Diamond Grades Explained

A diamond cut shallow will "leak" light, reducing the brilliance. More weight is retained from the diamond rough, but at a sacrifice of brilliance and beauty.

A diamond cut deep will also "leak" light, again reducing brilliance. More weight can be retained from the diamond rough, but again at a sacrifice of beauty.

Every diamond belongs to a weight grouping - a range where the price per carat for each Color and Clarity combination is listed.

The main reason for pricing shifts is rarity in nature, but current market conditions play a very important role too. Certain sizes and shapes fall in and out of demand depending on what is fashionable or considered affordable, so some weight groupings command a higher price per carat than their rarity alone would suggest.

For example, a diamond in the 1 carat classification (1.00-1.49ct) almost always commands a noticeably higher price per carat than the light 1 carat classification (0.90-0.99ct), even though the difference in size is small.

Because the 1 carat mark carries such weight in buyers' minds, cutters will sometimes retain extra rough material to reach that "magical" size and price bracket - at the cost of the stone's overall brilliance.

Every diamond quality factor involves trade-offs. It is worth choosing the combination that suits your taste from someone knowledgeable and trustworthy.

All diamonds are color graded by a gemologist against a master set from the GIA, from the side, face-down, under controlled daylight-equivalent lighting against a white background.

D-F grades represent the finest and brightest colorless diamonds, prized for both beauty and rarity. G-H grades offer very white, bright stones that are difficult to distinguish from D-F once mounted, at a lower price.

I-J still face up white but are slightly less bright to a trained eye. K-L show a slight tint most people can notice; M and below show visible color face-up.

Each grade shifts value by roughly 10-15 percent through M, changing again for Fancy color diamonds by hue and saturation. Color and Cut are the two factors that influence a diamond's beauty the most - many buyers balance a higher color grade against a lower clarity grade to suit their taste and budget.

Flawless (FL) - a skilled observer under favorable lighting can see no inclusions at ten-power magnification with a binocular microscope or a 10x loupe. Minor features like small extra facets near the girdle are permitted.

Internally Flawless (IF) - no internal characteristics under the same conditions as FL, but with minor surface blemishes that do not penetrate the stone.

VVS1 & VVS2 (Very, Very Slightly Included) - inclusions so small they are difficult even for a skilled gemologist to find at 10x magnification.

VS1 & VS2 (Very Slightly Included) - small inclusions that can be difficult to observe at 10x, rarely visible to the unaided eye except in larger stones or Emerald cuts.

SI1 & SI2 (Slightly Included) - inclusions usually obvious to a gemologist at 10x, and occasionally visible without magnification in larger or Emerald cut stones.

I1, I2 & I3 (Included) - medium to large inclusions, usually obvious to the unaided eye; I1 inclusions sit toward the edge while I2 and I3 are more central or numerous.