Beryllium Diffusion of Ruby and Sapphire

Abstract

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.

Identification and Durability of Lead Glass-Filled Rubies

“…Most significantly, many of these stones revealed dense clouds of fine, unaltered rutile needles following the hexagonal structure of the ruby (figure 6). This is clear evidence that these stones had not been exposed to temperatures high enough to damage rutile (greater than 1,500°C; Emmett et al, 2003).…”

Gemstone Enhancement and Its Detection in the 2000s

“…The story is well documented by Emmett et al (2003). At first, the reason for the orange surfacerelated color zone could not be determined.…”

“…Severely heat-damaged inclusions were found in many of these treated stones (Roskin, 2003a;Schmetzer and Schwarz, 2005), but they only indicate that the stone was treated at extreme temperatures-they do not prove the presence of Be (Emmett et al, 2003). After a time, we started to see Be-diffused blue sapphires treated by an even newer method that showed no surface-related characteristics and created unusual inclusions (figure 12; Choudhary, 2006;Kitawaki and Abduriyim, 2006;Roskin, 2006;DuToit et al, 2009).…”

Analyses of oxyanion materials by prompt gamma activation analysis

“…Additionally, in many cases, the counteranions associated with the central elements in the materials can be of extreme importance in the compound's role as synthetic precursors for other materials where the original materials or compounds have really good advantages as starting materials. Beryllium nitrate, for example, can be used as a starting material for the synthesis of beryllium oxide, 1 which is used in an extremely wide variety of applications ranging from sophisticated electronic materials 2 to dopants in gemstones 3 to dental materials. 4 It also represents, however, an element whose toxicity in humans 5,6 makes it extremely important as an analytical target due to many applications that impact both humans and the environment.…”