Vanda Rolandi¹, Anna Brajkovic², Ilarla Adamo³, Rosangela Bocchio³,
Manuela Landonio²

¹Italian College of Gemmologists (CIG), External Collaborator at University of Bicocca, Italy
²Department of Geological Sciences and Geotechnologies, University of Milano Bicocca, Italy
³Department of Earth Sciences "Ardito Deslo*, University of Milano, Italy

ABSTRACT
Several gem corals, belonging to the classes Hydrozoa and Anthozoa of the phylum Cnidaria, have been analyzed. These have been previously classified from a zoological point of view. In this paper surface structures, physical data, FTIR- and Raman-spectra of corals with gem potential have been investigated. Spectrophotometric characterisation proved to be a useful tool for determining the main features of the mineral phases (calcite or aragonite) and of the organic content in each sample. Chromophore complexes belonging to the caroteno-proteins of the carotenoid family also could be detected.

THE PEGMATITIC GEM DEPOSITS OF MOLO (MOMEIK) AND SAKHAN-GYI (MOGOK)

Professor U Hla Kyi¹, Ted Themelis², U Kyaw Thu¹

¹Yangon, Myanmar
²Bangkok, Thailand

ABSTRACT
Molo, situated about 32 miles (51 km) northeast of Momeik in Myanmar's Shan State, is a new source of many rare gemstones and minerals including phenakite, petalite, hambergite, Cs-rich morganite and pollucite. At Molo, botryoidal-type tourmalines of various colour, aquamarine, topaz, quartz and Li-mica (lepidolite) also are found. These minerals and gemstones are mainly recovered from the alluvial sediments as well as in pegmatite dykes that are intruded into peridotite country rock (Kyaw, Khaing Win 2003).

The pegmatite deposit at Sakhan-gyi, which is situated about 10 miles (16 km) west of Mogok in the Mandalay Division, has been the main source of aquamarine, goshenite, topaz and quartz. Occasionally, scheelite and cassiterite are also encountered. The dyke is much kaolinized where orthoclase, cleavelandite, microcline, quartz, muscovite, topaz, aquamarine, goshenite and other minerals are found. The pegmatite dyke at Sakhan-gai is about 15 million years old and it is found intruding the Kabaing granite (about 16-20 Ma), (Searle and Haq 1964, Touret 2004 personal communication)

The types of pegmatites and the probable temperatures and pressures of their formation, their physical and optical properties, characteristic features, EDXRF results and selected mineral inclusions found in some of these gems are presented in this paper.

THE IDENTIFICATION OF IMPREGNATED NEPHRITE

Li Jianjun

Shandong Provincial Gold and Gem Testing Center (SDGG)

ABSTRACT
Asians treasure nephrites, especially white nephrite from Hetian in the Xinjiang province of China. Unfortunately the yield of the Hetian white nephrite is becoming less and less as the years pass by. As a result, ever increasing amounts of white nephrite from Russia and the Qinghai province in China have come onto the market at prices lower than those of Hetian white nephrite.

Recently, some white nephrites from Russia and Qinghai province, which have been bleached and impregnated to imitate Hetian white nephrite, have appeared in the marketplace. Who is treating and marketing these difficult to identify value-enhanced white nephrites is presently unknown.

Research has suggested that these treated nephrites can be positively identified by use of the infrared spectrometer. This method of identification will be described in this paper. As these treated nephrites are not acceptable under present international guidelines, when detected these treated nephrites must be disclosed.