The property possessed by some crystals, of showing different colors when viewed in the direction of different axes.
When light passes through a doubly refractive gemstone, the light is split into two rays which are polarized at right angles to each other and travel at differing velocities through the gemstone. In some colored doubly refractive gemstones, these rays may emerge differing in shade or color. When this occurs, the rays are said to have experienced "Differential Selective Absorption".
(ple'-o-chro-sim) The phenomenon in which the color of a mineral varies or changes with orientation.
the phenomenon of different colors appearing when certain crystals are viewed from different directions
The property of most doubly refractive colored minerals of showing two or more colors when viewed in different directions by transmitted light. Not the same as Photochroism. See also Dichroism and Trichroism.
Is the property of a gemstone where it has more than two colors. An example of a gemstone showing this characteristic is Iolite which shows a violet blue, light blue and yellow gray color
(from Greek pleion, "more," and chros, "colour"), in optics, the selective absorption in crystals of light vibrating in different planes. Pleochroism is the general term for both dichroism, which is found in uniaxial crystals (crystals with a single optic axis), and trichroism, found in biaxial crystals (two optic axes). It can be observed only in coloured, doubly refracting crystals.
The ability of certain gems to display two or more colors when viewed from different angles.
In a doubly refractive crystal, a light beam reflects two different rays. The eye cannot normally see both rays at the same time, but by moving the stone, the eye will observe both rays. The result? The stone exhibits one of two or more different colors (or two or more different color depths) from each angle. This effect is known as dichroism (two-color) or the more common pleochroism (many colors). Tourmaline is a perfect example.)
Change of the color of certain minerals during stage rotation; seen in plane polarized light.
(minerals). The changes in color when some transparent minerals are rotated in plane polarized light. It is expressed in terms of the nature and intensity of the color change.
Pleochroism is the property of having more than two colors, especially when viewed from different angles. In pleochroic minerals, a single stone will show many colors (in the case of Iolite, violet-blue, light blue, and yellow-gray will be visible).
Pleochroism is an optical phenomenon where due to double refraction of light by a colored gem or crystal, the light is divided into two paths which are polarized at a 90° angle to each other. As the divided light beams follow different paths within the stone and are traveling at different speeds, they may have the result of differential selective absorption, thus when they leave the crystal they have different colors, making the stone seem to be of different colors.
