The mineral matter in bone (hydroxiapatite) is arranged in concentric layers and is an interesting subjet for study under polarized light.
Leitz NPL Fluotar 16X 0.45. Magnification on 7D sensor 25X. Levels slighly corrected.
1- Brightfield

2- Crossed polarizers

3- Crossed polarizers and full wave plate

4- Crossed polarizers and 1/4 wave plate

5- Crossed polarizers +1/4 wave plate + objective DIC prism as retarder

6- DIC

I prefer the DIC and BF ones, what do you think?