Diamond certification is essential when you’re buying a diamond and is different from a jeweler’s appraisal, although the certification is part of any appraisal. Diamond certification is the written proof of a diamond’s attributes. Without it, you have no assurance that the diamond you are buying is of the quality you’re paying for. With it, you know the precise grading for each of the 4Cs – color, cut, clarity and carat weight, and, therefore, the diamond value.

Certification gives you the information you need to assess a diamond’s value compared to other diamonds. Diamond certificates are issued by independent gemological laboratories, not your jeweler. There are several grading laboratories, the most prominent being: the International Gemological Institute (IGI); the Gemological Institute of America (GIA); the American Gem Society (AGS); the European Gemological Laboratories (EGL) and GemEx Systems.

When you buy a diamond, be sure to question the sales associate first about the characteristics or attributes of the stone. Ask to see the diamond certification that will accompany the diamond when you purchase it. If you do some comparison shopping, you will note that the quality of the diamonds each jeweler carries varies depending on the store.

A diamond certification will also give you indicators about other diamond qualities, such as fire, brilliance and scintillation, also called Return of Light. These qualities refer to how light is refracted back to the viewer when held stationary or when in motion.

Carats

Many people equate the term carat with the size of a diamond, and as carat size increases, so will the carat weight. So ¾ of a carat is also 75 points. The heavier in carat weight a diamond is, the rarer it becomes. Prices of diamond increase exponentially with the weight of the diamond, so a one-carat diamond will cost much more than two ½-carat diamonds, given that other qualities, such as color and clarity, are equal.

The cutting of a diamond can impact the size of it, so depending on how their cut, two one-carat diamonds can look unequal. If a stone is cut flatter, then it will appear bigger, while a deeper cut stone will be smaller, but may have more brilliance and scintillation. A smaller diamond can always be enhanced with baguettes, trillians or smaller same-shape stones on either size.