 |
 |
|
Blumentritt, F. & Fritsch, E. (2021) Photochromism and Photochromic Gems: A Review and Some New Data (Part 1). Journal of Gemmology, 37 780–800.
Added by: Richard Baschera (2022-02-21 13:51:39) Last edited by: Richard Baschera (2022-02-21 13:54:05) |
| Type de référence: Article DOI: 10.15506/JoG.2021.37.8.780 Numéro d'identification (ISBN etc.): {1355-4565} Clé BibTeX: Blumentritt2021a Voir tous les détails bibliographiques  |
Catégories: MIOPS Créateurs: Blumentritt, Fritsch Collection: Journal of Gemmology |
Consultations : 1/411
Indice de consultation : 10% Indice de popularité : 2.5% |
| Résumé |
|
Photochromism is defined as the reversible change of colour caused by exposure to `light' (visible and UV wavelengths, sometimes extended to X-rays). The species covered in part 1 of this article include sodalite (hackmanite), marialite (scapolite group), tugtupite, spodumene (kunzite), diopside and zircon. We review available data on such gems and provide a systematic approach to their photochromic behaviour, describing the discovery of the colour variation, the photochromic colours known, their corresponding UV-visible absorption spectra, and facts or hypotheses regarding the origin of the phenomenon. Where available we include new data to supplement the information available in the literature. Sulphur-based polyanions are thought to be responsible for photochromism in some aluminosilicates (i.e. hackmanite, marialite and tugtupite). More generally, the phenomenon can be explained by movement of an electron (either an electron centre or a hole centre) from one `defect' ('colour centre') to a different one. However, the exact nature of the defects involved at the atomic and electronic levels are essentially unknown. This article also discusses proper use of terminology, and we propose that photochromism is more accurate than, for example, tenebrescence, colour change or chameleon effect.
|