Insulation works by slowing conductive and convective heat flow, while radiant barriers and reflective insulation reduce radiant heat gain through reflective surfaces in contact with air spaces.
Mineral wool is a fiber insulation made from natural materials, similar to fiberglass but not from glass.
Attic insulation levels are measured by R-Value, which indicates resistance to heat flow. Most attics should be insulated to R-38, or about 10 to 14 inches, depending on the insulation type.