First link worked for me... might have to stop in at my local Lowes and see what other styles they have... I seem to remember some kind of lightweight 'stone look' siding material at Menards, but don't recall what it was made from...
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That stuff is a concrete product. Some of it may even be open or closed cell foam, with tinted stucco over it. I would suspect that it may be treated to prevent termite/insect infestation.