Diamond testers are handy little electronic devices frequently used by jewelers to establish the authenticity of diamonds. If you are in the business of buying, selling, or collecting diamonds, then it’s important to be able to confirm whether that stone is real or not. A diamond tester is generally a portable handheld device, frequently shaped like a pen, suitable for carrying in your pocket. It will typically feature a small needle-like tip. The tip is placed on the stone to be tested, and an audible sound or visual display will denote the authenticity of the diamond.\r