Mato&reg; Gemstone Gems Jewelry Tester Diamond Selector Tool with LED Indicators Audio (Black) - 100% brand new and high quality Gemstone tester diamond selector tool. - Easy to use even for a new beginner. - Emit audible sounds to give accurate reading. - Diamond indicator will be shown if the stone is a REAL diamond (Green light). - Metal alert (continuous buzzing sound when user accidentally touches metal rather than stone).