I was thinking of crushing up some common limestone for microminerals because the water where I live has nearly zero calcium content. So I read about the trace elements of limestone and It says chromium is common at about 30ppm, and chromium VI is toxic, but it only occurs at tectonic boundaries and high-energy industrial processing.
If I crush up mountain limestone which is full of white calcite, what kind of nasty chemicals could result from that, compared to drinking water from a village fountain from the same area?