Dichroscope

A dichroscope is a pocket instrument used in the field of gemology, and can be used to test transparent gemstones (crystals).

Experienced gemologists, observing the pleochroism of some gems, can successfully detect gemstones from other artificial stones using this instrument.

This makes the process time-consuming and difficult, though it is the most economical way to get results.

[1] A calcite dichroscope shows a gem's pleochroic colors in contrast with one another, allowing the viewer to easily determine whether the stone is singly or doubly refractive (uniaxial or biaxial, respectively).

Calcite dichroscopes are effective because the inner calcite component is able to split the entering light beam coming through the stone, revealing whether the stone is isotropic, uniaxial or biaxial.