Video S2 - polarimetry of shell as a function of vertical position

Polarimetry imaging of the Pinctada fucata shell as a nacre portion of the shell was moved vertically through the beam, shows the repetitive nature of the polarization fringes within the sample. The sample was moved vertically through the beam while the horizontal position was held constant such that the beam was transmitted through nacre. The regions of low intensity within the images are indicative of regions of the sample where the transmitted light did not match the selected polarization filter, which was held constant throughout the movie. As can be seen within the movie, there are repeating fringes of high and low intensity throughout the shell.