Dumortierite, Vaca Morta Quarry, Bahia, Brazil
Dumortierite is an aluminum iron borosilicate mineral that doesn't get much attention in the world of fluorescence, but is a lovely fluorescent species nonetheless. This fist-sized specimen features a thick layer of blue dumortierite on a matrix of white milky quartz, from the Vaca Morta (yes, dead cow) quarry in Serra da Vereda, Boquira, Bahia, Brazil. This specimen measures 10 x 9 x 5 cm, and weighs 475 grams.
Photo on left shows fluorescence under short wave UV (254nm). Visible light photo on right. Click on the above images for a larger view.