This is a photo of a thin slice of a molar tooth placed in the middle of two polarizer filters.
The first polarizer blockes the phenomenical horizontal light wavelengths orientation, whereas the second one, placed 90 degrees offset (in respect to the first polarizer) blocks the phenomenical verticalwavelengths.
The pollarizers also produce the spliting of white light, as shown by the rainbow effect in some aerias of the molar tooth.
The shot was taken using a Nikon D7500 and a Tamron 90mm f2.8 Macro Lens.