[fch42]

Hmm; so the only thing that can "easily" decay into the stable forms of carbon - C12 and C13 that is - is N13 (β+ to C13 with "minutes" half-life). Nothing decays into C12, since N12 or O12 would have half-lifes so short as to make them "doubtful" isotopes.

But Nitrogen wouldn't crystallise in a diamond lattice; nevermind the crystal absorbing "heat" from the radioactive decay disturbing positions temporarily, there's just no way to arrange Nitrogen and Carbon atoms into similar locations of a crystal lattice. This sort of "transmutation" isn't even science fiction, it's only a dream

(follow your dreams but think a few times before trying to make money off them)