Light can be thought of as a ray or a particle.  The particles are called photons and each photon of light is polarised in some manner as it is created. Thus ordinary light is unpolarised as it contains a mixture of photons of randomly different polarisations.   The human eye can not detect polarisation in light without using special filters.  Polaroid filters only let light pass that is in one plane of polarisation and this can be used, in special spectacles, to prevent glare from car headlights and some other sources.  However, such filters can not detect circularly polarisation as the direction of polarisation is spiralling in a screw pattern, but I hope you now understand a little more about light.  Here are two websites that go into a lot more detail.

http://acept.la.asu.edu/PiN/rdg/readings.shtml  (Patterns in Nature)

http://www.uwgb.edu/dutchs/petrolgy/genlight.htm