We have the pleasure to announce to that former PD. Dr. J. Mullis, a GRS board of directors member since 2000, have been promoted on the 6th of November 2002 to become "Professor of Mineralogy" at the University of Basel (Switzerland).
Prof. Dr. J. Mullis has a long record of cooperation with Dr. A. Peretti (see list below). His knowledge in mineralogy is internationally acknowledged and he is considered a world expert in the field of "fluid inclusions".

Prof. Dr. J. Mullis is currently working with GRS on projects regarding fluid inclusions in Burmese rubies and sapphires through our Swiss research activities.

List of joint publications:

Peretti, A. Mullis, J., Kündig R. (1990): Die Kashmir Sapphire und ihr gelogisches Erinnerungsvermögen. Neue Zürcher Zeitung, 187, p. 59.

Peretti, A., Dubessy J., Mullis J., Frost B.R. and Trommsdorff V. (1992): Highly reducing conditions during Alpine metamorphism of the Malenco peridotite (Sondrio, Northern Italy) indicated by mineral paragenesis and H2 in fluid inclusions. Contributions to Mineralogy and Petrology, 112, pp. 329 - 340.

Peretti, A., Mullis J and Mouawad F. (1996): The role of fluorine in the formation of color zoning in rubies from Mong Hsu, Myanmar (Burma). Journal of Gemmology, Vol. 25, No. 1, pp.3-19.

Peretti, A., Mullis J., Mouawad F. and Guggenheim R. (1997): Inclusions in synthetic rubies and synthetic sapphires produced by hydrothermal methods (TAIRUS, Novosibirsk, Russia). Journal of Gemmology, Vol. 25, No. 5, pp. 149-157.

Peretti A. and Mullis J. (1997): Distinction of natural and synthetic rubies by fluid inclusion analyses. XIV Ecrofi, European Current Research on Fluid inclusions, Nancy, France, July, Abtracts, p. 264-265.

Natural faceted rubies of high quality are highly priced gemstones. Synthetic rubies of similar size and appearance are approximately 100-1000 times less expensive than the natural counterparts. Therefore, criterias for the distinction of the natural rubies from their synthetic counterparts are of highly commercial relevance. Fluid inclusions rubies imitating Burmese rubies, which are produced by hydrothermal methods, fluid inclusions are also presents.

Burmese rubies (Mong Hsu, Myanmar): Mong Hsu rubies are recently discovered about 200 miles SE of the classical ruby occurrence of Mogok, in the Shan State not far away from the Golden Triangle (Myanmar, Thailand, Laos). Today it is the major source of high quality rubies for the gem industry (Peretti etal., 1996.) In the rarely occurring primary deposits, the rubies are found in calcite-fuchsite-mica-dravite veins which are encountered in dolomite-marbles. Mong Hsu rubies (in the none heat-treated rough state) are characterized by a strong color zoning, namely by a black sapphire core (rich in traces of Cr, Fe and Ti) and a red ruby rim (Cr-rich). Fuchsite, dolomite, white mica and fluorite are found as solid inclusions in the Mong Hsu rubies. Fluid inclusions are frequently present, such as various populations of primary, pseudo-secondary and secondary fluid inclusions. At room temperature, three phases are present in the isolated fluid inclusion tubes, including a CO2-liquid, CO-rich multi-volatile vapor and one daughter mineral (diaspore). In all the different fluid inclusion populations, similar liquid/vapour ratios were found, showing that there had been initially a very homogeneous fluid. The heating runs showed that the volatile-rich fluid inclusions were homogenizing from the liquid and vapour phase to the liquid phase, between 24 and 31’C. Melting of CO2 at –61’C indicates possible contamination of CO2 by CH4 with one or more further component such as N2, H2S showing that the concentration of CO2 is greater or equal to 85 mol-% of the volatile part. Due to the chemical composition of the accompanying minerals (F-dravite and F-tremolite) and the presence of fluorite inclusions, HF may also be present as a component of the volatile part. Because of the presence and size of Al-hydroxides as daughter minerals in fluid inclusions, it was furthermore concluded, that minor contents of H2O, approximately 5-10 vol.-%, were originally present in the fluids. Similar CO2-rich fluid inclusions were also found in other rubies and sapphires from other occurrences (e.g. Kashmir sapphires).

Synthetic rubies (Hydrothermal products, Russia, Novosibirsk)): Synthetic rubies and sapphires are produced in Novosibirsk by hydrothermal methods in steel autoclaves at elevated temperatures and pressures. Faceted are marketed in Bangkok (Thailand0 through a joint venture between a Thai company and the Russian Academy of Science in Novosibirsk, called TAIRUS. Typical solid inclusions in these products are various types of copper-alloys. Besides these characteristics, three phase inclusions are found, particularly in the synthetic rubies imitating Burmese rubies. They are composed at room temperature of a liquid, a vapour and solid daughter mineral. Primary fluid inclusions are characterized by very large irregularly terminated tubes. Secondary fluid inclusion trails appear as isolated regular shaped tubes, which are very similar to those found in the natural counterparts. Difference populations of fluid inclusions were found. Heating and freezing measurements yield the following observations: - First melting of ice occurred between –12 and –13’C. Such fluids are interpreted as KCl-dominated fluids. First melting occurred in other populations at –22’C, which are interpreted as NaCl dominated fluids. The amount of dissolved KCl and NaCl is determined as 8 and 9wt-% respectively. Two different types of solid inclusions were found (type I and II). The melting of daughter mineral (II) at +51 +/- 1’C in the potassium-dominated fluid identifies the solid II minerals as KHCO. The solid II crystals of a decrepitated fluid inclusion was analyzed by SEM-ENDS-analyses which confirmed our conclusion. However, it also showed the additional presence of K-Al-cabonate with higher cation/anion ratio. In sodium dominated fluids the daughter minerals are interpreted as NaCO3 *1H2O and mixture if both cannot be excluded without direct chemical analyses. The solid I crystals, which were present in fluid inclusions at room temperature and which were not grown by repeated heating and freezing experiments within the fluid inclusions, were not transformed during the heating/freezing experiments. They are ansisotropic and are therefore interpreted as CaCO3. The fluid inclusions from all populations were homogenizing from the liquid and vapour to the liquid phase between 345 to 367C, which proves that the liquid phase is an aequous solution.

It is concluded that fluid in the natural and synthetic rubies produced by hydrothermal methods have completely different chemical compositions, with CO2-rich solutions in natural rubies and sapphires and H2O-rich solutions in synthetic counterparts.These fluids can be distinguished by heating and freezing experiments in the range between –10 C and +40C. In the vast majority of the cases, primary or early secondary fluid inclusions in natural rubies or sapphires will contain two CO2-rich phases between –10 and +31C and only one phase at temperature above 31 C. Such simple test requiring heating and freezing experiments between –10 and +40C are easily available to any gemmologist.

Peretti, A., Mullis, J. and Mouawad F. (1996): The role of fluorine in the formation of colour zoning in rubies from Mong Hsu, Myanmar (Burma). Journal of Gemology, 25,1 pp.3-19.

Peretti, A., Mullis, J. and Mouawad F. (1997): Scanning electron microscrope and fluid inclusion studies of synthetic rubies and sapphires produces by hydrothermal methods at TAIRUS (Novosibirsk, Russia), Journal of Gemology, submitted.