A lab grown diamond is only as trustworthy as the paperwork that comes with it. Certification is what turns a beautiful stone into a verified asset — proof of exactly what you are buying and confirmation that it has been graded to the same standards as any mined diamond. This guide explains what a certificate covers, who issues the ones that matter, and how to verify yours.
A lab grown diamond certificate is an independent grading report — most reliably from GIA or IGI — that documents the stone's 4Cs, its measurements, and its lab grown origin. It should match a laser inscription on the diamond's girdle, and you can confirm it online using the report number. Never buy a lab grown diamond without one; the certificate is your guarantee of quality and authenticity.
What certification actually proves
An independent grading report tells you three things: that the stone is a genuine diamond, that it was created in a lab rather than mined, and precisely how it grades against the 4Cs — cut, color, clarity, and carat weight. Because the assessment is carried out by a third-party laboratory with no stake in the sale, it gives you an objective benchmark to compare stones and prices. Our diamond education hub explains how each of the 4Cs affects a diamond's beauty and value.
Who issues certificates that matter
GIA (Gemological Institute of America)
GIA created the modern 4Cs system and is regarded as the strictest and most consistent laboratory in the world. A GIA report is a gold-standard reference, and GIA grades lab grown diamonds using the same rigorous methodology it applies to mined stones.
IGI (International Gemological Institute)
IGI grades a large share of the world's lab grown diamonds and is widely trusted for them. Its reports are detailed and reliable, and IGI has deep specialist experience with lab grown material specifically. Both GIA and IGI reports are accepted with confidence at Rêve Diamonds.
What a grading report contains
A typical report lists the report number, the diamond's shape and measurements, carat weight, color grade, clarity grade, cut grade (for round brilliants), polish and symmetry, fluorescence, and a clear statement that the stone is laboratory-grown. Many reports also include a plotted diagram of the diamond's characteristics. Reading these together tells you far more than any single grade in isolation.
How to verify your certificate
Verification is simple. First, find the report number laser-inscribed on the diamond's girdle — it is microscopic but matches the certificate. Second, enter that number into the report-check tool on the GIA or IGI website to confirm the details match. If the inscription and the online record agree with the physical stone, your diamond is exactly what it claims to be. This is also why an authentic lab grown diamond is just as 'real' as a mined one — see our explainer on whether lab grown diamonds are chemically the same as natural diamonds.
Why certification protects your money
Certification lets you compare like with like. Two diamonds that look similar can differ substantially in grade and therefore price, and only an independent report reveals that. It also underpins resale and insurance valuations. Whether you are choosing an engagement ring, a diamond pendant, or comparing lab grown value in our lab grown diamond guide, the certificate is what makes the price meaningful.
Frequently asked questions
Do lab grown diamonds come with certificates?
Reputable ones always do. Look for an independent GIA or IGI report; avoid any lab grown diamond sold without third-party certification.
Is IGI or GIA better for lab grown diamonds?
Both are trustworthy. GIA is the strictest overall benchmark, while IGI has extensive specialist experience grading lab grown stones. Either provides a reliable, independent assessment.
Can a certificate be faked?
This is why you verify the report number online and check it against the laser inscription on the stone. Matching all three — stone, inscription, and online record — confirms authenticity.
At Rêve Diamonds, every lab grown diamond is supplied with an independent GIA or IGI certificate and a matching laser inscription, so you always know exactly what you own.
