Abstract: A mounting gauge for measuring the size of a stone mounting including a support assembly having a plurality of individual arms extending from the support assembly. A disk like foot is mounted at the end of each of the arms and is substantially perpendicular to the longitudinal axis of each arm. The feet are successively larger in diameter. The support assembly can be a circular member, a rectangular member, or can be of other shapes. Also, it can include a linear array of body portions pivotally positioned on a post and including a positioning assembly whereby the body portions can be rotated about a post and can be locked in either of two diametrically opposed positions. The individual arms can be made retractable permitting the selection of a single arm for measurement. Gauging bores can also be included for measuring the size of the stone with the diameter of the bores being successively larger and corresponding to the diameter of the disk like feet.