A lab grown diamond is a real diamond. Not a diamond "alternative." Not an imitation. Not a clever marketing term for something lesser. A diamond — grown inside a laboratory rather than pulled from the earth, but chemically, physically, and optically identical to anything you'd find in a mined stone.
If that's news to you, good. That's exactly why this page exists.
The Simple Definition
A lab grown diamond is a gemstone made entirely of carbon atoms arranged in the same crystal lattice structure as a mined diamond. Both form under conditions of extreme heat and pressure — one over billions of years deep in the Earth's mantle, the other over a matter of weeks inside a controlled growth chamber. The conditions are replicated; the result is the same.
That sameness isn't a marketing claim. It's measurable science:
- Hardness: 10/10 on the Mohs scale — the hardest material on Earth, identical to mined diamonds
- Refractive index: 2.417–2.419, which is what gives diamonds their signature brilliance and fire
- Chemical composition: Pure carbon (C), bonded in a cubic crystal lattice — the precise definition of a diamond
- Density: 3.51–3.53 g/cm³ — same as a mined stone
- Thermal conductivity: Among the highest of any material, which is why diamonds feel cold to the touch
A professional jeweler looking through a loupe sees a diamond. A standard diamond tester reads a diamond. A spectroscope shows the diamond spectrum. The only instruments that can detect a difference are specialized gemological devices that look for microscopic growth patterns — not visual differences, not quality differences, just origin signatures.
What a Lab Grown Diamond Is NOT
This is where most of the confusion in the market lives, so let's clear it up plainly.
Lab grown diamonds are not cubic zirconia. CZ is made from zirconium oxide — an entirely different material. It's softer, has a different refractive index, clouds over time, and fails a standard diamond tester immediately. Comparing a lab grown diamond to CZ is like comparing a river pearl to a plastic bead.
Lab grown diamonds are not moissanite. Moissanite is silicon carbide — beautiful in its own right, but a completely different stone with different chemistry, different hardness (9.25 vs. 10), and a slightly different optical character. It is not a diamond.
Lab grown diamonds are not "synthetic" in any diminishing sense. Gemologists use the word "synthetic" to simply mean "not formed in the Earth" — a technical classification of origin, not quality. The U.S. Federal Trade Commission made this official in 2018, removing the word "natural" from its legal definition of a diamond entirely. Under federal law, a lab grown diamond that meets the carbon-crystal-lattice criteria is a diamond.
What Are They Actually Made Of?
Every diamond — mined or lab grown — is made of pure carbon. What makes a diamond a diamond isn't where the carbon came from. It's how the carbon atoms are arranged.
When carbon is forced into a specific tetrahedral crystal lattice structure under extreme heat and pressure, it becomes diamond. Under slightly different conditions, the same carbon becomes graphite — pencil lead. The arrangement is everything.
In nature, that arrangement happens roughly 100 miles below the Earth's surface: temperatures exceeding 2,000°F, pressures over 700,000 pounds per square inch, and a timeline measured in millions to billions of years. Volcanic activity eventually pushes those crystals toward the surface.
In a lab, scientists recreate those same essential conditions — the same carbon source, the same temperature and pressure parameters — and compress the timeline to weeks. The carbon atoms behave the same way. The crystal structure that forms is the same structure. The diamond that results is the same diamond.
How Are They Made? (The Short Version)
There are two primary methods used to grow diamonds in a laboratory. Both start with a tiny diamond "seed" — a thin slice of existing diamond — and both produce a genuine diamond crystal.
HPHT (High Pressure High Temperature) mimics the Earth's mantle. The seed is surrounded by carbon material and subjected to temperatures around 1,400–1,600°C and pressures of roughly 50,000–60,000 atmospheres. Carbon dissolves and crystallizes around the seed, growing layer by layer over 2–4 weeks.
CVD (Chemical Vapor Deposition) takes a different route. The seed goes into a vacuum chamber filled with a hydrogen-carbon gas mixture. Microwave energy ionizes the gas into a plasma, and carbon atoms rain down onto the seed, building up a crystal layer by layer. CVD runs at lower temperatures (~900–1,200°C) and is particularly well-suited for producing high-clarity, high-color stones.
For a full deep-dive on both processes, see our guide: How Are Lab Grown Diamonds Made.
Are Lab Grown Diamonds Graded?
Yes — exactly the same way mined diamonds are. Lab grown diamonds are certified by the same independent gemological laboratories: the IGI (International Gemological Institute) and the GIA (Gemological Institute of America), using the same Four Cs framework:
| Grade | What It Measures |
|---|---|
| Cut | How well the diamond is faceted to interact with light |
| Color | Graded D (colorless) to Z (light yellow/brown) |
| Clarity | Presence or absence of internal inclusions |
| Carat | The weight of the stone |
When you purchase a lab grown diamond with an IGI or GIA certificate, you're getting the same objective, third-party quality assessment that applies to any mined diamond. A VS1, G-color, Ideal-cut 1.5ct lab grown diamond is graded on identical terms to a mined stone with the same characteristics.
Note: In 2025, GIA updated its lab grown grading system to use broader "Premium" and "Standard" tiers for color and clarity, rather than individual letter grades. IGI continues to apply full 4Cs individual grades to lab grown diamonds. When buying, it's worth checking which lab issued your certificate. For a full breakdown, see our Lab Grown vs. Natural Diamond guide.
One Surprising Bonus: Lab Grown Diamonds Are Often Purer
Here's something the traditional diamond industry doesn't love to advertise: a large percentage of naturally mined diamonds contain trace nitrogen impurities absorbed over billions of years underground. These impurities contribute to the yellow or brown tinting in lower color grades and are characteristic of what's called a "Type Ia" diamond — the most common type, representing about 98% of all mined stones.
Lab grown diamonds — particularly those produced via CVD — frequently achieve Type IIa classification: the chemically purest form of diamond, with little to no measurable nitrogen. Only about 1–2% of naturally mined diamonds are Type IIa. Many lab grown diamonds achieve it routinely.
In a real sense, the average lab grown diamond is more chemically perfect than the average mined diamond. That's not spin — it's the natural result of a controlled growth environment versus billions of years of geological chance.
So Why Does This All Matter?
Because once you understand what a lab grown diamond actually is, the value proposition becomes obvious.
You're not compromising. You're not choosing the "budget version." You're choosing the same stone — formed through the same process, graded by the same standards, with the same physical properties — at a price that reflects a more efficient supply chain rather than billions of years of geology and a global extraction industry.
At LabGrownDiamonds.com, our position has always been simple: a diamond is a diamond. The brilliance is real. The hardness is real. The certificate is real. The only thing that isn't? The inflated price tag.
Ready to see them for yourself? Explore our loose lab grown diamonds — or learn more about how they're made, whether they're real, and how they compare to mined stones.
