Main Question or Discussion Point
Asphalt in roads sometimes appears very black through polarizing glasses. I imagine it is possible to measure the angle of reflection with the highest degree of polarization, θ (Brewster's angle), for asphalt. For transparent materials, the refractive index is related to θ, n = tan θ. Is the refractive index a property that exists for nontransparent materials like asphalt as well?