Copper Film (image) American Institute of Physics Caption This is an optical microscope image of a copper film mostly destroyed during graphene growth. What was a continuous copper film has decomposed into grey areas of bare sapphire, rings and irregular patches of copper that appear in a rainbow of colors due to oxidation, and small star-shaped islands of graphene, which appear bright because the graphene protects the copper from oxidation. Credit David L. Miller, NIST Usage Restrictions This image may be used only with appropriate caption and credit. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.