Features: 1. Accurate Gold Verification – This touchstone is designed to reliably test the gold content in jewelry, coins, and other precious metal items. 2. Easy Acid Testing – Apply a drop of testing acid onto the stone; real gold remains unchanged, while fake gold will dissolve or oxidize, turning blue. 3. Wide Compatibility – The solution effectively tests a variety of metals, including 10K, 14K, 18K, 22–24K gold, silver, and platinum. 4. Clear Color Reaction – The acid changes color based on the purity of the metal, making it simple to interpret results. 5. Portable & Practical – Ideal for testing jewelry, coins, antiques, and collectibles, offering a convenient and professional-grade detection tool. Product Details: This large-size touchstone provides a dependable method for verifying the authenticity and purity of gold, silver, and platinum items. The testing process is straightforward: apply a drop of acid to the stone and observe the reaction—genuine precious metals remain stable, while non-authentic materials show visible changes. Suitable for use with jewelry, coins, vintage collectibles, and more, it delivers quick and clear results for both personal and professional use. Specifications: - Material: Durable touchstone with acid-testing compatibility - Testing Range: 10K, 14K, 18K, 22–24K gold, silver, and platinum - Size: Large format for easy handling and multiple tests - Included: Touchstone (testing acid sold separately or as part of selected kits)