Crystals of green tourmaline and pink lepidolite. Tourmaline is a complex silicate of aluminium and boron which occurs in many colours including black, brown, blue, green, red and pink. Lepidolite (hydrous potassium lithium aluminium silicate) is a type of mica. This specimen measures 11 x 6 cm and was found in Limoeiro's Mine, Virgem da Lapa, Brazil.