Most diamonds on the market have 57 or 58 facets. A standard round diamond usually has 57; sometimes the culet is polished flat to protect it from chipping, which adds one small facet and makes 58. Beyond the traditional cut, some sellers now offer diamonds with 88, 89, 101, 108 or 121 facets, which look more novel and distinctive.
Facets versus proportions
More facets do help a diamond reflect light, but more is not always better. A good cut depends on fine polish and precise geometry, and adding facets without regard to whether the cut is sound will not make a diamond brilliant.
What matters more for a diamond's fire is the proportions of the cut. Every diamond cut is the result of precise calculation by cutters working from the principles of optics, and adding or removing facets at will throws those proportions off.
So when you buy a diamond, look past the facet count to the overall proportions and how the stone actually looks. For the most fire, choose an Excellent (EX) cut grade where you can.
