Lab-grown basics
Lab-Grown Diamonds: What to Know Before You Buy
A lab-grown diamond is diamond: the same carbon crystal as a mined stone, sold with a lab-grown disclosure. Here is how it is made, how it is identified, how it wears and what to expect if you ever sell it.
What is a lab-grown diamond?
It is diamond: carbon atoms in the same cubic crystal lattice as a mined stone, with the same hardness and essentially the same chemical, physical and optical properties. It is not a simulant. Cubic zirconia and moissanite are different materials that imitate diamond.
The US Federal Trade Commission's Jewelry Guides define a diamond as "a mineral consisting essentially of pure carbon crystallized in the isometric system" (16 CFR §23.12). A lab-grown stone meets that definition. The FTC requires disclosure: the seller must call it "laboratory-grown," "laboratory-created" or "[manufacturer]-created." You will see "lab-grown" on the listing, the certificate and the stone itself.
How are lab-grown diamonds made?
Both methods grow new diamond onto a small diamond seed. HPHT (high pressure, high temperature) crystallizes carbon from a molten metal at conditions similar to those deep in the earth. CVD (chemical vapor deposition) deposits carbon from a gas plasma, layer by layer, in a vacuum chamber.
Neither method makes a better diamond on its own; the cut, color and clarity grades decide how the stone looks. The growth method is printed on the GCAL certificate.
Does a lab-grown diamond pass a diamond tester?
Yes. Handheld testers measure how a stone conducts heat, which separates diamond from look-alikes. A lab-grown diamond reads as diamond. Occasionally a combined thermal-and-electrical tester can misread one; if that happens, the girdle inscription and the GCAL certificate settle it.
A tester cannot tell where the diamond formed, and neither can a jeweler's loupe. GIA states that traditional gemological instruments can't separate lab-grown from natural. Telling them apart takes lab equipment, such as spectroscopy and ultraviolet fluorescence imaging, which shows the growth pattern.
How can you tell a diamond is lab-grown?
Read the inscription and check the certificate. The grading lab identifies the stone before it is sold and laser-inscribes the girdle, the thin outer edge. The marks are invisible to the eye and readable under 10x magnification.
Every Arelia diamond is inscribed "GCAL 8X LG" followed by its certificate number, plus the words "LAB GROWN." The GCAL certificate states that the stone is lab-grown, names the growth method and shows the inscription, so the number on the stone can be matched to the certificate and to GCAL's online record. Our guide to setting a loose diamond locally covers the checks to make when it arrives.
Are lab-grown diamonds durable?
Yes. Diamond is 10 on the Mohs hardness scale, the hardest natural mineral, and a lab-grown diamond is the same material. It resists scratching the same way a mined diamond does. Like any diamond, it can chip from a hard knock on a thin edge or point, so a setting that protects the girdle and any points is worth the same care.
Do lab-grown diamonds have resale value?
Low, and uncertain. Lab-grown diamonds have been sold in volume for only a few years, so there is no established resale market and no track record for what a stone will be worth later. Prices have also fallen as production has scaled up. A lab-grown diamond is not an investment: buy it to wear.
What the certificate does guarantee is the grading, not the market price. GCAL's written guarantee covers the accuracy of the grades; see what GCAL 8X certification means for its terms. For current prices by size, see lab-grown diamond prices by carat.
Every Arelia diamond is lab-grown, GCAL 8X graded, D–F color and VVS2 or better, with its certificate and 360° video on the product page.
Shop lab-grown diamondsKeep reading
What Is GCAL 8X Certification?The eight cut criteria behind GCAL 8X, how to read the certificate, the laser inscription and GCAL's guarantee.Read the guide →
GCAL vs. IGI vs. GIA: Which Diamond Report Matters?What each lab's lab-grown report actually includes, GIA's 2025 change, and how to pick.Read the guide →
Lab-Grown Diamond Prices by CaratReal prices by carat band from Arelia's live catalog, and what moves the price within a size.Read the guide →
Frequently asked questions
Are lab-grown diamonds real diamonds?
Yes. The FTC defines a diamond as a mineral of essentially pure carbon crystallized in the isometric system, and lab-grown diamonds meet that definition. The seller must disclose that the stone is lab-grown.
Will a lab-grown diamond pass a diamond tester?
Yes. A handheld tester confirms the material is diamond. It cannot tell lab-grown from natural; that takes lab equipment.
What does LG mean on a diamond inscription?
LG stands for lab-grown. Every Arelia diamond is inscribed "GCAL 8X LG" followed by its certificate number, plus "LAB GROWN". You can read it with a 10x loupe and match the number to the certificate.
Are lab-grown diamonds durable?
Yes. A lab-grown diamond is 10 on the Mohs hardness scale, the same as a mined diamond, and wears the same way in everyday jewelry.
Do lab-grown diamonds have resale value?
Very little. There is no established resale market, and lab-grown prices have fallen as production has grown. Buy one to wear, not as an investment.