CHARACTERIZATION OF
A NEW CHINESE HYDROTHERMALLY GROWN EMERALD

Chen Zhenqiang¹, Zeng Jiliang² Cai Keqin^{3 1} Zitang Changlong², Zhou Weining²

¹Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian Province
²Gemological Institute of Guangxi, Guilin, Guangxi Province
³China University of Geosciences, Beijing.

ABSTRACT
The present study is a result of an examination of new hydrothermal synthetic emeralds recently produced in Guilin, Guangxi Province, P. R. China. A strong red reaction to the Chelsea colour filter, a moderate red long-wave ultraviolet fluorescence, a slightly bluish green colour, and a much lower chlorine and higher alkali element content are common diagnostic features of this new Chinese synthetic emerald. In addition, infrared spectral properties in the 3500 - 3800 cm^-1 region, and three strong peaks in the 5000 - 5500 cm^-1 region are useful to discriminate this new Chinese product from other hydrothermal emeralds, and their natural counterparts.

Tay Thye Sun
Far East Gemological Laboratory, Singapore

Based on a lecture presented to the APEC 2000 International Jewellery Conference,
Melbourne, Australia, 28-29 August 2000

ABSTRACT
It is a fact that the worldwide gemstone and jewellery industries are becoming increasingly aware of the importance of appropriate disclosure of the true nature of synthetics, value-enhanced gemstones and imitations to purchasers of these materials. In this paper the author uses treated jadeite as an example of a value-enhanced gemstone for which active attempts have and are being made to provide adequate disclosure for purchasers. The various jadeite treatments, termed A-, B-, C, and B+C-jade, are explained, and their identifying features discussed. While advanced instrumentation, such as FTIR, is generally considered essential for definitive detection of these treatments, the author offers some practical advice about some basic observations the trade gemmologist may use to recognize these treatments. Finally, a new categorization of jade treatment is proposed to cover those treated jades that have been bleached and then impregnated with moderate to significant amounts of wax-instead of polymer.

THE GEMSTONE OCCURRENCES OF MADAGASCAR

ABSTRACT
For a long time Madagascar has been known as a producer of gemstones. Beryls (particularly emerald and aquamarine), tourmalines, quartzes, garnets and feldspars are the commercially important gemstones from this island. Recently, sapphires also have increased in economic importance. This paper summarizes the large variety of gemstones, and their various occurrences in Madagascar.

ABSTRACT
Two interesting reports from Alan Hodgkinson’s Scottish Gem Lab. The first report described use of the Hanneman tanzanite filter and Visual optics to discriminate tanzanite from two of its look-alike imitations, synthetic forsterite, and glass. In the second report the Hanneman-Hodgkinson refractometer is used to determine the refractive indices, birefringence, dispersion and B/D ratio that identified so-called pink synthetic perovskite as orthorhomble yttrium aluminate.

ABSTRACT
Critical angle refractometer measurements of refractive index, birefringence, optic character, and optic sign are the basis of most coloured gemstone identification& Although this instrument can also measure dispersion, this paper illustrates the lack of utility of such a technique.

ABSTRACT
An occurrence of an ornamental variety of pink marble with apatite, abutting a large apatite deposit near Eppawala in Sri Lanka, is described. The deposit lies within the Wanni Complex which is one of the three major lithotectonic units found in Sri Lanka. Apatite bearing rock runs almost in the north-south direction, and most properties are comparable with those of the major apatite deposit at Eppawala. A variety of associated minerals including magnetite, spinel, pyrite, zircon etc. were also observed. The gemmological properties of the material are summarized, and the use of this marble as an ornamental product and a carving material is also documented. Chemical analysis, by means of X-ray fluorescence analysis, confirmed this to be a marble consisting of calcite.