What mineral would likely cause boiled water to turn brown and --?
a dark grey crust (likely oxidation) to form on a stainless steel sauce pan?
The pan has never been used except to boil water and the lid is always on except when adding/deleting water.
Water is from a well and has passed the normal tests (bacteria and clarity).
Reservoir is basaltic in nature so likely that the water is heavily mineralized.
I don't believe it is dangerous in any way - just curious.
The crust builds for a while then chips off and is near impossible to scrape off (without damaging the pan)