GIA Diamond Cut Classifications
A diamond’s proportions determine how light performs when it enters the diamond. If light enters through the crown and goes out through the pavilion, the diamond will look dark and unattractive. Diamonds with different proportions and good polish make better use of the light, and will be bright, colorful, and scintillating. LEARN MORE from the Gemological Institute of America
- brilliant cuts
- step cuts
- mixed cuts
We'll start with brilliant cut diamonds and move through the other cuts step-by-step.
Brilliant Cut Diamonds
Brilliant cut diamonds have facets that are shaped like triangles and kites. The facets radiate outwards and are positioned so that the light coming through them interplays to enhance the diamond's brilliance, or sparkle.
Round is the most popular diamond shape, and the round brilliant cut is probably the most popular version of that cut. Today's round brilliant diamond has a total of fifty-eight facets, but you'll see varying facet numbers in vintage brilliant cut diamonds.
Another popular brilliant cut is the princess cut diamond, a square gemstone.
Step Cut Diamonds
A step cut diamond has sloping, four-sided facets that are cut below the table and run parallel to the diamond's girdle.
Step cut diamonds have fewer facets than brilliant cut diamonds. The baguettes set on each side of the center diamond in this engagement ring are examples of step cut diamonds.
Emerald cuts are step cuts with their corners clipped off. Emerald cuts are usually rectangular, although their proportions can differ significantly, from very narrow rectangles to squares. Emerald cut diamonds tend to have more facets than baguette diamonds.
The Asscher cut is a related, vintage cut that's emerging as a modern favorite. You'll hear more about Asscher cut diamonds on page 3.
Step Cuts and Flaws
One caution, the open appearance of some step cut diamonds can make large inclusions, internal flaws, more obvious in the set stone.
Mixed Diamond Cuts
Mixed cuts include faceting elements from both the brilliant and step cut techniques, either side by side or in different areas of the gemstone. Mixed cuts are frequently used for colored gemstones.
Old Mine Cut:A square, but with gently rounded corners and brilliant-style facets. The crown is typically high, the table is small, and the culet is large enough to be visible through the top of the stone.
Old European Cut: A diamond cut that is much like the old mine cut, but round in shape.
Cushion Cut: Another diamond cut that resembles the old mine cut, but the gemstone is more of a rectangle.
Rose Cut: A vintage diamond cutting style, with brilliant-type facets arranged in groups that make the gemstone resemble an opening rosebud.
Asscher Cut: Developed early in the twentieth century and popular again today. This diamond cut resembles an emerald cut, but is square, with wide step facets and deeply clipped corners that make the diamond look like an octagon. The Asscher cut produces more fire than you see in a typical step cut diamond.