This pocket-sized K & B-style aluminum diamond and stone gauge measures loose gemstones and settings from 0.03 to 4 carats and provides the corresponding millimeter values, ranging from 2 to 11mm. Simply drop stones through the holes to measure their size; an inner revolving gauge measures settings. The gauge is tempered for durability and features a handy birthstone chart on the back.

Accurately measure the size of diamonds and gemstones with a K & B-Style Diamond and Stone Gauge. This handy tool features a series of calibrated holes that correspond to standard millimeter and point sizes. Simply slide your stone through the holes until you find the closest fit to determine its size.