Stone Setting Calculator

This calculator turns a stone's diameter and height into the bench-ready dimensions for three common ways of setting it, using ratios drawn from standard jewelry-making practice rather than rigid engineering formulas. For a bezel setting, the wall height is set to about 70% of the stone's height plus the metal thickness (bezels typically wrap two-thirds to three-quarters of the way up a stone so it stays gripped without hiding too much of the crown), and the cup diameter adds clearance equal to twice the metal thickness so the bezel strip can be formed around the stone's girdle. The strip length itself is just the circumference of that cup diameter (π × diameter) plus 1mm for the solder seam overlap. Prong settings need far less metal height — only enough to reach the stone's girdle and curl over the top, modeled here at 50% of stone height — and skip the strip-length calculation entirely since prongs are cut from wire or cast, not formed from strip.

Channel settings sit in between at 60% height, with a slightly tighter cup diameter for a snug fit between two milled walls. Two supporting numbers round it out: seat depth (40% of stone height) tells you how deep to cut the ledge the stone rests on, and bearing width estimates how wide that inner ledge needs to be. Because these are rule-of-thumb ratios, not calibrated stone specs, always dry-fit your actual stone before cutting or soldering — calibrated and natural stones vary enough in proportion that the seat may need hand adjustment.