All monolith natural stones are stone type that have been selected specifically for use in the warm monolith fireplace.
The monolith gives off most of its heat as soothing, long-wave radiated warmth. The radiated warmth arises from the hot surface of the natural stone casing. High temperatures can initiate reactions in natural stones whose colour or surface has been changed by chemical processes (colour intensifiers, resins). This may cause marks or odours.
This is why monolith natural stones do not undergo any processes to intensify colour or apply resin. Otherwise we cannot guarantee 100% that odours/ marks will not occur, or that harmful fumes will not form.