BIOPHOTO ASSOCIATES / SCIENCE PHOTO LIBRARY BIOPHOTO ASSOCIATES / SCIENCE PHOTO LIBRARY
Citrine crystals (silicon oxide, formula: SiO2). This mineral is a variety of quartz that is used as a gemstone. Since it is rare in nature it is often obtained by heat treatment of another variety of quartz, the purple amethyst mineral, to produce the orange colour seen. In nature, heat from molten rocks may produce citrines from amethysts.
Model release not required. Property release not required.