Contents

21 December 1990
Vol 250, Issue 4988

About The Cover

Optical image of a 6.0-micrometer-thick single-crystal diamond film grown by chemical vapor deposition, together with gem-cut natural diamonds. Strain in the crystal causes the various colors in polarized light. Such films may form the basis for new kinds of electronic and optical devices. See Editorial, page 1637, and Molecule of the Year, p. 1640. [Diamond film made by A. Badzian and T. Badzian, micrograph by Barry Scheetz, Pennsylvania State University, University Park, PA 16802; photograph of gem-cut diamonds by Randy Duchaine/The Stock Market]