Are bezel settings less sparkly?

A well-cut diamond gets most of its brightness from light entering the top through the table and crown, bouncing internally and returning back out the top to the eye. A smaller share of light enters from the sides through the pavilion and contributes to fire and side flash. A full bezel blocks the side light path completely, so the stone loses roughly 10 to 15 percent of total light return depending on the cut. Most of that loss is fire from the sides, not central brightness, so the everyday read stays close to a prong-set stone.

The bezel penalty is largest on stones that already struggle for brightness: poor cut grades, very deep diamonds that trap light inside, and step cuts like emerald and asscher that rely on flashes through the pavilion rather than scintillation from the top. On an excellent or ideal-cut round, oval or cushion brilliant the loss is barely visible to the eye. If you want both bezel security and maximum brightness, push the budget toward a higher cut grade rather than a higher colour or clarity, since cut quality compensates for the rim more than the other Cs do.