Round-Cut

The round is the most-cut shape, and evenness is why: faceted as a brilliant, its facets radiate from the center, so light returns the same as the ring turns. No ratio to weigh, no orientation to choose — depth is what is left to judge. Look through the table: a flat, glassy patch means the pavilion was cut too shallow and light is slipping through.

Cabochon rounds sit here too. Standard millimeter sizes, natural and lab-grown, dropping into any seat cut for them, our ring builder included.