More on Calcite Crystals
They are electromagnetically sensitive (react to and influenced by electromagnetic fields)
Optics studies on calcite show that it is able to refract electromagnetic radiation from a very wide range of wavelengths (well beyond visual light), and is an optic polarizer (divides a beam of light into 2 beams with opposite polarization)(http://www.sciner.com/Opticsland/Calcite.htm)
The pineal gland has photosensitive 'retinal' cells
Are calcite crystals involved in sensation for these cells and how does their geometry effect their optical properties?