One of your better items Cheka - there are still some spelling errors which should be addressed (Especially in the summary! This is your attention-getter - make it perfect!)- but otherwise a cool item with a logical downside. Go to Comment
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.