Lab-Grown Diamonds: A Plain-English Guide

Lab grown diamonds are real diamonds: crystals of carbon with the same atomic structure, hardness and optical properties as diamonds mined from the earth. What sets them apart is where they come from. Instead of forming deep underground over geological time, they are grown in specialized facilities in a matter of weeks. This page explains how they are made, how they differ from simulants and mined stones, and what to check before you buy lab-grown diamond jewelry.

How lab-grown diamonds are made

There are two main production methods. HPHT (high pressure, high temperature) recreates the crushing pressure and heat found deep in the earth to crystallize carbon around a small diamond seed. CVD (chemical vapor deposition) places diamond seed plates in a chamber filled with carbon-rich gas, which is energized so carbon atoms settle onto the seeds layer by layer. Both methods produce real diamond, and some stones receive additional treatment after growth to improve color. A grading report will usually tell you which method was used and whether any post-growth treatment was detected.

Lab-grown diamonds vs. simulants

A lab-grown diamond is not the same thing as cubic zirconia or moissanite. Those are different materials that imitate the look of a diamond. If a listing calls a stone a “diamond alternative” or “simulated diamond,” it is not a lab-grown diamond.

How they are labeled in the US

The Federal Trade Commission’s Jewelry Guides treat a diamond as a diamond whether it was mined or created in a lab, but they require sellers to disclose a lab origin clearly, with terms such as “laboratory-grown,” “laboratory-created” or the producer’s name followed by “-created.” If the origin is not stated clearly, ask before you buy.

Grading reports and the 4Cs

Many lab-grown diamonds are sold with a report from a gemological laboratory such as IGI or GIA. Reports describe cut, color, clarity and carat weight, list measurements and usually carry a report number that you can look up on the lab’s website. Some stones also have that number laser-inscribed on the girdle. Our lab-grown diamond buying guides explain how to read a report line by line.

What to weigh before buying

• Price: lab-grown diamonds are often priced below mined diamonds of similar size and quality, but prices vary widely by retailer and change over time.
• Resale: resale value for lab-grown diamonds is generally limited, so buy for enjoyment rather than as an investment.
• Policies: compare return windows, warranties, resizing and shipping insurance, which can matter as much as the stone itself.

Explore by jewelry type

Start with lab grown diamond engagement rings, earrings, necklaces, tennis bracelets or wedding bands. Shopping for someone else? See our lab-grown diamond jewelry gift guides.

How we write these guides

Our guides draw on published grading standards, retailer product information and FTC guidance. We do not claim hands-on testing unless a guide says so, and we never invent prices, ratings or reviews.