Cut
The cut of a diamond refers to its depth and width proportions as well as the uniformity of its facets. This is the most important diamond characteristic because the angles and finish of a cut diamond determine its ability to reflect light and produce sparkle. Cut is not to be confused with a diamond's shape, such as Asscher, Radiant or Oval.
Color
Color refers to the presence or absence of color in a white (or fancy colored) diamond. Colorless diamonds (D-F) are usually preferred. For some, however, an extremely faint trace of yellow may “warm” the diamond and add to its brilliancy. This hint of color can be subdued or accentuated by the diamond's mounting.
Clarity
Clarity refers to the presence of inclusions (flaws) on or within a diamond. Clarity ranges from IF (Flawless) to I3 (Included). For clarity grades IF to SI (Slightly Included), inclusions are not visible to the naked eye. Diamonds with few inclusions are rarer and more highly valued than those with less clarity.
Carat
A carat is the unit of measurement used to weigh a diamond. It is not to be confused with karat, which measures the purity of gold. The rarity of larger diamonds causes their price to increase exponentially. That is, the cost of a one-carat diamond cannot be calculated by doubling the cost of a half-carat diamond.
Certification
A diamond's certificate serves as proof of its identity and value. The certificate reflects the diamond's exact measurements, clarity, color, and weight. The three primary diamond labs that issue certificates are the Gemological Institute of America (GIA), American Gem Society (AGS), and European Gemological Laboratory (EGL).
Cost
A diamond's cost depends upon the combination of its carat weight, color, cut, and clarity. A one-carat diamond with inclusions may cost less than a .75-carat diamond with a higher clarity value. Before buying a diamond, decide which factors are most important to you and narrow your search accordingly.
