Tourmaline, Schorl cluster - Minas Gerais, Brazil (MS2902e)

Several Discrete Tourmaline crystals have inter-grown into a golf-ball-sized specimen weighing about 70 grams and measuring about 40mm x 40 mm x 30mm.  Other minerals, such as feldspars add contrasting color.  The yellow cube is a typical bouillon cube, measuring about a half-inch on a side, photographed for size reference.