Welcome to AGTA GTC's Laboratory Update for March 29, 2006

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  1. Beryllium-Treated Blue Sapphires

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Beryllium-Treated Blue Sapphires

In November of 2005, Bangkok's GRS announced that they had detected significant amounts of beryllium (Be) in a number of blue sapphires (Peretti et. al., 2005). The possibility of using beryllium to lighten overly dark blue sapphires was first demonstrated by John Emmett and Troy Douthit in experiments run in December 2002–January 2003 (Emmett et al., 2003).

Be treated sapphires

Figure 1. Group of six sapphires suspected to be treated with beryllium. [note: these were later checked by LA-ICP-MS and found to contain no measurable beryllium]
Image: Min Htut/©AGTA GTC

    At the 2006 AGTA GemFair Tucson, a number of discussions were had on the subject of beryllium in blue sapphire. These consultations were followed by a meeting in Bangkok on March 2, 2006, attended by the AGTA GTC's Garry Du Toit. A further meeting was held on March 23, 2006 in New York, where GIA staff made a presentation to a number of colored gemstone dealers. The AGTA GTC's Lore Kiefert, Garry Du Toit and Riccardo Befi were in attendance.
    Initial discussions suggested two distinct possibilities with regard to the beryllium recently detected in blue sapphires:

  • Either the detected beryllium entered the gemstones via accidental contamination from treatment in furnaces previously used with beryllium treatment, or…
  • Beryllium was added deliberately (probably with an eye towards lightening the color of overly dark blue sapphires).

Getting specific
To help address the question of accidental versus deliberate beryllium diffusion, the GIA recently tested a parcel of 56 suspect blue sapphires provided by Vincent Pardieu of Bangkok's Asian Institute of Gemological Sciences (Pardieu, 2006). Testing was performed by LA-ICP-MS, calibrated with element-in-sapphire standards, including beryllium.
    Beryllium was found in every piece; many showed substantial amounts. In addition to the GRS and the GIA, tests at Japan's GAAJ have also revealed beryllium in blue sapphire, as early as 2003 and 2004. In all cases, the levels found were high enough that they would seem to preclude accidental contamination.

To Be (or not to Be)
The current evidence suggests this is no accident. Indeed, at the Bangkok meeting, one burner described to attendees the deliberate addition of beryllium in treating blue sapphires.
    Sophisticated treatments are a fact of life. Even though this treatment appears to be in its infancy, stones have entered the world market. As a result, the policy of the AGTA GTC from now on will be that all corundums showing signs of long-term/high-temperature heat treatment will require advanced testing before beryllium diffusion can be ruled out. The comment on our report will read as follows:

Enhancement: Indications of heating1
Comments: 1Further advanced analysis is required to determine whether or
  not a foreign element has been introduced.

    With the commercial appearance of beryllium-diffused blue sapphires, we can expect a further acceleration of the trend towards sapphires that have had no heat treatment whatsoever.

Moving forward
Previously hurt by the introduction of beryllium-diffused fancy sapphires and rubies in 2001–2002, the world's gemstone trade has since reacted to the appearance of new treatments with a quick, firm hand. When lead-glass filling of Madagascar ruby hit the market in 2004, many Thailand-based dealers encouraged labs to clearly label these goods, lest they spoil the market. And as the latest story of Be-treated blue sapphires has spread, we have seen a similar proactive approach by dealers in Bangkok, Chanthaburi and elsewhere.
    The AGTA GTC is working closely with sapphire dealers and gemologists around the world to prevent this latest treatment from adversely impacting the market. Towards this end, the AGTA GTC is in the process of acquiring a LIBS (Laser-Induced Breakdown Spectroscopy; aka LIPS: Laser-Induced Plasma Spectroscopy) unit. This will allow in-house detection of beryllium in corundum down to a few parts per million. We will continually strive to stay at the forefront of gemology, ready to deal with whatever challenges the future might bring.

Further reading

  • Emmett, J.L. and Douthit, T.R. (1993) Heat treating the sapphires of Rock Creek, Montana. Gems & Gemology, Vol. 29, No. 4, Winter, pp. 250–272.
  • Emmett, J.L. and Douthit, T.R. (2002). Beryllium diffusion coloration of sapphire:
    A summary of ongoing experiments
    . AGTA GTC, posted September 4.
  • Emmett, J.L., Scarratt, K., McClure, S.F., Moses, T., Douthit, T.R., Hughes, R., Novak, S., Shigley, J.E., Wuyi Wang, Bordelon, O., Kane, R.E. (2003) Beryllium diffusion of ruby and sapphire. Gems & Gemology, Vol. 39, No. 2, Summer, pp. 84–135.
  • Hughes, R.W. (2002) The skin game. Ruby-Sapphire.com, posted Feb. 2002.
  • Hughes, R.W. (2004) LIBS – A new beryllium testing method. Palagems.com, posted April 29, 2004. <http://palagems.com/beryllium_libs_testing.htm>
  • Larson, W.F. (2004) Gods, graves and sapphires. Palagems.com, posted March 2004.
  • Pardieu, V. (2006) Understanding blue sapphire heat treatment:
    Introduction to the beryllium issue
    . Asian Institute of Gemological Sciences, posted March 1. <http://www.aigslaboratory.com/aigsbeblue.php>
  • Peretti, A., Günther, D. et al. (2005) Beryllium-treatment. Contributions to Gemology, No. 4, December, pp. 1–65.
  • Schmetzer, K. and Schwarz, D. (2004) The causes of colour in untreated, heat-treated and diffusion-treated orange and pinkish-orange sapphires - a review. Journal of Gemmology, Vol. 29, No. 3, pp. 149–182.
  • Schmetzer, K. and Schwarz, D. (2005) A microscopy-based screening system to identify natural and treated sapphires in the yellow to reddish-orange colour range. Journal of Gemmology, Vol. 29, No. 7/8, pp. 407–449.

Postscript: Identifying Be-treated blue sapphires
In December 2005, a number of inclusion photos of Be-treated sapphires were published (Peretti & Günther et al., 2005). The photos in question can be viewed online at these links:

    The caption to these photos (C18–C22) states:

"Circular, curved and white lines associated to former zones of silk. Magnification 50-100x in the microscope. Fibre optic illumination. This inclusion have sofar [sic] only been detected in Beryllium-Treated blue sapphires."

crop circle inclusions

Figure 2. Circular inclusions in a heat-treated blue sapphire, approximately 70x. Image: R.W. Hughes/©AGTA GTC

    There are two theories regarding these irregular inclusions (such as that in Figure 2). One holds that they are unique to this treatment and might possibly result from exsolution of beryllium. But as Figure 3 (below) shows, we have seen such inclusions in gemstones for well over a decade, long before the advent of beryllium heating. Thus such features would seem to indicate only high-temperature heating, rather than specifically beryllium diffusion.

Circles in Sapphire

Figure 3. Inclusions in a heat-treated blue sapphire. What is remarkable is that this photo was shot more than a decade ago, long before the advent of beryllium diffusion. This suggests that such inclusions do not necessarily indicate beryllium lattice diffusion, but simply high-temperature heat treatment. Image: © John I. Koivula/microWorld of Gems

    It is also possible that these circular inclusions are merely the remnants (skeletons, if you will) of thin films of rutile or other minerals following high-temperature heat treatment. Witness the similarity of these skeletons to the thin films in the unheated sapphire shown in Figures 4 and 5. It may be that the heating draws material into solution, leaving a skeleton behind. Attempts are now underway to analyze these inclusions in hopes of discovering their exact nature. The more we observe these inclusions, the more we lean towards their being some type of precipitate generated during heat treatment.

thin films

Figure 4. Circular thin film inclusions in an untreated blue sapphire, seen scattered throughout clouds of intact rutile silk, approximately 30x. Image: R.W. Hughes/©AGTA GTC

Thin films in an untreated sapphire

Figure 5. The same circular thin film inclusions as Figure 4, more highly magnified, approximately 70x. Image: R.W. Hughes/©AGTA GTC

    So how would we go about identifying Be-treated blue sapphires? With the exception of the yellow color rims (which are not found in the Be-treated blues), the same way we identify Be-treated corundums in other colors.

  1. The first step is to look for signs of long-term/high-temperature heat treatment (altered inclusions, unusual fluorescence, changes in the FTIR spectra, etc.).
  2. Any gemstone that shows signs of major (long-term/high-temperature) heat treatment will require advanced testing with SIMS, LA-ICP-MS or LIBS to determine if beryllium is present.

    In future articles we will discuss some of the features we use to spot long-term/high-temperature heat treatment.


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