This tourmaline, variety elbaite, is 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). This crystal hosts rosette clusters of lavender lepidolite ( the lithium rich variety of mica). The tourmaline has an opaque core that is covered with glassy transparent exterior. This piece measures 2 15/16 x 7/8 x 3/4 inches or 49 x 22 x 19 mm. It weighs 40 grams.