What are lab-grown diamonds? A simple guide
A lab-grown diamond is a real diamond grown in a laboratory instead of mined from the ground. It has the same carbon crystal structure, the same hardness, and the same sparkle as a mined diamond. Grading labs certify lab-grown diamonds on the same 4Cs used for mined stones. The only real difference is origin, and that difference is why a lab-grown diamond usually costs far less per carat.
This guide explains what a lab-grown diamond actually is, how it is made, how it is graded, and how it compares to a mined diamond. If you are shopping for an engagement ring and want to understand what you are buying before you spend, start here.
Are lab-grown diamonds real diamonds?
Yes. A lab-grown diamond is a real diamond. It is made of pure crystallized carbon in the same cubic crystal structure as a mined diamond, so it has the same hardness of 10 on the Mohs scale and the same optical properties. In 2018 the US Federal Trade Commission updated its Jewelry Guides and removed the word “natural” from its definition of a diamond, which confirmed that a lab-grown stone is a diamond, not an imitation.
A lab-grown diamond is a real diamond that was grown in a lab. It is not a mined diamond. Both are true at the same time.
The word “real” is where people get stuck. What a lab-grown diamond is not is a simulant. A cubic zirconia or a moissanite looks like a diamond but is a different material with different properties. A lab-grown diamond is the same material as a mined one, tested and graded the same way. Hand someone a mined diamond and a lab-grown diamond of the same grade, and they will not tell them apart by eye.
How are lab-grown diamonds made?
Lab-grown diamonds are made by two methods: high pressure high temperature (HPHT) and chemical vapor deposition (CVD). Both start with a tiny diamond seed and add carbon to it atom by atom until a rough diamond forms. That rough is then cut and polished the same way a mined rough is. The growth stage takes roughly a few weeks, not the millions of years a mined diamond needs underground.
- HPHT recreates the heat and pressure found deep in the earth. A seed sits with a carbon source and a metal flux, then extreme pressure and heat crystallize carbon onto the seed. It is the older method and is also used to improve the color of some finished stones.
- CVD grows a diamond from carbon-rich gas. A seed sits in a vacuum chamber, gas such as methane fills it, and energy breaks the gas apart so carbon settles onto the seed layer by layer. CVD gives growers tight control, which is why it is common for gem-quality stones.
Both methods produce a genuine diamond. A certified CVD stone and a certified HPHT stone of the same grade are equal in quality, so the growth method does not make one more real than the other.
How lab-grown diamonds are graded: the 4Cs
Lab-grown diamonds are graded on the 4Cs, the same four factors used for mined diamonds: cut, color, clarity, and carat. A grading lab measures each one and prints the result on a certificate tied to the individual stone. When you buy from a store that names the lab and shows the report, you can check every grade yourself.
- Cut describes how well the diamond returns light and has the biggest effect on sparkle, so it is worth prioritizing.
- Color runs from D (colorless) down as a faint tint appears. Near-colorless grades in the G to J range often look white once set and cost less than D to F.
- Clarity measures inclusions. Eye-clean grades such as VS1 and VS2 show nothing to the naked eye, the practical target for most buyers.
- Carat is the weight of the stone. Two diamonds of the same carat can look different sizes depending on the cut.
Two labs certify most lab-grown diamonds sold in the US: the International Gemological Institute and the Gemological Institute of America, both of which grade lab-grown stones on the same scales they use for mined diamonds. You can read how each grade is measured on the GIA 4Cs pages. A certificate from either lab, with a report number you can look up, is the proof that the grades on a product page are real.
Lab-grown vs mined diamonds
Lab-grown and mined diamonds are the same material with the same look and the same grading. The differences come down to origin and price. A lab-grown diamond is grown in weeks in a controlled facility, so supply is not limited by mining, and it typically costs much less per carat. Buyers often use that gap to choose a larger or higher-grade stone for the same budget.
| Factor | Lab-grown diamond | Mined diamond |
|---|---|---|
| Material | Crystallized carbon | Crystallized carbon |
| Hardness (Mohs) | 10 | 10 |
| Graded on the 4Cs | Yes | Yes |
| Origin | Grown in a lab in weeks | Formed underground over geological time |
| Typical price per carat | Lower | Higher |
Wait, why does the price gap exist if the stones are identical? Because a mined diamond carries the cost and scarcity of mining, while a lab-grown stone can be produced on demand. Same material, different supply. One honest note: lab-grown diamonds hold little resale value today, so choose one for its beauty and the value it buys now, not as something to sell later.
The bottom line
A lab-grown diamond is a genuine diamond, identical to a mined one to look at and to wear, graded on the same 4Cs and backed by the same certification. For most shoppers that means the same certified quality for less money, which often buys a bigger or cleaner stone than mined at the same price.
At Candor Diamonds, every diamond we sell is lab-grown and IGI or GIA certified, with the report reachable so you can check the grades yourself. Each stone is backed by a lifetime warranty, free insured shipping, and 30-day returns. Browse certified stones by shape and carat weight, and you will see exactly what your budget buys before you commit.
Frequently asked questions
Are lab-grown diamonds fake?
No. A lab-grown diamond is a real diamond made of the same crystallized carbon as a mined one, with the same hardness and sparkle. “Fake” diamonds are simulants such as cubic zirconia or moissanite, which are different materials.
Do lab-grown diamonds pass a diamond tester?
Yes. Standard diamond testers check how a stone conducts heat, and because a lab-grown diamond is chemically the same as a mined diamond, it passes as a diamond.
Do lab-grown diamonds get cloudy or lose sparkle over time?
No. A lab-grown diamond does not cloud or fade. It is a 10 on the Mohs hardness scale, so it resists scratching and keeps its sparkle with normal cleaning.
Which is better, CVD or HPHT?
Neither is better as a finished stone. Both produce genuine diamonds, and a certified CVD and a certified HPHT diamond of the same grade are equal. What matters is the grade on the certificate.