The three human skin flakes here are easily seen in this tapelift from a home. They all show stress birefringence.
Transmitted Off Crossed Circular Polarized Light Illumination
Significance in the Environment:
Human dander varies from isotropic to particles with stress birefringence. The stress birefringence of human skin flakes tends to be low. The
refractive index of human skin flakes tends to be around 1.550 but will vary with stress and oil content.