“ Alchemical Gold - popular in the weapons of the nobility, this allows for gold to be used in their swords and lances without the fear of the metal bending, deforming or otherwise breaking in combat.”
“ Mining in a certain area turns all exposed skin (maybe just parts that are actively disturbing the chemicals that cause the reaction) of the those doing the mining to a dark blue color. Will wear off taking as many years/days spent in the mine. ... meeting a party of blue-skinned humans armed with pick-axes etc. Strange disease? Demon offspring? Curse? If they meet only one ex-worker, they will very carefully listen to any stories he says, no matter if drunken or insane, or just makes up to get a beer.”
“ A village or town's dance was first taught to them long ago by the faeries.”