Thanks for the help and interest!
I can try to describe how "Stofflighet" is used in the Norwegian photographic tradition.
It is the sensation of seeing, then experiencing the quality of and almost being able to feel like touching of the surface of an object in the photograph. It can be of fat and shiny leather, or the wooliness of woolen clothes, or the exact grittyness of rocks, or the structural fragility of millions of sand grain, or the dry fibres of wood, you can go on and on.