When purchasing certified diamonds it is important to understand the diamond grading criteria used by the laboratories performing the certification. Diamond grading covers numerous aspects of each individual diamond's qualities, but there are four grades which are critical to understand:
- Diamond Cut
- Diamond Clarity
- Diamond Color
- Diamond Carat weight
There are additional ratings and measurements noted on a diamond certificate, but they generally fall under one of these four categories (the "Four Cs"). For example, measurements such as "depth" and "table" are part of the description of the diamond's cut.
"Cut" is used in two different ways in Diamond dictionary. First, it's used to describe the shape of a diamond: emerald cut, heart cut, oval cut... Second, "diamond cut" is used is to describe the reflective qualities of a diamond to determine how well the diamond was cut.
There are 5 grades of diamond cut
- Ideal Cut
- Very Good
- Fair & Poor
Most diamonds have tiny imperfections called inclusions. The visibility, number and size of these inclusions determine what is called the clarity of a diamond, less inclusions means better clarity.
There are 5 grades of diamond clarity
- F (Flawless) - No internal or external flaws
- IF (Internally Flawless) - no internal flaws, but some surface flaws
- VVS1-VVS2 - Very Very Slightly Included 1 and 2
- SI1-SI2 - Slightly Included 1 and 2
- I1-I2-I3 - Included 1, 2, and 3
Colorless diamonds are the most desirable since they allow the most refraction of light (sparkle). Color is a result of the composition of the diamond, and it never changes over time. Color is the most second important characteristic of diamond.
A carat is the unit of weight by which a diamond is measured. One carat is equal to 200 milligrams, or 0.2 grams. Large diamonds have a greater cost per carat and the price of a diamond rises exponentionaly to its size.
The diamond certificate, which is sometimes called a grading report, is a complete evaluation of your diamond and those certificates from respected lavoratories have been performed by a qualified professional with the help of special gemological instruments. Each stone bears its own recognizable and individual characteristics, which is listed on the certificate.