Silicon

From Slackerpedia Galactica

Silicon is the main material used in artifically large breasts. I'm sure it has some other uses but I just can't think of them after typing the words "large breasts".

Due to it's relationship with Carbon in the periodic table of elements some have suggested that life forms could be made out of silicon. The Horta, for example. I'd hate to have to treat an injured one, though ("I'm a Doctor, not a bricklayer!").