KAJ R. SVENSSON / SCIENCE PHOTO LIBRARY KAJ R. SVENSSON / SCIENCE PHOTO LIBRARY
Polished agates. Several polished agate stones showing marble-like patterns. Agate is a type of chalcedony, a crypto-crystalline variety of the mineral quartz (silicon oxide). The presence of impurities can give it a wide range of colours which may be distributed in regular bands or zones, in clouds or in dendritic forms.
Model release not required. Property release not required.