Electronic gold testing devices work by measuring the decay of electrical current passing through the metal being tested. You rub two spots on the jewelry piece with a clean rubber eraser (think school pencil box). One of the clean spots is clipped to a test board. The second clean spot is touched with a sensor that releases a small drop of non-toxic test gel. Battery current then runs through the metal and into the test unit, which gives you a karat reading on an LCD screen. Tri-Electronics Gold Testers rely upon an environmentally friendly gel cartridge to safely test the karat of gold jewelry and chains. There is no marking or destruction of the pieces that are tested. Testing is fast.
Electronic gold testers offer important advantages over the acid method of testing the karatage of gold. Acid based gold karat testing relies on muriatic acid (that's hydrochloric acid) which has a corrosive effect upon human tissue with potentially irreversible damage to respiratory organs, eyes, skin and intestines. Acid testing of karatage requires rubbing the jewelry against a test stone, which mars the jewelry. Manufacturers of acid based gold test kits sometimes mislabel the acid, leading to expensive mistakes and inaccurate results.
