These tourmalines, variety elbaite, are from Minas Gerais, Brazil. Elbaite is part of the Tourmaline Group of minerals. It is a silicate and it contains the elements Al, B, H, Li, Na, O, and Si. Pure elbaite, which is rare, is colorless but the presence of trace elements in the lattice of the crystal are responsible for producing a variety of colors (including green). These crystals host rosette clusters of lavender lepidolite ( the lithium rich variety of mica). The tourmalines are translucent under bright light and they have glassy transparent exteriors. This double terminated piece measures 1 1/8 x 1/2 x 5/16 inches or 28 x 12 x 7 mm.