ROBERTO DE GUGLIEMO / SCIENCE PHOTO LIBRARY ROBERTO DE GUGLIEMO / SCIENCE PHOTO LIBRARY
Crystals of smoky quartz. 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. This specimen measures 18 x 14 cm and was found in Pedra Alta's Mine, Sao Geraldo do Baixio, Brazil.
Model release not required. Property release not required.