There are many diamond grading labs in operation, many of which produce their own grading reports. Different labs have different grading standards, and some labs will be more lenient with their standards than others. Mondera sells only only GIA- or AGS-certified diamonds, as these labs have consistently demonstrated their commitment to standards that are high as Mondera's. If you do elect to buy a diamond elsewhere, always ask for credentials of the certifying lab.

Shopping for certified diamonds allows you to make an informed choice about your selections, and to comparison shop. You can compare one diamond with a particular weight and quality with other diamonds of similar weight and quality to determine which is the better value.

A quick rule of thumb: If a jewelry store offers to sell you a diamond without a certificate, keep in mind that it means you are buying the diamond based only on the salesperson's claim about its quality, and that a trained gemologist or even other jewelers may disagree with the salesperson's assessment.