Volume 22, Number 1, January - March 2004

Volume 22, Number 1  
  • Topaz from Killiecrankie, Flinders Island, and other Bass Strait Islands
  • Culturing Abalone Half-pearls
  • Agates & Geodes from the Khur Area, Central Iran
  • Amino Acids in the Nacre Layers of Shell from Magnavicula penguin and Blister Pearls from Sanya, China
  • Pink Gem Quality Orthoclase from the Mogok Stone Tract, Myanmar
  • Sapphire-blue Kyanite from Nepal

(Follow this link for abstracts of past issues)

TOPAZ FROM KILLIECRANKIE, FLINDERS ISLAND, 
AND OTHER BASS STRAIT ISLANDS 

R.S. Bottrill1, R.N. Woolley1, A.B. Forsyth2 
1Mineral Resources Tasmania, Rosny Park, Tasmania, 7018 
2P.O. Box 20 Albert Street, Brisbane, Qld, 4002.

ABSTRACT
Colourless to pale coloured gem topaz crystals, locally known as Killiecrankie diamonds, have been recovered in some abundance from Killiecrankie Bay, Flinders Island, since at least 1803. They are probably some of the earliest gemstones recorded and exported from Australia. The crystals derive from weathering of pegmatitic pockets within granite, but most are retrieved from alluvial deposits, some offshore. Similar topaz occurs on other parts of the island, and on Cape Barren Island.

CULTURING ABALONE HALF-PEARLS 
The story of the New Zealand Eyris Blue Pearl™ 

Pam Hutchins 
Wide Bay Valuation Services, Bundaberg

ABSTRACT
This paper provides information on the life history of the abalone, before describing the technologies and methods used by New Zealand based Eyris Pearls to culture and produce half-pearls from free diver harvested 'wild stock' of the New Zealand abalone, Haliotis iris or paua. Criteria used to grade the pearls are also illustrated and briefly described. 

AGATES & GEODES FROM THE KHUR AREA,
CENTRAL IRAN

Maziar Nazari 
Department of Earth Sciences, Ashtiyan Azad University, Iran

ABSTRACT
 The agates of Khur, Central Iran, are described together with the local topography, climate and geology of the Khur region. The agates have been examined using SEM with EDS and XRD techniques. It is proposed that the source of the silica for the agates is the prolonged hydrothermal activity in the area during the Eocene Epoch. The detection of evaporitic minerals suggests that a saline regime of ground water was, at least in part, a secondary process in the genesis of the Khur agates.

AMINO ACIDS IN THE NACRE LAYERS OF SHELL FROM MAGNAVICULA PENGUIN AND BLISTER PEARLS FROM SANYA, CHINA

Huang Fengming, Chen Zhonghui, Zhou Ying, Yang Mingxing
Gemmological Institute, China University of Geosciences, Wuhan, China

ABSTRACT
 Magnavicula or Peria penguin (Röding) is a large pearl-producing oyster, and is an excellent 'mother' animal for producing blister pearls. The authors of this paper determined the compositions and contents of amino acids in the nacre layers of shells of Magnavicula penguin and blister pearls produced by Magnavicula penguin from Sanya, China. For comparison purposes, we also determined the compositions and contents of amino acids in cultured freshwater pearls from Ezhou, Hubei, and cultured seawater pearls from Indonesia and Beihai, Guangxi, China. The experimental results showed that there are 17 amino acids found in the nacre layers of shells of Magnavicula penguin and blister pearls produced by Magnavicula penguin from Sanya. The main amino acids are, in an increasing order in content, glycine, alanine, aspartic acid, serine, arginine, and leucine or tyrosine. The concentrations of these amino acids account for more than 60% of the total concentrations of amino acids. Additionally, the total concentration of amino acids in blister pearls is higher than that in nacre layers of shells of Magnavicula penguin, and the concentration of amino acids in the nacre layer close to the hinge line is higher than that of amino acids in the nacre layer along the margin of the shells. Comparing cultured seawater and freshwater pearls, the nacre layer close to the hinge line contains a concentration of amino acids higher for that of cultured seawater pearls from Indonesia but lower than that of cultured seawater pearls from Beihai, Guangxi, and cultured freshwater pearls from Ezhou, Hubei. The nacre layer along the margin of the shells contains a concentration of amino acids lower than that of cultured seawater pearls but higher than that of cultured freshwater pearls; and blister pearls produced by Magnavicula penguin contain the highest concentration of amino acids in all tested samples.

PINK GEM QUALITY ORTHOCLASE
FROM THE MOGOK STONE TRACT, MYANMAR

U Hla Kyi1, U Kway Thu2
1Professor Emeritus, Department of Geology, Dagon University, Yangon, Myanmar
2Demonstrator, Department of geology, Yangon University, Myanmar

ABSTRACT
 A pink gemstone that was discovered as rough in the Mogok Stone Tract was studied and found to be facetable orthoclase feldspar, a potassium aluminium silicate gemstone that is very rare in Myanmar. The faceted orthoclase described in this paper is possibly the first find of this gemstone in Myanmar. In this paper the authors provide details of the physical properties and optical properties, XRD features and trace element analysis of this rare pink gemstone.

SAPPHIRE-BLUE KYANITE FROM NEPAL

Dr Ulrich Henn
German Gemmological Association, Idar-Oberstein

ABSTRACT
 Gem quality kyanite, of a deep sapphire-blue colour is described. This kyanite comes from a new occurrence in Nepal. The facetted stones investigated are of up to 12.2 ct in weight and possess the typical characteristics of blue gem kyanite.