ARNOLD FISHER / SCIENCE PHOTO LIBRARY ARNOLD FISHER / SCIENCE PHOTO LIBRARY
Sample of cassiterite. Cassiterite, a form of tin oxide, occur either as stubby prismatic crystals or (as here) a black granular mass. When cut in section and polished, the inner banded structure has the appearance of burr wood, known as 'wood tin'. Cassiterite is a major ore of tin. This sample was found in Cornwall.
Model release not required. Property release not required.