Powdered iron is magnetic, but powdered sulfur is not. What occurs when they form a mixture in a beaker at room temperature?
Not much; chemical change has not occurred.
This is a typical high school experiment to demonstrate the difference between chemical change and physical change. Simply mixing the powders is a physical change; and the iron powder could be separated by magnet.
Heat the mixture up, and the sulfur oxidizes the iron. The iron sulfide is not a magnetic material.