Jewelers Bulk Lot: Four (4) Boxes PuriTEST Pro Quality Test Stones, Total of 20 Stones &#9989; Professional quality stones for testing scrap jewelry, coins, bullion bars, antiques, art, and any other precious metals items &#9989; Each stone measures 2" x 2" (inches) &#9989; Exquisite new material is durable and will last many uses &#9989; Test gold, silver, platinum, palladium, niobium, or any other precious metals you have acids for &#9989; Will NOT damage the bullion/jewlery you wish to test