Material: Natural Black Spinel (high temperature resistant material, ideal for wax casting). Origin of ore: China. Priced per 5 gemstones or 10 gemstones. You can select a size. Size: 1.5x2mm, 1.5x3mm, 2x2.5mm, 2x3mm, 2x3.5mm, 2x4mm, 2.5x5mm, 3x4mm, 3x5mm, 3x6mm, 5x7mm.