Abstract

A high brilliance step-cut gem stone is formed by cutting natural or man-made gem stone material at a cutting angle of 90° along respective cutting machine indices of 96, 48, 72 and 24 to form a rectangular block and then shaping the rectangular block by cutting the block along respective indices 94, 2, 50, 46, 70, 74, 26 and 22, to define an octagonal prism. The pavilion portion of the stone is formed by cutting a plurality of pavilion facets in stepped increments along each of the indices 94, 2, 50, 46, 70, 74, 26 and 22. A first group of pavilion facets defining the culet is cut at the critical angle of the material and each successive group of facets is cut in successive stepped increments of 6° relative the critical angle, up to the girdle. A plurality of crown facets are also cut in stepped increments along each of the indices 94, 2, 50, 46, 70, 74, 26 and 22, upwardly from the girdle to define a relatively flat table at the top of the stone. In accordance with the present invention, an octagonal step-cut gem stone is provided having a higher brilliance and a wider cone of brilliance than the conventional rectangular or square step cut gem stone.