Zircon

Zircon is a brownish crystal found in igneous (volcanic) rocks. Zircon attains its pale blue shade with heating and cutting (usually facet-cut). Zircons are occasionally passed off as more valuable gemstones, though anyone with the slightest knowledge of gems (jeweler, dwarf, or even an adventurer of long standing) can identify the difference. A typical specimen has a base value of 50gp.