century and used widely in watches and jewelry.
- Synthetic emerald, spinel and alexandrite, found in jewelry at many price points.
- Synthetic quartz, grown in large volumes for electronics and sometimes sold in colors that are rare in nature.
- Moissanite, which is found in nature only in tiny amounts, so gem-quality moissanite is lab-made. It is sold under its own name as a diamond alternative.
Simulants and Imitations: What Most Fake Gems Are Called
A simulant or imitation is a material that looks like a gem but is something else. When most people ask what fake gems are called, this is what they mean.
Common simulants
- Glass, the oldest simulant of all. Historically, cut lead glass used in jewelry was called paste, and glass stones with a foil or coating backing are often called rhinestones.
- Cubic zirconia (CZ), a lab-made material used mainly to imitate diamond. CZ is itself a synthetic material, but as a diamond look-alike it is a simulant.
- Plastic and resin, used in costume jewelry and sometimes to imitate amber, turquoise or coral.
- Other natural stones, such as dyed howlite imitating turquoise, or colorless topaz or quartz imitating diamond. The stone is natural, but the name it is sold under is not.
Faux, costume and fashion jewelry
In retail, faux, costume and fashion jewelry are common descriptions for pieces set with simulants. These words are fine as long as the customer clearly understands the stones are not natural gems.
Treated and Enhanced Gemstones
A treated gemstone is a natural stone whose appearance was changed after mining. Treatment is extremely common, and many treatments are accepted and stable. They are not fakes, but disclosure rules apply.
Common treatments
- Heating: sapphire, ruby, tanzanite, and amethyst turned into the yellow and orange quartz sold as citrine.
- Dyeing: agate, chalcedony, howlite, some jade and some quartz.
- Oiling or resin filling: emerald clarity enhancement.
- Irradiation: some blue topaz and some smoky quartz.
- Coating: aura quartz and some coated topaz, where a thin metal or colored layer changes the surface look.
- Stabilizing: soft, porous turquoise impregnated with resin to harden it.
Treatment affects value. Our article on whether crystals are worth money explains how buyers price treated and untreated material differently.
Composite and Reconstituted Stones
A composite or assembled stone is built from two or more parts glued or fused together. A doublet has two layers, and a triplet has three. Opal doublets and triplets, where a thin slice of real opal sits on a dark backing under a clear cap, are the best-known example and are sold legitimately when labeled.
A reconstituted stone is made from natural fragments or powder bonded into a solid block. Reconstituted turquoise and pressed amber are common. Again, the rule is simple: say what it is.
What Do You Call Fake Crystals?
Crystal shops use slightly different language from jewelers, because most crystals are sold as specimens, points, tumbles and decor rather than as faceted gems. Here are the terms you will see and what they actually mean.
- Glass or man-made glass: clear or colored glass sold as quartz spheres or points. Names like “smelted quartz,” “cherry quartz” and “blue obsidian” are frequently glass.
- Opalite and goldstone: man-made glass products with trade names. Fine to sell, not natural stones.
- Dyed: real stone with added color, most often agate, howlite and some quartz.
- Heat-treated: real stone with color changed by heat, most often amethyst sold as citrine.
- Coated or aura: real quartz with a thin metal layer.
- Lab-grown or synthetic quartz: real quartz made in a lab.
- Resin or composite: resin blocks with crushed stone, sometimes sold as “natural” slabs.
So what do you call fake crystals? If it is a different material, call it by that material (“glass,” “resin”). If it is real but altered, name the treatment (“dyed agate,” “heat-treated amethyst”). For a practical list of which crystals are most often misrepresented and how to check them, see our crystal buyer’s checklist.
FTC Jewelry Guides: How US Sellers Must Describe These Stones
In the United States, the Federal Trade Commission publishes the Guides for the Jewelry, Precious Metals, and Pewter Industries, found at 16 CFR Part 23 and usually called the FTC Jewelry Guides. They were last substantially revised in 2018. The FTC also publishes plain-language business guidance on gem advertising on its website. What follows is a general summary, not legal advice. Always read the current official text.
Lab-grown stones need a clear qualifier
The Guides say a laboratory-made stone should be described with a word that makes its origin clear, such as “laboratory-grown,” “laboratory-created,” “[manufacturer name]-created” or “synthetic,” placed with the name of the gem. The 2018 revision also warned against using “cultured” for lab-grown diamonds without a clear qualifier, because shoppers may confuse it with natural.
Words that imply natural
The Guides caution against using words like “real,” “genuine” or “natural” for stones that are lab-created or imitation. An imitation should be described so the buyer understands it is an imitation.
When treatments must be disclosed
Under the Guides, sellers should disclose a gemstone treatment when it is not permanent, when it creates special care requirements, or when it significantly affects the value of the stone. Dyed agate and heat-treated citrine fall into the value category for most buyers, and coated stones often need special care, so disclosure is the safe and honest default.
Outside the US
Other markets have their own rules. The UK has consumer protection law and the Advertising Standards Authority, the EU has unfair commercial practices rules, and Australia has the ACCC and Australian Consumer Law. International trade bodies such as CIBJO publish nomenclature guidance too. The principle across all of them is the same: the buyer must not be misled about what the stone is. If you sell online across borders, our guide on how to sell crystals online covers listings and descriptions, and our article on whether you need a license to sell crystals covers the business side.
Why the Right Name Changes the Price
Each category sits at a different price level, and that is the real reason naming matters. A buyer who pays natural prices for a synthetic or a simulant has been harmed, even if the stone is pretty. Customers usually understand this intuitively once the words are explained.
As a general rule, and with plenty of exceptions by species and quality, the order from highest to lowest value tends to look like this:
- Natural, untreated stones with documentation, at the top.
- Natural stones with accepted, stable treatments, such as heated sapphire or heat-treated amethyst sold as citrine.
- Synthetic or lab-grown stones, whose prices have dropped a lot as production has grown, especially for diamonds.
- Composite and reconstituted stones, which use small amounts of natural material.
- Simulants such as glass, CZ and plastic, at the bottom.
None of this makes the lower tiers bad products. Glass jewelry and lab-grown stones serve real customers at real price points. The damage comes only when a stone is sold one tier higher than it belongs. Clear names keep every sale in the right tier, which is also why returns and complaints drop when labels are precise.
For crystal shops the same logic applies at a smaller scale. A natural citrine point, a heat-treated citrine cluster and a yellow glass point may look similar on a shelf, but they belong at three different prices and need three different labels.
How to Label Stones in Your Shop
A simple labeling system protects you and helps customers choose. Use the same structure on shelf tags, product pages and invoices.
- Name the material first: “Amethyst,” “Agate,” “Glass,” “Cubic zirconia.”
- Add the origin qualifier if not natural: “Lab-grown sapphire,” “Man-made opalite.”
- Add the treatment: “Heat-treated amethyst (citrine color),” “Dyed agate,” “Titanium-coated quartz.”
- Add care notes when needed: “Coating may wear. Clean with a soft dry cloth.”
- Keep the supplier’s description on file so your label matches what you were told in writing.
Customers who are shown clear labels usually trust a shop more, not less. For high-value stones, our guide to the most expensive gemstones in Brazil shows why paperwork and precise naming matter even more at the top of the market.
Frequently Asked Questions
What are fake gems called?
Fake gems are usually called simulants or imitations. These are materials such as glass, cubic zirconia or plastic that look like a gem but are a different substance. Lab-made stones with the same chemistry as the natural gem are called synthetic or lab-grown, and they are not fake in the technical sense.
What do you call fake crystals?
Fake crystals are usually glass or man-made materials, so the honest name is the material itself, such as “glass,” “opalite” or “resin.” Real crystals that were altered are named by treatment, such as “dyed agate,” “heat-treated amethyst” or “coated aura quartz.”
Is a lab-grown gem a fake gem?
No. A lab-grown gem has essentially the same chemistry and structure as the natural stone, so it is real material, just not mined. It must be sold with a clear qualifier such as “lab-grown” or “laboratory-created.”
More Questions
What is the difference between synthetic and simulant?
A synthetic is the same material as the natural gem, made in a lab. A simulant is a different material that only looks like the gem. Lab-grown diamond is synthetic; cubic zirconia sold as a diamond look-alike is a simulant.
Are treated gemstones considered fake?
No. Treated gemstones are natural stones whose color or clarity was improved, for example by heat or dye. Under the FTC Jewelry Guides, treatments should be disclosed when they are not permanent, need special care or significantly affect value.
What is a doublet or triplet gem?
A doublet is a stone made from two layers glued or fused together, and a triplet has three. Opal doublets and triplets are common and legitimate when labeled. They should never be sold as solid stones.
Buy Natural Brazilian Crystals With Honest Descriptions
CS Minerals is a Brazilian crystal, mineral and natural stone wholesaler based in Soledade, Rio Grande do Sul, with 25 years in the trade. We ship wholesale orders worldwide from a US$100 minimum and sell live from our warehouse Monday to Friday, 8am to midnight Brazilian time on Instagram @csminerals, so you can see each lot and ask what it is before you buy. Start with our how to order wholesale crystals guide or browse the wholesale collection.