Are lab-grown gems real gemstones?
Yes. A lab-grown sapphire is , aluminium oxide, exactly what a mined sapphire is; a lab diamond is carbon in the diamond lattice, exactly what a mined diamond is. GIA describes a synthetic gem as sharing virtually all the chemical, optical and physical characteristics of its natural counterpart (GIA). Hardness, , the way light moves through it: identical, because it is the same substance. What differs is where the crystal formed, what got trapped inside it while it grew, what it costs, and what someone will pay you for it later. That last one is close to nothing for both, under about a carat.
The name has to say so. Under the US FTC Jewelry Guides, a gem name used for a lab-grown stone must be "immediately preceded with equal conspicuousness" by "laboratory-grown", "laboratory-created", "[manufacturer name]-created" or another word of like meaning (16 CFR 23.25(b)). Paragraph (c) of the same rule lists "synthetic" alongside them, and the FTC says "faux" is not an adequate disclosure. A look-alike made of a different material may use the gem's name only after "imitation" or "simulated".
Gem, mineral or simulant: which is which
| Gem | Mineral | Lab-grown version (the same mineral) | Common simulants (a different material) |
|---|---|---|---|
| Diamond | Diamond (carbon) | Lab-grown diamond, grown by HPHT or CVD | Moissanite, cubic zirconia, colourless sapphire, YAG, glass |
| Ruby and sapphire | Corundum (aluminium oxide) | Lab ruby and lab sapphire: flame fusion (the cheapest and most common method), flux, pulled or hydrothermal | Glass, plastic, lab spinel |
| Emerald | Lab emerald: flux-grown, or hydrothermal (in jewellery since 1960) | Glass, plastic | |
| Alexandrite | Chrysoberyl | Lab alexandrite: Czochralski (pulled), floating zone or flux | Colour-change lab spinel and lab sapphire |
| Spinel | Spinel | Lab spinel: flame fusion | Glass. Lab spinel is itself widely used to imitate other gems |
| Amethyst, citrine, rock crystal | Quartz (silicon dioxide) | Lab quartz: hydrothermal, the only method that works for quartz | Glass |
| Opal | Opal (hydrated silica) | Lab opal: the Gilson process, from the 1970s. Some lab opal also contains other compounds, such as polymer | Glass, plastic imitation opal |
Growth methods and the alexandrite and spinel imitations: GIA, An Introduction to Synthetic Gem Materials. Diamond simulants: GIA 4Cs. Glass and plastic imitations: GIA, An Introduction to Imitation Diamonds & Other Gems; plastic imitation opal: Gems & Gemology, Spring 2018. Moissanite and cubic zirconia are lab-made materials in their own right: honest when sold under their own names, simulants when they stand in for diamond. For the full list of what is and is not grown, see which gems can be lab-grown.
A third kind of stone is neither a plain mined ruby nor a lab-grown one: glass-filled (composite) ruby, corundum held together with lead glass. The FTC says it must not be sold as plain "ruby", "treated ruby" or "lab-grown ruby" unless the listing clearly discloses that it does not have the same characteristics as ruby and needs special care (16 CFR 23.25(d)). More on this in gem treatments explained.
New to all this? Start with the gem world, laid out.
Same mineral, different birthplace
Mined corundum grew over millions of years in rock; lab corundum grows in days to months in a furnace by one of several methods. Flame fusion (Verneuil, 1902) drips powdered alumina through a flame onto a growing boule; it is the cheapest, and it is what loose lab sapphire and ruby sold for a few dollars a stone on Amazon are. Flux and hydrothermal growth are slower and dearer and produce stones that look more like mined material inside. Lab diamonds grow either by HPHT (high pressure, high temperature, mimicking the mantle) or CVD (a carbon-rich gas depositing onto a ); lab diamond melee on Amazon is listed as either. The US definition of diamond does not ask where the stone formed: it is "a mineral consisting essentially of pure carbon crystallized in the isometric system" (16 CFR 23.12).
What you can see, and what you cannot
You cannot see the difference by eye. Mined stones usually carry , colour zoning and silk; lab stones are usually cleaner and more evenly coloured, which is why a dead-even, glass-clear blue in a cheap "sapphire" is itself a hint that it grew in a furnace. Flame-fusion corundum can show under 10x magnification, the one tell a loupe can find; mined corundum grows in straight angular zones. Lab diamonds are separated from mined ones only by laboratory instruments that read patterns and trace nitrogen; a thermal diamond tester says "diamond" for both, and says "diamond" for moissanite too unless it is the electrical kind.
Price and resale
Lab corundum is the cheapest lab gem to make: GIA calls flame fusion the least expensive and most common way to grow it (GIA). For per-carat figures, lab against mined, gem by gem, see lab vs mined gem prices, worked out from each day’s listing prices. Lab diamond has fallen to a small fraction of mined diamond and keeps falling as production scales: wholesale lab-grown prices fell 26% in 2025 on Edahn Golan's index, which is down 96% since he began tracking in 2018 (JCK, 10 August 2026). The honest consequence: buy lab stones to wear and to set, not as a store of value. Mined stones under a carat are not much of a store of value either, whatever the counter says.
What to buy for what
- A stone to set yourself: lab corundum, oval or cushion, calibrated to a standard mounting size. Cheap enough to ruin one learning.
- Pave or accent stones: lab diamond melee, sold by millimetre size; run a tester on arrival.
- A big white stone on a budget: moissanite, which is not a diamond and has more fire than one; see moissanite vs lab diamond.
- Something to hold value: none of the above. A graded mined stone of good colour over a carat, from a dealer, with a report.
Frequently Asked Questions
Are lab-grown gems real gemstones?
Yes. A lab-grown ruby or sapphire is corundum and a lab-grown diamond is diamond, the same mineral as the mined stone. Under the US FTC Jewelry Guides (16 CFR 23.25), it must be sold as laboratory-grown, laboratory-created, [manufacturer name]-created or with a word of like meaning, such as synthetic, so you know it was not mined.
Can a jeweller tell lab-grown from natural?
Not by eye, and usually not with a loupe. Lab diamonds are separated from mined ones with laboratory instruments that read growth patterns and trace elements; lab corundum from the cheapest growth method (flame fusion) can show curved growth lines under magnification that mined stones never have, which is the one tell a good loupe user can find.
Do lab-grown stones lose value?
They have little resale value to begin with, and lab diamond prices have fallen steeply as production scaled. Buy lab stones to wear, not to hold; that is also true of most mined stones under a carat.
Is "lab-created" the same as "simulated"?
No. Lab-created means the same mineral, grown rather than mined: lab sapphire is corundum, lab diamond is carbon. Simulated means a different material that looks similar: cubic zirconia and moissanite simulate diamond, glass simulates everything. A listing that says "created" without "lab" is worth a second read.
Sources
- US FTC Jewelry Guides, 16 CFR 23.25, misuse of "ruby", "sapphire", "emerald", "gem" and similar words (paragraphs (b), (c) and (d)): law.cornell.edu
- US FTC Jewelry Guides, 16 CFR 23.12, definition and misuse of the word "diamond": law.cornell.edu
- Weldon, R., "An Introduction to Synthetic Gem Materials", GIA Gem Encyclopedia: gia.edu
- Weldon, R., "An Introduction to Simulants or Imitation Gem Materials", GIA Gem Encyclopedia: gia.edu
- GIA 4Cs, "What Are Simulated Diamonds?": 4cs.gia.edu
- "New Plastic Imitation Opal from Kyocera", Gems & Gemology Lab Notes, Spring 2018: gia.edu
- Cooley, S., "Lab-Grown Diamond Wholesale Prices Are in Freefall; Retail Margins May Be Next", JCK, 10 August 2026: jckonline.com