Let's answer the question before the first paragraph is over: yes, lab grown diamonds are real diamonds. Not "basically real." Not "real-ish." Real — by chemistry, by physics, by federal regulation, and by the standards of every major gemological laboratory on earth.
We've spent more than thirty years behind counters in New York's Diamond District, and this is the question we hear most often — usually asked quietly, like there might be an embarrassing answer. There isn't. But there is a genuinely interesting one, and understanding it will make you a sharper diamond buyer no matter what you end up purchasing.
What Makes a Diamond "Real"?
Strip away the marketing and a diamond is a simple thing: carbon atoms arranged in a cubic crystal lattice. That specific structure — each carbon atom bonded to four neighbors in a rigid, repeating pattern — is what creates every property we prize. The hardness (10 on the Mohs scale, the hardest natural material known). The fire. The brilliance. The way it shrugs off scratches that would ruin any other gemstone.
Notice what's missing from that definition: where the carbon crystallized. A diamond formed 100 miles underground over a billion years and a diamond grown in a New Jersey lab over eight weeks are the same material in the way ice from your freezer and ice from a glacier are both ice.
This isn't just our opinion. In 2018, the U.S. Federal Trade Commission revised its Jewelry Guides and removed the word "natural" from its definition of a diamond — because, in the FTC's words, lab-grown stones have "essentially the same optical, physical, and chemical properties as mined diamonds." When the federal government's truth-in-advertising agency says it's a diamond, it's a diamond.
Lab Grown Diamonds: The Science Behind Them
"Grown" is the right word. Labs don't assemble or fabricate diamonds — they create the conditions under which carbon crystallizes, then let nature's own process run. Two methods dominate.
CVD Growth Process Explained
Chemical Vapor Deposition (CVD) starts with a thin slice of diamond — the "seed" — placed in a vacuum chamber filled with carbon-rich gas, usually methane. The gas is heated to a plasma state at around 1,500°F, which breaks the molecules apart. Freed carbon atoms rain down onto the seed and attach to its crystal lattice, layer by atomic layer. Over six to ten weeks, a rough diamond grows — the same way rock candy grows on a string, except the "candy" is the hardest material on the planet.
HPHT Growth Process Explained
High Pressure High Temperature (HPHT) is the older method, and it's exactly what it sounds like: a recreation of the earth's mantle. A carbon source and a diamond seed go into a press that generates roughly 870,000 pounds per square inch of pressure at temperatures above 2,600°F. Under those conditions, carbon has no choice but to crystallize into diamond. HPHT is also used to refine the color of CVD-grown stones.
Carbon Atom Structure: Identical to Natural
Here's the part that settles the argument. Put a mined diamond and a lab grown diamond under an electron microscope and you will see the same thing: carbon atoms in a cubic lattice, bonded identically, spaced identically. Same refractive index (2.42). Same dispersion — the property that splits light into that signature rainbow fire. Same density, same thermal conductivity, same hardness. The only way major labs distinguish them is with specialized deep-UV instruments looking for microscopic growth-pattern differences — and even then, it takes machines, not eyes.
How Lab Diamonds Differ from Diamond Simulants
Much of the "are lab diamonds fake?" confusion comes from lumping them in with simulants — stones that look somewhat like diamonds but are entirely different materials. This is the distinction that actually matters when you're shopping.
Lab Diamond vs Cubic Zirconia
Cubic zirconia is zirconium dioxide — no carbon at all. It's soft by gem standards (8–8.5 Mohs), which means it scratches, clouds, and dulls with everyday wear, often within a couple of years. It's also noticeably denser and has more "rainbow flash" than true diamond fire, which is how trained eyes spot it instantly. A lab created diamond vs cubic zirconia isn't a comparison; it's a category difference. One is a diamond. One is a diamond costume.
Lab Diamond vs Moissanite
Moissanite deserves more respect — it's a legitimate gemstone (silicon carbide) with real durability at 9.25 Mohs. But it isn't diamond. Its dispersion is more than double a diamond's, producing a fiery, disco-ball sparkle that many people find beautiful and others find conspicuously "not diamond." It also tests differently: moissanite fails a proper dual-mode diamond tester. The lab diamond vs moissanite choice is a real decision some buyers weigh on budget — but only one of them is a diamond.
Lab Diamond vs White Sapphire
White sapphire is crystallized aluminum oxide. It's durable (9 Mohs) but optically quiet — a fraction of diamond's brilliance and almost none of its fire. Side by side with any diamond, lab or mined, white sapphire looks soft and glassy. It's the most understated of the simulants, and the easiest to distinguish.
The pattern is simple: simulants imitate a diamond's look. A lab grown diamond doesn't imitate anything — it is the thing.
What Gemologists Say About Lab Diamonds
The institutions that grade the world's diamonds settled this question years ago.
IGI (International Gemological Institute) has graded lab grown diamonds since 2005 and issues full 4C reports — cut, color, clarity, carat — using the same scale applied to mined stones. GIA (Gemological Institute of America), the most famous name in gemology, grades lab-grown diamonds with complete quality reports as well. Neither organization grades cubic zirconia or moissanite as diamonds, because they aren't. Both grade lab-grown diamonds as diamonds, because they are.
Every stone we sell at Laura Milman New York comes with independent certification — it's the first thing we show you, not the last. If you want to understand what those reports mean line by line, our FAQ walks through it, and we're always happy to do it in person.
Do Lab Diamonds Pass a Diamond Tester?
Yes — and this is the demonstration that converts skeptics on the spot.
Standard diamond testers measure thermal conductivity, because diamond moves heat unlike any other gemstone. Touch the probe to cubic zirconia: fail. White sapphire: fail. Touch it to a lab grown diamond: pass, every time — because the tester is detecting the carbon lattice itself, and the lattice is identical. (One nuance: moissanite can fool old thermal-only testers, which is why jewelers use dual testers that add electrical conductivity. Lab diamonds pass those too.)
Come by our counter and we'll put any stone you like on the tester. The beep doesn't lie.
Final Answer: Real Diamond, Real Value
So — are lab grown diamonds real diamonds? By atomic structure, yes. By the FTC's legal definition, yes. By IGI and GIA grading standards, yes. By the diamond tester on our counter, yes.
What lab-grown changes isn't the diamond. It's the economics and the ethics: the same certified stone typically costs 40–60% less than its mined equivalent, with a supply chain you can actually trace. That's why our lab-grown diamond collection sits right alongside the fine, estate, and signed pieces we're known for in New York — and why the honest answer to this question has been good news for every couple who's asked us.
If you're weighing lab against mined in detail — resale, rarity, long-term value, all of it — our lab vs natural diamond comparison covers the tradeoffs without the sales pitch.
Frequently Asked Questions
Are lab grown diamonds considered fake? No. Lab grown diamonds are chemically, physically, and optically identical to mined diamonds — pure crystallized carbon. The FTC legally defines them as diamonds, and gemological labs grade them as diamonds. "Fake" applies to simulants like cubic zirconia, which are different materials entirely.
Can you tell the difference between a lab and natural diamond with the naked eye? No — and neither can a jeweler with a loupe. Distinguishing them requires specialized laboratory instruments that read microscopic growth patterns. To the eye, on the hand, in the light: identical.
Do lab diamonds pass diamond testers? Yes. Standard testers measure thermal conductivity, and lab diamonds conduct heat exactly like mined diamonds because they're the same material. Simulants like CZ fail; lab diamonds pass.
Are lab grown diamonds graded the same way as natural diamonds? Yes. IGI and GIA grade lab-grown diamonds on the identical 4C scale — cut, color, clarity, and carat — and issue full independent reports for each stone.
Will a lab diamond look as brilliant as a mined diamond? Yes. Brilliance comes from the refractive index and the quality of the cut, and lab diamonds share the exact refractive index of mined stones (2.42). A well-cut lab diamond will outshine a poorly cut mined one every time — cut quality, not origin, decides sparkle.
Explore Our Lab Grown Diamond Collection Browse Laura Milman New York's selection of certified lab-grown diamond engagement rings — designed in New York, crafted in Italy.