in several different metals (i had only heard of tin whiskers) fern like arms grow, made of the same metal. this has caused problems in spacecraft, servers around the world etc (the whiskers act as jumpers in a circuit and cause a short). very interesting, read:
http://en.wikipedia.org/wiki/Tin_whiskersThis post was edited by juliusjuice on Sep 22 2010 01:42pm