Lab-Grown Diamonds: The Complete Guide to How They Are Made, Graded and Priced

A lab-grown diamond is crystallized carbon arranged in the same cubic lattice as a mined diamond. It is not a coating, not a look-alike and not a different mineral. GIA describes laboratory-grown diamonds as having essentially the same chemical, optical and physical properties and crystal structure as natural diamonds.

The US Federal Trade Commission agreed in its 2018 revision of the Jewelry Guides. The old definition of "diamond" required the stone to be natural; the revision dropped that word. A lab-grown diamond is a diamond. What the rules require is honesty about origin: the seller must say clearly that it is lab-grown, laboratory-created or made by a named manufacturer.

The only real difference is where and how fast the crystal grew. A mined diamond formed deep in the earth over a very long time. A lab-grown diamond grows in weeks in a controlled chamber. Once it is cut and polished, the two are indistinguishable to the eye and to a standard diamond tester. Our side-by-side breakdown is in lab vs natural diamonds.

HPHT stands for high pressure, high temperature. It recreates, in a press, the conditions under which diamonds form in the earth. A small diamond seed is placed with a carbon source and a molten metal mixture (the "flux") inside a growth cell. Huge presses squeeze the cell while it is heated, the carbon dissolves in the metal and then crystallizes onto the seed.

GIA notes that the first gem-quality lab-grown diamonds were produced by HPHT. Because the flux is metallic, HPHT stones can contain tiny metallic inclusions, which is one of the clues gemologists use to identify them. HPHT crystals tend to grow in a cuboctahedral shape, with a mix of cube and octahedral faces.

CVD stands for chemical vapor deposition. Thin slices of diamond (seed plates) are placed in a vacuum chamber filled with a carbon-rich gas, usually methane mixed with hydrogen. Microwaves or another energy source turn the gas into a plasma, and carbon atoms settle onto the seeds layer by layer. The crystals grow upward as flat, tabular blocks.

GIA reports that most lab-grown diamonds passing through its laboratories today are grown by CVD, and that most of those receive a post-growth HPHT treatment to remove a brownish tint. That treatment is permanent and is disclosed on grading reports, which state whether a stone is "as grown" or has been treated after growth. It does not make the stone any less a diamond.

For a buyer, the method matters much less than the finished grades. A well-cut E VS1 stone looks the same whether it came from a press or a plasma reactor. If a seller insists one method is always better, ask why, because neither GIA nor IGI says so.

The properties that define a diamond are identical in both origins.

That is why the question "are lab diamonds real" has a short answer: yes. We cover it in detail, including the words sellers may and may not use, in are lab diamonds real.

Because lab-grown and natural diamonds are the same material, a jeweler's handheld tester will call both "diamond." Telling origin apart takes laboratory equipment. Gem labs look at growth patterns under strong ultraviolet light (HPHT and CVD stones show characteristic shapes), at the trace elements and defects detected by spectroscopy, and at inclusions such as metallic flux. Large labs screen every stone they receive.

Once identified, graded lab-grown stones are typically laser-inscribed on the girdle with the report number and a lab-grown notation, readable under a loupe. That inscription and the report are your proof of origin. Without them, only a lab can tell you for sure.

Most lab-grown diamonds sold today are graded by IGI, which gives them full cut, color and clarity grades on the same scales used for mined stones. GIA changed its approach on 1 October 2025: it now issues a Laboratory-Grown Diamond Quality Assessment that places stones in broad quality groups instead of assigning D-to-Z color and FL-to-I3 clarity grades. GIA has said that reports issued before the change remain valid.

Either way, the report number can be checked on the lab's website, and the measurements on the report should match the stone. The details of reading both are in our GIA and IGI certificates guide.

Lab-grown diamonds cost a fraction of mined diamonds with the same grades, and their prices have fallen fast. One retailer analysis puts the drop in lab-grown retail prices at about 88% since January 2020, with the decline slowing in 2026. Growers keep getting more efficient, so new stones keep getting cheaper.

That is good news at purchase and bad news at resale. Because a new lab-grown stone costs less every year, a used one has little resale value. Buy a lab-grown diamond for the size and look it gives you today, not as a store of value. In our house inventory the gap is easy to see: the Round Lab Diamond Ring 4.15 ct, 14K Yellow Gold is $2,700, while the Round Natural Diamond Ring 4.25 ct, 14K Yellow Gold, with the same E color and VS1 clarity, is $6,000.

Under the FTC Jewelry Guides (16 CFR Part 23):

• A lab-grown diamond must be clearly and conspicuously identified as lab-grown, laboratory-grown, laboratory-created or [manufacturer]-created.
• Words like "real," "genuine" and "natural" may not be used for lab-grown stones.
• A diamond simulant such as cubic zirconia or moissanite must never be called a diamond.

Every lab piece in our catalog is listed as "Lab Diamond" in its title, so the origin is the first thing you read.

Because a lab-grown diamond is diamond, it wears like one. It scores 10 on the Mohs hardness scale, the top of the scale, so daily contact with keys, counters and steering wheels will not scratch it. It does not cloud, yellow or lose its sparkle over the years. What dulls any diamond is a film of lotion, soap and skin oil on the back of the stone, which a soak in warm water with mild soap and a soft brush removes.

Hard is not the same as indestructible. Diamond can chip if a thin edge or point takes a sharp knock at the wrong angle, which is why pear tips, marquise points and princess corners are usually protected by a V-prong or bezel. That risk is identical for lab-grown and mined stones.

The biggest change lab-grown diamonds brought is in high-carat jewelry. Chains, necklaces and bracelets that carry 10, 20 or 30 carats of diamonds used to be out of reach for most buyers. With lab-grown stones they are not. The Round Lab Diamond Necklace 30 ct, 14K White Gold is $8,950 in the house inventory, and the Round Lab Diamond Bracelet 7.49 ct, 10K White Gold is $2,200, both graded E color and VS1.

The same rules apply as for a ring: the origin should be stated, the total carat weight should be in writing, and the stones should look even in color from one end to the other.

1. Pick the shape and size first; lab-grown makes larger stones realistic, so decide what looks right on your hand.
2. Aim for colorless or high near-colorless (D to G). With lab stones the premium for top color is small.
3. Aim for eye-clean clarity: VS2 or better in brilliant shapes, VS1 or better in emerald cuts.
4. For a center stone above about 1 carat, ask for an IGI or GIA report and check the number online.
5. Look at the stone in person, in daylight and under spotlights.
6. Make sure "lab-grown" is written on the receipt, with the metal karat.

Lab-grown stones make up most of the house inventory. The numbers, straight from the catalog:

For engagement rings, start with lab diamond engagement rings, or go straight to a shape: pear or radiant. Everything else is in diamond jewelry.