Siderite iron ore (sedimentary rock), from McLeod Mine, Wawa, Ontario. This sedimentary iron carbonate rock was an excellent material for extracting iron ore. Shiny fool's gold (pyrite) can been seen on the smooth surface of this rock. When the rock was processed to extract iron ore, pyrite broke down into iron and sulphur. The sulphur caused acid pollution in the direction of the prevailing wind (east) and transforming the area into a desert landscape.
