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.