This is a photograph of the cuticle pattern on a commertial
"wool" yarn fiber.
Transmitted Oblique Illumination
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.
