Do Lab-Grown Diamonds Pass a Diamond Tester? Yes — Here's Why

Quick answer: Yes. A lab-grown diamond passes any standard thermal or electrical diamond tester, because it is a real diamond — chemically, physically, and optically identical to a mined stone. Testers distinguish diamond from imitations like cubic zirconia and moissanite; they cannot (and should not) distinguish lab-grown from mined, because both are carbon crystallized in the same structure.

How do diamond testers work?

Handheld testers measure thermal conductivity — how fast heat moves through a stone. Diamond conducts heat faster than any common imitation, so a real diamond, lab-grown or mined, reads as "diamond." Dual testers add an electrical conductivity check to catch moissanite, which conducts heat like diamond but electricity differently. Lab-grown diamonds pass both checks.

Then how do labs tell lab-grown and mined apart?

Only specialized gemological instruments — the kind used by grading labs like IGI and GIA — can detect the subtle growth patterns and trace elements that differ between a stone grown above ground and one mined from it. That's why every Zack & Elle diamond over one carat comes with an IGI certificate and a laser inscription on the girdle: your independent proof of exactly what the stone is.

Will a jeweler know my studs are lab-grown?

Not by eye, and not with a standard tester. A jeweler with a loupe can read the laser-inscribed IGI number and look up the report — which will state it is a laboratory-grown diamond with its exact carat weight, color, and clarity. That transparency is the point: you know precisely what you own, and you paid a fraction of the mined price for it.

The bottom line

If someone tells you lab-grown diamonds "fail the tester," they're describing simulants — CZ or moissanite — not lab-grown diamonds. Ours are IGI-certified D–F color, VS1 clarity stones that test as diamond because they are diamond.

See the proof in person: lab-grown diamond studs from $325, or book a private viewing in NYC's Diamond District. Free insured FedEx shipping and 30-day returns on every order at zackandelle.com.