(Follow this link for abstracts of past issues)

Cultured freshwater pearls from the Yangtze River (China)

Magdelana Dumańska-Slowik, Wieslaw Heflik, Lucyna Natkaniec-Nowak, Magdalena Sikorska, Aleksandra Weselucha-Birczyńska

ABSTRACT Chinese freshwater tissue-graft pearls imitate natural pearls extremely well and may have their organic nucleation implants preserved to different extents. Except for the organic component, the cores of Chinese pearls are composed of mineral phases that are polymorphic modifications of calcium carbonate: i.e. aragonite or a mixture of aragonite, calcite and vaterite. It is supposed that these variously formed carbonates crystallized simultaneously until the atrophy of organic cells occurred. The external part of the pearls consists of aragonite with dark to light green `oscillatory' concentric layers of mother-of-pearl. The presence of these different mineral components in the pearls is corroborated by the occurrence of the bands observed in their Raman spectra: 1076, 1084, 1091 cm-1 (vl - aragonite/vaterite), 154 cm-1, 156 (T - calcite/aragonite), 935, 1086, 1087 cm-1 (vl - calcite/aragonite), 182, 208 em-1 (calcite/aragonite), 701 and 705 cm-1 (v4 - aragonite). The bands at 1123-1124, 2457, 3000 and 3076 cm-1 are attributed to organic substances. The bands at 1133, 1526 cm-1 typical of natural pearls were not recorded in the spectra of Chinese cultured pearls and their absence may therefore afford a means of discrimination between spontaneously nucleated natural pearls and these freshwater cultured Chinese pearls. Key-words: Chinese tissue-graft pearls, aragonite, calcite, vaterite, Raman mapping

The 4-sector 'hourglass' zoning in the centre of P2 pearl. NX.

Historical extracts from "The Gazetteer" of the Upper Burma
and the Shan States

As selected by Professor (Retired) of Geology, (Pin Long University) U.Tin Hlaing

ABSTRACT
A presentation of a series of extracts selected by Professor of Geology (Retired) U. Tin Hlaing from historical records and early Government reports, especially from
the Burma Gazetteer, concerning earlier days on the various Burmese gem fields. These extracts are not in any particular chronological order but contain comments and discussions of particular locations where certain gem minerals were found and when and in what sort of abundance and quality, as some measure of contrast to more recent experience and to disseminate the obscure information about early gem mining in Burma. The text has not been altered except to provide fluency of context and consistency of presentation with some explanatory
clarifications.

1. Burma Gazetteer
2. Mogok Township Council, 1998,
   information booklet.
3. M.Sc. thesis by Tin Hlaing, 1981.
4. Australian Gemmologist, Burmite, 1990,
   Volume 20, No. 6, pages 250 to 253.

A photoessay on Tanzanian Star sunstone

Grant Pearson
Mt Waverley, Victoria, Australia

ABSTRACT A photoessay highlighting the aesthetic iridescent inclusions of oriented hematite that characterise a specimen of star sunstone from Tanzania. An aventurescent feldspar from Tanzania that has being marketed commercially as 'Masai sunstone' provides the gemmologist-photographer with an interesting palette of attractive images. This short photoessay illustrates the cause of the apparent asterism of this sunstone and offers a selection of photomicrographs of its guest inclusions for appreciation by gemmologists.

Note from the laboratory - Anglesite - An unusual collector's gemstone

Gagan Choudhary, FGA and Chaman Golecha, FGA

Gem Testing Laboratory, Jaipur, India

ABSTRACT
Laboratory testing of an unidentified gem mineral.

Note from the laboratory - Yttria-stabilized Zirconia
Hemisphere apparently imitating a "Mabe" pearl

Taijin Lu, Ph.D., Yusuke Mizukami, G.G., Kazuyoshi Yasunaga, G.G., Tatsuya Odaki, G.G., and Hajime Uesugi, G.G.

ABSTRACT
A white half-sphere apparently imitating a "mabe" pearl was found in a Tokyo mineral
market. Characterization confirmed that it was polycrystalline yttria-stabilized zirconia.