Only for the Wealthy

Buying guide

Spotting fake diamonds and jewelry

Updated October 21, 2026 · Written by the Only for the Wealthy editors · General information, not legal or financial advice

Most jewelry problems aren’t glass sold as diamond. They’re undisclosed treatments, lab-grown stones sold as natural, overstated weight, or plated metal sold as solid. Paperwork and disclosure protect you more than home tests do.

1. Know the 4Cs, and get them in writing

The FTC explains diamonds are evaluated by color (GIA scale D to Z), cut, clarity (GIA scale from flawless to I3), and carat weight [1]. Ask the seller to put origin, weight, treatments, and care requirements in writing. The FTC says that if a seller won’t, consider working with someone else [1].

2. Verify the grading report

  • If a stone comes with a GIA report, look the number up on GIA Report Check and compare the details (shape, measurements, weight, grades) to the stone and the paperwork [2].
  • Many GIA-graded diamonds have the report number laser-inscribed on the girdle; ask a jeweler to show it under magnification.

3. Ask about treatments

Fracture filling and laser drilling are “clarity enhancements” that the FTC notes lessen a stone’s value [1]. The FTC Jewelry Guides say sellers must truthfully represent treatment, origin, quality, and metal content [3][4].

4. Natural, lab-grown, or simulant?

  • Lab-grown diamonds are real diamonds, but the FTC Jewelry Guides require that laboratory-created stones be clearly identified as such [4].
  • Simulants (such as cubic zirconia or moissanite) are different materials. Some basic handheld testers can’t reliably tell every simulant from diamond. For a meaningful purchase, rely on a lab report and a qualified gemologist.

5. Check the metal

  • Look for karat or fineness marks (e.g., 14K, 18K, 925, PLAT/PT). The Guides set rules for how gold, silver, and platinum may be marked and described, including plated items [4].
  • A quality mark should come with the maker’s trademark; ask about it if it’s missing.

6. Seller and returns

Check reviews and complaints, and get the refund and return policy in writing before you buy [1].

Sources

  1. FTC: Buying Gemstones, Diamonds, and Pearls
  2. GIA Report Check (verify a GIA grading report number)
  3. FTC: Jewelry Guides overview
  4. eCFR: 16 CFR Part 23, Guides for the Jewelry, Precious Metals, and Pewter Industries

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