Uses: Carbon forms numerous and varied compounds with limitless applications. Many thousands of carbon compounds are integral to life processes. Diamond is prized as a gemstone and is used for cutting, drilling, and as bearings. Graphite is used as a crucible for melting metals, in pencils, for rust protection, for lubrication, and as a moderator for slowing neutrons for atomic fission. Amorphous carbon is used for removing tastes and odors.