De luna

The moon is made of silver. This is why werewolves transform under the light of the full moon; the high silver content of the light irritates their body and causes transformation as an inflammatory reaction.

While this had been predicted by alchemists since at least Paracelsus' time, the observations of Newton on the properties of prism-dispersed moonlight were the first strong scientific evidence of the composition of the moon. True confirmation, of course, did not come until the Apollo missions, when the first verifiable moonsilver was brought back to earth.

Sadly, few samples of true moonsilver could be collected during the short lifetime of the program; these still exist, closely guarded by NASA, with a very few samples available for research to selenologists and theoretical alchemists. Still, this research has been enough not merely to establish the properties of moonsilver — and, with reference thereto, to disprove the authenticity of every historical relic ever claimed to contain it — but has recently also resulted in the development of an alchemical process to synthesize moonsilver. (This synthetic moonsilver is most commonly marketed under the trade names Dianite and Tilion, or the generic name synthelune, but ‘moonsilver’ is still the most commonly heard term.)