The sparkle is hypnotic. The price looks tempting. One question blocks the purchase: is this gemstone truly natural, or a brilliant lab creation that only looks the part?
The answer sits in a handful of observable signs and a few trustworthy documents. From diamond vs moissanite to ruby, sapphire and emerald, here is how to separate real gemstones from synthetics today, based on standards and lab data that hold up in a store or online.
Real vs synthetic gemstones: meanings that change how you shop
Words matter. The U.S. Federal Trade Commission updated its Jewelry Guides in July 2018 to allow the word “diamond” for laboratory-grown stones when the seller clearly discloses terms like “laboratory-grown” or “created” (FTC, 2018). That single detail changes labels and receipts.
On terminology, ISO 18323:2015 sets a global baseline: a synthetic diamond is man-made, with the same composition and structure as natural diamond, and should be described with qualifiers such as “laboratory-grown” (ISO 18323:2015). That is what honest disclosure looks like.
History gives context. Synthetic ruby and sapphire emerged with the Verneuil flame-fusion process in 1902. General Electric announced the first reproducible HPHT synthetic diamonds in 1954. Chemical Vapor Deposition has expanded gem-quality production since the 1990s.
So yes, a lab-grown gem can be real gem material. The question shoppers care about is origin. Natural formed in the earth. Synthetic grew in a factory. Both can be beautiful. Pricing and rarity differ.
Quick visual checks that reveal origin signals
Clarity tells stories. Natural gemstones often show irregular inclusions or growth features. Lab-grown often shows consistent patterns tied to the method used.
Moissanite vs diamond trips many buyers. Moissanite has stronger fire because its dispersion is about 0.104, versus 0.044 for diamond – roughly 136 percent greater. That extra rainbow sparkle looks pretty, yet different.
Foiled by thermal testers? Many moissanites pass older heat-based diamond testers. A combined thermal and electrical conductivity tester is needed for a confident diamond result.
A 10x loupe helps. Diamonds are singly refractive. Moissanite is doubly refractive. Look along a facet junction: double lines hint moissanite. Keep the stone clean, wipe fog and oil before looking.
Weight can guide the eye. Diamond has a density around 3.52. Moissanite sits near 3.22. Same size, slightly lighter feel. Small, but noticeable for pros.
As for color gems, flame-fusion sapphires and rubies may show curved growth lines under magnification, while natural corundum shows angular zoning. That single cue has saved many wallets.
Skin-level checks help, yet they do not replace instruments. Still, they filter risky buys fast.
Here is a compact checklist for everyday use :
- Look for consistent perfection. Flawless, big and cheap rarely aligns with natural origin.
- Check the sparkle. Excess rainbow fire and doubled facet lines point to moissanite, not diamond.
- Scan inclusions at 10x. Curved growth lines suggest flame-fusion corundum.
- Ask for written disclosure on the receipt: “laboratory-grown” or “natural”, plus the species.
- Request a grading report from a recognized lab before paying.
Trusted tests and reports that settle the question
Refractive index is foundational. Diamond is around 2.42. Moissanite sits between 2.65 and 2.69. Sapphire and ruby (corundum) read near 1.76 to 1.77. Spinel approximates 1.718. A standard refractometer confirms species, while advanced tools go further.
Fluorescence gives clues, not verdicts. The Gemological Institute of America notes that about 25 to 35 percent of diamonds show fluorescence under longwave UV, and a smaller fraction show medium to strong reactions (GIA). Patterns differ by growth method in lab-grown diamonds, useful for experts.
Spectroscopy and microscopy seal cases. HPHT-grown diamonds often carry metallic flux inclusions or specific growth patterns. CVD-grown can show layered growth and characteristic strain. These are lab-level tells, seen with the right instruments.
Paperwork is practical. Reputable grading reports use explicit language: “laboratory-grown diamond” or “natural diamond”, with growth method when relevant. GIA, IGI, AGL and other recognized labs report species, treatments and, for diamonds, type classification that can aid origin detection.
Treatments belong on the record. Emeralds are often clarity-enhanced with oils or resins. Corundum may be heat treated. Disclosure is part of ethical sales and protects resale value.
Prices, red flags and how to buy with confidence
Pricing tells a story. A colorless, 1-carat lab-grown diamond often costs far less than a natural of similar grade. A natural stone priced like a lab-grown deserves scrutiny. The reverse too.
Documentation is non-negotiable. The 2018 FTC guidance calls for clear, conspicuous disclosure of laboratory-grown status in ads and at point of sale (FTC, 2018). ISO 18323:2015 backs that approach for consumer confidence. Ask to see this disclosure before you reach for a card.
Receipts matter later. Ensure the printed receipt states the gem species, origin claim, treatments and the report number if present. That one slip of paper supports trade-in and insurance.
Independent verification adds calm. A quick check by a credentialed gemologist, with a refractometer and a polariscope, closes most identification gaps on the spot. For higher values, a full lab report removes doubt.
One last practical step changes outcomes. Set a return window in writing, tie the sale to a grading report, and keep the communication in the same thread. It sounds simple, yet it definitly saves time and money when the sparkle is strong and the story needs proof.