I thought ZnO crystals were a well known demo specimen for SEM work. At least when I was at Cornell in 1975, they were a favorite item for demonstrating the power of a SEM. I remember going to the SEM lab on Olin Hall with a friend who had bought some cheap SEM time at 2:00 AM. The most memorable item we looked at was the ZnO smoke sample.
Zinc burning in air forms perfect tetrahedral pointy crystals in a broad range of sizes that resemble a caltrop from outer space. See:
I thought I'd have no trouble finding an image of these crystals, but an extended Google search didn't bring up a single example. Perhaps they have been forgotten. It would be interesting to see them again.
Thursday, May 21, 2009
More on Zinc Oxide
David Speck wrote with more on Zinc Oxide