Various
kind of stone, brick, terra cota, slate, sand stone, etc.
can be painted or textured with plaster and color to reproduce
a "real" effect, in interior and exterior surfaces.
<<Before and After of a faux-stone barn.
English Carriage house. Faux stone and painted hinges
converts a steel pole barn into a stone carriage house.
A bit of whimsy is a bare light bulb seen inside.