ROBERTO DE GUGLIEMO / SCIENCE PHOTO LIBRARY ROBERTO DE GUGLIEMO / SCIENCE PHOTO LIBRARY
An aggregate of colourless quartz and dark green tourmaline crystals. Quartz (silicon oxide) is colourless when pure, but the presence of impurities can give a range of colours including white, pink, yellow, blue, green and smoky brown. The pure, colourless variety is known as rock crystal and is highly prized by collectors. Tourmaline is a complex silicate of aluminium and boron and can also occur in many different colours. This specimen measures 14 x 12 cm and was found in Conselheiro Pena, Brazil.
Model release not required. Property release not required.