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How to Know if a Lab Diamond Certificate is Legitimate
Some online listings claim that their lab diamonds are “certified” — but what does that really mean?
Not all certifications are equal, there are many misleading or outright fake certificates in circulation, especially on large online marketplaces that unfortunately don’t enforce listing accuracy as they should to protect the buyer.
Here’s how to tell if the certification is trustworthy:
✅ Legitimate Diamond Grading Labs
These institutions are internationally recognized and use strict grading standards. A lab diamond with certification from one of these labs is considered trustworthy:
- IGI – International Gemological Institute
The most common and reliable certification for lab-created diamonds. - GIA – Gemological Institute of America
Known for grading natural diamonds, but also offers limited lab diamond reports. - GCAL – Gem Certification and Assurance Lab
Provides highly detailed reports, including light performance.
You can typically verify the report directly on the lab’s website using a report number or QR code.
❌ Non-Legitimate or Misleading “Certs” to Watch Out For
There are many unofficial or fake “labs” that issue documents to make a gemstone appear certified — but they don’t follow strict grading standards, and the certificates often contain misspellings, vague grading, or poor formatting.
Examples of questionable or misleading names include:
- Authentic Gem Laboratory (AGL) – Not to be confused with any similarly named real lab. These certificates often contain errors and vague, overly positive grading.
- USA Certified Labs, Diamond Test Certificate, or Professional Gem Lab (PGL) – These are not recognized or verifiable.
- Certificates that lack any serial/report number, or offer no way to verify online.
If a certificate looks generic, lacks lab contact info, or seems too vague, it’s best to assume it’s not reliable and you should question this to the seller prior to purchasing.
— if the marketplace has feedback, check it out! Often times if a seller has a high negative feedback or low stars those buyers will explain why and it might be a red flag to pay attention to.
— if it sounds too good to be true, it probably is! You won’t find a lab diamond IF 3ct Radiant cut for $40, we promise!
🔎 Tips to Verify a Certificate
- Google the lab name – Does it have a real website and reputation? (We have seen several use the same abbreviations as legitimate labs, so make sure you have the full lab name and not just the abbreviation of it! Ex: AGL is NOT Authetic Gem Laboratory, it is however American Gemological Laboratories).
- Look up the report number – Legit labs like IGI and GIA have online verification tools.
- Examine the certificate quality – Misspellings, blurry logos, or overly flashy formatting are red flags.
- Ask the seller for a link to the lab’s verification page.
Still Unsure? We’re Happy to Help
We’re here to protect your investment and peace of mind. If you’re ever uncertain about a listing or a certificate, feel free to Contact Us. Our GIA graduate gemologist can help review it and confirm whether we think it’s legitimate or if it might be better to pass up that “great deal”.