wigmund:

From Mindat.Org Photo Of The Day; November 10, 2015:

Dumortierite: (Al,Fe³⁺)₇(SiO₄)₃(BO₃)O₃; Quartz: SiO₂

Locality: Vaca Morta quarry, Serra da Vereda, Boquira, Bahia, Brazi

Dimensions: 3.5 cm x 1.8 cm x 1.0 cm. Rare and wonderful Dumortierite crystals forming a lovely garden within this non polished, natural double terminated 3.5 cm. Quartz crystal. Val Collins