Accurate Diamond Testing: Professional diamond tester pen can quickly and accurately identify real diamonds from fake ones. Portable and Convenient: Compact design allows you to carry it with you anywhere, perfect for jewelry stores, pawn shops, and gemstone enthusiasts. Easy to Use: Simply turn on the tester and place it on the diamond or gemstone to get a quick and reliable result. Multi-Purpose: Not only can it test diamonds, but also other precious stones like jade, ruby, and sapphire.