22 November 2011


Posted by Callan Bentley

On our way up Compton Peak the other day, my field crew spotted some fibrous growths of ice growing up and out of the ground (perpendicular to the surface of the mountain):

(Joe’s hand lens for scale.)

The fibrous habit made me think of asbestos, and then I wondered whether the different shapes of ice crystals reflect different mineralogical arrangements of the H and O atoms, and if they are technically different minerals (you know: polymorphs, like calcite and aragonite, or graphite and diamond). Anyone got insight on that? Can we see these polymorphs in human-experiential meteorological conditions? Or are they crystallographically identical ice that just takes on a variety of habits?  Mindat and WebMineral suggest the most common form of ice is hexagonal, but this site suggests (and shows) a variety of crystallographic forms, with clever names like “Ice II” and “Ice III.” Apparently lab experiments have produced varieties needing names going all the way up to Ice XV (that’s “15”), including Ice IX, which is different from Ice 9.