A township center where an extravagantly sculpted gabbro fountain stands, depicting the entwining forms of numerous menacing serpents that spew mercury from all sides of the fountain within it.
Due to the temperature of the area, the mercury being spewed rapidly turns into vapor, spreading a noxious mist of debilitating poison.
Those not attuned to the poison of mercury may suffer severe poison damage upon breathing the vapors...
@BrianBinh Glad you were able to learn something new! Being able to find an excuse to look varieties of stones are the reason why I love underground settings in a dungeon.