Disthene

Disthene is abundant in the Realms, and is easily cleaved making it difficult to cut in facets without splitting. Unflawed disthene is difficult to find but comes in crystals ranging in color from dark blue to pale green. Good quality blue facet-grade crystals are the most prized at double the base value. Disthene is also known as kyanite. A typical stone has a base value of 10gp.