Last updated on August 29th, 2020 at 01:27 am
Erasmus Bartholinus discovered in 1669, that, when a ray of light is refracted by a crystal of calcite it gives two refracted rays. This phenomenon is called double refraction. Calcite is crystallized calcium carbonate (CaCO3). It crystallizes in many forms and can be reduced by cleavage or breakage into a rhombohedra.