- pleochroism of a uniaxial crystal such that it exhibits two different colors when viewed from two different directions under transmitted light.
- the exhibition of essentially different colors by certain solutions in different degrees of dilution or concentration.
- a property of a uniaxial crystal, such as tourmaline, of showing a perceptible difference in colour when viewed along two different axes in transmitted white light
- a property of certain solutions as a result of which the wavelength (colour) of the light transmitted depends on the concentration of the solution and the length of the path of the light within the solution
