“ 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.”
“ 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.”
“ Could be used for killing a certain animal...a prized animal. The bones must be carefully buried or disposed of lest a sorcerer get a hold of it. With the bones of the dead creature the sorcerer can kill the hunter.”