Capsaicin molecule necklace.
Buy here: http://shpws.me/qZhP
Capsaicin (8-methyl-N-vanillyl-6-nonenamide) is the active component of chili peppers, which are plants belonging to the genus Capsicum. It is an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact. Capsaicin and several related compounds are called capsaicinoids and are produced as a secondary metabolite by chili peppers, probably as deterrents against certain herbivores and fungi. (from Wikipedia; comes without the chain)
Can be used as a pendant on a necklace, keychain, earring, or whatever you find it useful for.