Specular reflection is the perfect, mirror-like reflection of light (or sometimes other kinds of wave) from a surface, in which light from a single incoming direction (a ray) is reflected into a single outgoing direction^[1].

Here you can find settings and information about controlling specular reflections in PyMOL. Specular reflections can make a surface look smooth like thing plastic or metal/glass.

References

• http://en.wikipedia.org/wiki/Specular_reflection