The term “certified diamonds” refers to polished diamonds that have undergone a quality analysis, based on 4C, by a reputable gemological laboratory such as the GIA (Gemological Institute of America).
Non-certified diamonds are very common in the market and are simply those diamonds that have not undergone formal laboratory grading.
Certified diamonds are not inherently better than non-certified diamonds, but they tend to be higher quality stones because the retailer has chosen them for their documented quality. Many times, certified diamonds are completely natural and have not been treated.
The quality of certified diamonds has been verified, allowing consumers to buy with confidence based on the diamond’s attributes. For small stones or decorative stones, you might consider buying a non-certified diamond. In smaller diamonds, it may be difficult or nearly impossible to see the quality characteristics with the naked eye. However, GIA offers special testing for loose and mounted diamonds in smaller sizes.
Each certified diamond has a unique “certificate”. It is important not to confuse a “Diamond Certificate” with a “Diamond Appraisal”.
Diamond certificate vs. diamond appraisal
There is a significant difference between the two documents. Typically, the diamond seller prepares a diamond appraisal to indicate the estimated value for insurance purposes, while a diamond certificate is an impartial analysis of the quality of the stone prepared by a gemological laboratory.
Sources: Elegir entre diamantes certificados y no certificados (2019)