Ferrofluids, aerogel, perfluorocarbons, elastic conductors, non-Newtonian fluids, transparent alumina, and carbon nanotubes are the 7 man-made substances. If you want to read about the amazing details go to this link.

http://www.cracked.com/article_17476_7-man-made-substances-that-laugh-in-face-physics.html

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