2x2 NEW White Pro Gold Test Stone Silver 9k 10k 14k 18k 22k 24k Sterling 999 925 Acid Testing Scratch Tool Tester Scrap Jewelry This specially designed high quality testing white test stone can be washed and used again for hundreds of tests. It is designed specifically for testing and leaves a very visible streak when testing gold, silver, and platinum. It will not damage the pieces you are testing. This stone has a rubber backing and is brand new in the original PuriTEST Box! Better clarity when testing! Faster results! Easy to clean and reuse!