Dumortierite was named after the French scientist, M.E. Dumortier. Dumortierite is best known in its massive form, making an attractive violet and blue decorative gemstone when polished. Reddish brown and red varieties also occur. Prismatic crystals bigger than 1mm are very rare.
Demortierite is also found intergrown with rock crystal (colourless quartz) and is then called dumortierite quartz. This material is generally cut in cabochon or polished to make decorative stones.
Most gem-quality material is found in Nevada (USA). Other localities include France, Madagascar, Norway, Sri Lanka, Canada, Poland, Namibia and Italy.