Difference between lens and mirror?

mirror are highly reflecting surfaces. A mirror is made by silvering a glass surface with an amalgum of mercury and tin..when  light falls upon the reflecting surface it enters into the glass and is reflected from the silvered surface.

a lens is  a homogeneous transparent medium bounded by two curved surfaces or one curved surface and one plane surface. The curved surface may be sphercal, cylindrical or parabolic.light goes a phase of refraction when it passes through a lens.