Dumortierite

Dumortierite often forms in an attractive blue color and can be used as an ornamental stone. Though it is most commonly perceived as blue, especially in lapidary use, other colors include purple, pink, gray and brown. Dumortierite specimens are composed of dense fibers, giving them a tough durability.

Dumortierite often forms as inclusions in Quartz, and this combination results in a natural blue Quartz gemstone. These are known in the gemstone market as "Dumortierite Quartz" and they are becoming increasingly popular as a minor blue gemstone. Dumortierite is named after French paleontologist Eugene Dumortier (1803-1873).

For additional information, see the gemstone section on Dumortierite.

Never in individual crystals. Most often as radiating sprays, as fibrous masses, columnar, compact, massive, and as grainy splotches on matrix.

In high temperature, aluminum-rich regional metamorphic rocks, in boron-rich granite pegmatites, and in hydrothermal replacement deposits.

Dumortierite is not a common mineral, and only a handful of localities have produced quality specimens. The type locality where this mineral was first discovered is the Ducarre's Quarry, Beaunant, Rhône, France. Small embedded fibrous groups of Dumortierite have been found in the Waldviertel area, Lower Austria, Austria; and violet-blue acicular crystals from Chiavenna, Val Schiesone, Lombardy, Italy. A deep blue form in relatively large crystals comes from Sahavina and Ambositra, Antananarivo Province, Madagascar. Fine radiating Dumortierite needles have come from Cucucha, Canta Province, Peru; and a deep blue Dumortierite included in Quartz from Macaúbas, Bahia, Brazil (where it is known locally as "Bahia Blue Quartz".)

In the U.S., blue and lavender Dumortierite in dense fibrous form comes from the Dehesa Dumortierite Deposit, near Alpine, San Diego Co., California. Other California localities include the Temescal Wash, Corona, Riverside Co.; and Ogilby, Cargo Muchacho Mountains, Imperial Co., California. Dumortierite was also found in Oreana, Pershing Co., Nevada; and in the Clip Mine, Yuma Co., Arizona.