Description: 【Special Function】: This Gold Testing Tool is designed to detect the gold content in items, suitable for testing 10k, 14k, 18k, 22k, and gold. It's an essential tool for jewelry enthusiasts to verify the authenticity of gold. 【Testing Method】: The Jewelry Gold Tester works by applying a drop of test solution onto the stone. Real gold will leave a mark on the stone while fake gold will dissolve or oxidize into blue color. 【Easy to Use】: The Jewelry Tester is very convenient to use as you can determine the authenticity of your jewelry based on color changes after applying the test solution. 【Wide Application】: The Gold Testing Stone is practical for testing all types of jewelry pieces. ideal for testing jewelry, antique gold, collectibles, etc. 【Product Details】: Made from stone mineral that's finely polished yet extremely hard; Product size is 75*40*5mm. Specification: Material: Stone Size Chart:7.5cmx4cmx0.5cm/2.95inchx1.57inchx0.20inch Package Includes: 1 Gold Testing Stone Note: Please allow slightly errors due to manual measurement and different monitors.