Wool
                This is a photograph of the prepared "Common Goat" slide
                  from the Cargille Hair Standard set. The plane of focus is on the
                  center of the part of the hair filled with mounting medium so that the detail of the
                  medulla structure is visible.
                
              
              
                Transmitted Crossed Linear Polarized Light
                
Definition/Function:
                Significance in the Environment:
                Characteristic Features:
                Wool has a refractive index along its length of about 1.56 and perpendicular to its
                length of about 1.55.
                It has a birefringence of about 0.01 and a positive sign of elongation.
                Associated Particles:
                References:
                Von Bergen, Werner, WOOL HANDBOOK: VOLUME ONE, Interscience Publishers, pp. 364-365,
                1963