Contributions to Gemology No.4 - Beryllium-Treatment
Adolf Peretti; Detlef Günther; Bernard Grobéty; Josef Mullis; Walter Oberholzer; Karl Ramseyer; Detlef Günther
Gemresearch Swisslab AG (2005)
In Collection
Corundum, Gemology, Gemstones, Synthetics/Treatments
Sapphires and rubies of different colors are routinely heat-treated to produce better clarity and color. As long as the treatment does not involve incorporation of color influencing trace elements - such as Ti, Fe and Cr - into the gemstones surface or irradiation, the trade generally accepts the enhanced gem materials as being valuable, depending on size, rarity and beauty.
In mid 2001, sapphires and rubies treated with a new method appeared on the market with dominantly orange-pink colors, which are commonly known in the trade as the "Padparadscha" colors. Natural Padparadschas are among the world's most requested, and rarest, gemstones, and therefore highly-priced. Depending on the exact nature of this new enhancement process, and hence the wording used to disclose and supply these sapphires to the market, the price of these materials may vary considerably. Early published reports initiated worldwide speculation on the nature of the treatment, ranging from pure heat treatment to a full blown diffusion treatment. The uncertainty about the exact nature of the treatment method, and therefore the lack of investor confidence, caused the worldwide market for the new sapphire materials to collapse (February - March 2002). Of particular interest to the trade is the question: "Are these new materials diffusion-treated?"
This volume is based on an earlier report of the presence of beryllium in these sapphires, and the occasional presence of color zoning confined to the sapphires' facets. A key factor to understand the color mechanism is the use of special analytical methods, such as UV-VIS-NIR (origin of color analyses), ED-XRF (e.g. Iron (Fe), Chromium (Cr) and Titanium (Ti) trace element analyses), SEM-EDS (chemical analyses of contaminated substances at the gemstones' surface), visual and spectroscopic cathodoluminescence investigations (analyses of internal growth structures), color-stability measurements (long-term color-stability to UV and visible light, and, most importantly, Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The LA-ICP-MS method - used to characterize the content and variation of all trace elements, including light elements such as Lithium (Li), Boron (B) and Beryllium (Be) on a micro scale - turned out to be the key factor in understanding the new heat treatment technique.
This report contributes to the understanding of the new heat treatment with Beryllium and to differentiate from conventional heat-enhancement (E) and conventional surface diffusion treatment (T).
Product Details
Series Contributions to Gemology
Issue No. 4
No. of Pages 65
Height x Width 295 x 210  mm
Personal Details
Read It Yes
Store Mineralogical Society of America
Location A 3
Purchase Price 40.00 CHF
Purchase Date mars 2013
Condition First hand
Links GemResearch Swisslab
Mineralogical Society of America