These danburite crystals are from Charcas, Mun. de Charcas, San Luis Potosi, Mexico. Mining of the ore bodies in this area began in 1583. The ore bodies contained sulfides of silver, lead and zinc along with other accessory minerals. One of the most famous of these minerals is the outstanding examples of danburite found there. They contain the elements Ca, B, Si, and O. This is a cluster of parallel twin crystals with smaller crystals that are partially covered with calcite crystals (Ca, C, O) on one side. These danburites have a light pastel pink color and a glass luster. They are mostly translucent with transparent and etched areas near the surface. This piece measures 3 3/8 x 1 5/8 x 1 1/8 inches or 85 x 41 x 28 mm.