What is a bireflectance?

Answer 1

A bireflectance is an optical effect in which the amount of plane polarized light reflected from a mineral sample varies as the sample is rotated.

Answer 2

Bireflectance is the property of a material to reflect light in two different directions, often resulting in a distinct pattern or two different reflection angles. This phenomenon can be observed in certain crystals and minerals due to their unique properties.