"Blue" Water I live in an area that used to be used for mining of anthracite coal, actually a lot of it still is. Recently I "stumbled" upon an old strip mine in the woods. No surprise though around here they're everywhere. There were two surprising things about this particular strip mine. 1. The mine was filled with water, it has been that way for many years. 2. The water in this mine is an almost florescent blue color. I've been trying to figure out what could possibly give it this strange color. At first I thought maybe copper but copper generally turns green in reaction to water. After seeing some of the sediment from the bottom of the mine, I thought maybe it was iron since it had almost like a rust color to it. However I still have a feeling that is not correct. Are there any minerals that are commonly found close to anthracite coal that would give water a color such as this? Also do it post any kind of environmental threat?