This premium large quality Gold, Silver, and Platinum testing scratch stone from GTE is the ideal solution for easily authenticating precious metals. Crafted with precision, its 3" by 6" surface and durable rubber backing provide a stable, non-slip platform for getting accurate scratch test results every time. The multi-metal design allows testing of gold, silver, and platinum simultaneously. Simply scratch the jewelry you are testing against the stone, apply a drop of the solution, and watch the results appear! Clean with baking soda and water or GTE Neutralizer before using again. Designed to withstand frequent, long-term use, easy to clean, this reusable stone can be utilized hundreds of times, making it a cost-effective investment. Whether testing jewelry, coins, or other items in a retail or personal collection, professionals and enthusiasts alike will appreciate the convenience and dependability of this premium 3x6 testing stone.