Amaratha

Amaratha is also known as shieldstone and is unique to the Realms. Found as small lumps or nodules in deep rock strata, amaratha is soft and yields greenish white to pale green gemstones that can be set into body jewelry or any setting where it is protected from damage or wear. Shieldstone attracts and absorbs electricity in a ten foot (three meter) radius, protecting all within this area until it vaporizes. A large quantity of amaratha could absorb a natural or magical lightning bolt. A typical one-inch (two and a half centimeter) diameter sphere has a base value of 5000gp