Pseudochromasia
With Pseudochromasie (from Greek pseudo deceive and chroma color), the color of fabric is called, which is not due to coloring substances. A pseudochromatic fabric often shows many colors at the same time.
With idiochromatic or allochromatic substances, the color is brought about by a chromophore . In most minerals, the chromophore contains an element of the transition metals .
In the case of pseudochromatic substances, on the other hand, the color is created by interference . This can be seen, for example, in the play of colors in the minerals labradorite or ammolite . The annealing colors that coat many weathered minerals such as bornite are also caused by interference in thin layers . Other examples are opal and mother-of-pearl .
Among the rocks, the anorthosites and the so-called larvikites are the best known examples of the appearance of this optical effect in crystal lattices.
See also
literature
- Raymond Perrier: Les roches ornementales . Edition pro roc, Ternay 2004, ISBN 2-9508992-6-9 , pp. 180 .