Refractive indexes

Refractive indexes.

The refractive indices of minerals vary; this is an important hallmark, allowing the determination of minerals often with very similar properties.

Optically isotropic minerals, i.e.. amorphous, like opal, and crystallizing in a regular pattern, …

Refraction of light in the crystal

Refraction of light in the crystal.

Light rays passing through a vessel filled with water are refracted, if they do not hit the water surface at right angles. The greater the angle of incidence of the light rays, the greater their deviation from the original direction. If it does …