This is a 10 mm yttrium aluminum garnet (YAG) cut in a square brilliant pattern called the Primus cut. This gem scored 97 points and won first place in the faceted gemstone category in the 1998 Castro Valley Mineral and Gem Society annual show. In faceting competitions, synthetic gem materials like YAG are often preferred. That's because natural materials often contain imperfections such as included crystals or flaws that make it difficult to obtain a perfect polish. The extreme purity of manmade materials like YAG eliminate that problem. It took over thirty hours to complete the faceting of this particular gem. (Another award winning gemstone)