We usually feature quartz crystals or fluorite crystals, but today’s crystal is somewhat different. To celebrate the first day of winter, here are some photos of snowflakes taken with a Low Temperature Scanning Electron Microscope (LT-SEM). The photos were taken by members of the Electron and Confocal Microscopy Laboratory, Agricultural Research Service, U. S. Department of Agriculture. From top to bottom, left to right, there are some needle crystals, a snow crystal coated in rime, a hoar crystal, a common snow crystal, a snowdrift from St. Louis Creek, a close-up of packed snow, a side plane crystal, and the traditional dendritic snow crystal. Suddenly I understand why there are so many different types of snow. More photos of snowflakes here.