In Dorothy Dunnett's book The Spring of the Ram she has a line on page 197 that I particularly love:
Calmness was a weapon and a defence; beauty was only a weapon and best left alone.
At lunchtime I was reading a book with a line almost as good:
And beauty's a tool, like a knife or a drill or the little metal files you use to dig dirt from beneath your fingernails.
Cagebird by Karen Lowachee, p. 9.