Facet

Facets are the flat, polished planes that give a cut gemstone its shape and sparkle. Each one sits at a calculated angle relative to the others. Get the angles wrong and light leaks out the bottom instead of bouncing back to your eye. Get them right and the stone looks alive. A standard round brilliant diamond has 57 or 58 facets, split across five named zones. The table is the flat top. The crown sits above the girdle (the stone's widest edge). The pavilion drops below the girdle toward the culet, that tiny point or flat facet at the bottom. Facet counts vary by shape. A round brilliant runs 57-58. An emerald cut might have 50-58 depending on the cutter. A princess cut lands around 50-58. An oval brilliant typically matches round counts. The purpose of all those surfaces is optical control. Crown facets catch light from above. Pavilion facets reflect it back up through the table. That interplay creates brilliance (white light return), fire (rainbow flashes), and scintillation (sparkle when the stone moves). Faceting quality matters more than most buyers realize. I've seen two 1-carat rounds with identical color and clarity grades where one looked dull and the other looked electric. The difference was cut. Misaligned facets, an off-center table, or a pavilion that's too deep or shallow kills performance regardless of what the certificate says. Cutters work on a faceting machine with the stone mounted in a dop, grinding each facet on a spinning lap wheel. Hand faceting still happens for custom work. Production stones go through automated systems. When you're evaluating a stone under a loupe, look at facet meet points. They should be crisp, symmetrical, and aligned. Wavy girdle lines or uneven star facets are red flags.