925 Silver Lab FIRE OPAL CZ Tanzanite Ring Size 8 Japan Kyocera Lab Created Opal, the finest lab opal made in the world. Lab created Tanzanite. Metal : 925 Solid Sterling Silver, rhodium plated to ensure durability. The triangle shape CZ purple/blue Tanzanite dimension : 7mm x6mm Front Width : 5/8" Tapering to the back : 1/8"