Bluestone

Bluestone was the Realms name for sodalite, or ditroite, which was a rich blue but soft and brittle mineral. Sometimes bluestone had veins of pink, white, cream, and yellow.

Description
These ornamental stones were found in the Storm Horn Mountains, the Thunder Peaks and other geologically old mountain ranges. It was usually cut cabochon and polished or tumbled smooth; very rarely it was hard enough to be cut in facets. A typical stone had a base value of 10 gp.