Angry Enderman by TheBigLiveTourFan on DeviantArt Amethyst Stone Concave Tunnels (2 gauge 1 inch). ONE PAIR of amethyst stone double flared concave tunnels. These plugs are absolutely gorgeous and are polished to a smooth finish. Wearable area for sizes 8 gauge 1 inch is 3 8 inch. Additional Info: Stone items are all hand made so they may slightly vary in size, color, and shape. All of our stones are guaranteed to be within 1mm of the stated size. If you need an exact measurement or better description of the item, feel free to email us before ordering. Stones are also a fragile material and can break if dropped or not handled correctly.