Verify the authenticity of gold and silver with this 10K, 14K, 18K & Silver Testing Solution Kit with Scratch Stone. Each 12g bottle comes in a sturdy, leak-resistant container with an internal baffle for safe, precise application. The included 2" x 1.5" x 1/4" dark testing stone is reusable and trusted by jewelers for testing gold, silver, and platinum. For gold, scratch the item on the stone, apply a drop of solution, and check if the mark remains to confirm karat level. For silver, observe the color change: 999 = Bright Red, 925 = Dark Red, 800 = Brown, 500 or less = Green. Ideal for jewelers, appraisers, pawn shops, and collectors who need a fast, accurate, and reliable way to test precious metals.