Lasing due to color centers in an Al<sub>2</sub>O<sub>3</sub>:Mg crystal

Boiko, B. B.; Шкадаревич, А. П.; Zhdanov, E. A.; Kalosha, I. I.; Koptev, V. G.; Demidovich, A.A.

doi:10.1070/qe1987v017n05abeh008984

Cited by 5 publications

(2 citation statements)

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“…A good general review is provided by Rossman (1987, 1988);Häger (2001) orangy yellow (Kvapil et al, 1973;Schmetzer, 1981;Schmetzer et al, 1983;Boiko et al, 1987;Emmett and Douthit, 1993;Häger, 1993 …”

Section: Color In Corundummentioning

confidence: 99%

Beryllium Diffusion of Ruby and Sapphire

Emmett¹,

Scarratt²,

McClure³

et al. 2003

Gems & Gemology

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Over the past two years, the heat treatment of corundum involving lattice diffusion of beryllium (Be) at temperatures over 1800°C has become a major issue in the gem trade. Although initially only orange to orangy pink ("padparadscha"-like) sapphires were seen, it is now known that a full range of corundum colors, including yellow and blue as well as ruby, have been produced or altered by this treatment. An extension of the current understanding of the causes of color in corundum is presented to help explain the color modifications induced by Be diffusion. Empirical support is provided by Bediffusion experiments conducted on corundum from various geographic sources. Examination of hundreds of rough and faceted Be-diffused sapphires revealed that standard gemological testing will identify many of these treated corundums, although in some instances costly chemical analysis by mass spectrometry is required. Potential new methods are being investigated to provide additional identification aids, as major laboratories develop special nomenclature for describing this treatment.

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Section: Color In Corundummentioning

confidence: 99%

Beryllium Diffusion of Ruby and Sapphire

Emmett¹,

Scarratt²,

McClure³

et al. 2003

Gems & Gemology

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“…For instance, green colour arises from the combined presence of Fe 3+ (yellow) and Fe 2+ -Ti 4+ (blue) [67]. Purple or violet occurs as a result of the existence of both Cr 3+ (red) with Fe 2+ -Ti 4+ (blue), whereas the orange is envisaged by cohabitation of the h•-Cr 3+ trapped hole (occurring as a result of the presence of Mg 2+ ) (yellow) and the Cr 3+ (pink) [66,[69][70][71][72].…”

Section: Colourmentioning

confidence: 99%

Intriguing minerals: corundum in the world of rubies and sapphires with special attention to Macedonian rubies

et al. 2021

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This lecture text presents features of the fascinating mineral corundum and its gem varieties, ruby and sapphire. The geologic occurrences of its varieties and the best-known world localities are presented in detail. The mineralogy and crystallography of corundum, as well as its occurrence forms, are discussed. The origin of their colour varieties and their usage are described, in addition to their important physical characteristics. Applications in the watch and laser industries and as an abrasive material, among others, are included. The ruby variety from dolomite marble in North Macedonia exhibits the unique optical phenomenon known as diasporescence-the inclusion of diaspore crystals in the corundum matrix. This phenomenon affects the parting of corundum crystals and influences their colour, density and hardness. Therefore, special attention is paid here to morphological and physical characteristics of the Macedonian gem corundum.

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