Proportionscope for Diamond Cut Specs | Using a Proportionscope

A proportionscope is used to determine angles and percentages of the stone.

A proportionscope, first designed and manufactured by GIA in 1967, is an instrument that casts a silhouetted image of the diamond It allows us to check the proportions of the stone in question. This is a handy gemological tool to include in one’s lab, but not an absolute necessity to start off with.