Brilliant:
This technique creates triangular-shaped facets that face outwards from the center of the diamond. Most often the term is used to refer to round brilliant cuts, the most popular cut.
Rose:
An antique style cut with trangular facets coming to a point (no table) and a flat bottom (no pavilion).
Step:
A cut with rows of long, rectangular facets resembling a staircase.
European:
Dating back to the 1800s, this cut possesses a circular girdle with a high crown, small table, and a large, flat culet. With 58 facets, it is the predecessor of today’s modern round brilliant cut.
Old Miner:
A cut dating back to the Victorian era that features a squarish girdle with gently rounded corners. Old mine cut diamonds have a high crown, a small table, and a large, flat culet.
Single:
A round cut with only 17 or 18 facets, as opposed to the brilliant's 57 or 58 facets, and is common for "melee" diamonds.
Flat:
An unfaceted slice, disc, or similar shape.
Grooved:
Certain shapes, particularly the princess cut, can be grooved on the edges to allow them to be "invisibly" set together (without prongs or metal in between).