Volume 19, Number 1, January-March, 1995

A BRIEF ACCOUNT OF MYANMAR'S PEARL CULTURE INDUSTRY
Tint Tun
Yangon, Myanmar

ABSTRACT
The history of Myanmar’s pearl culture industry is now 40 years old. It is significant that for three decades the whole operation of pearl cultivation - from fishing, through seeding to harvest - has been carried out by Myanmar citizens. In accord with Myanmar's established market economy system, interest of local and foreign companies in pearl cultivation in Myanmar is encouraged.

THE RAMAN MICROPROBE: A new gemmological tool
Professor B. Lasnier
Gemmological Laboratory, University of Nantes

ABSTRACT
In this brief paper the author introduces gemmologists to the Raman microprobe p a non-destructive spectroscopic technique that is becoming more frequently used to identify inclusions deeply buried within faceted and rough gemstones, synthetics
made materials of gemmological interest.

JEMETER™ DIGITAL 90
T. Linton, A. Shields, B. Neville.
GAA Instrument Evaluation Committee 

ABSTRACT
An Instrument Evaluation Committee report on the Saratosa Instruments Division of Tensor Corporation’s Jemeter Digital 90 reflectometer.

HOW TO FOSSICK IN QUEENSLAND
A GUIDE TO NEW FOSSICKING LEGISLATION
B. Neville
Department of Minerals and Energy, Brisbane, Qld.

ABSTRACT
The new Queensland Fossicking Act came into force on 1 February 1995, to simplify tourist and recreational fossicking for minerals, gemstones and] ornamental stones throughout the state. It replaces the limited Mining (Fossicking) Act 1985, which applied only to certain declared areas, and provides a simple administrative frame-work clearly separate from that for commercial mining which is administered under the Mineral Resources Act 1989. Access to fossicking localities state-wide is now possible with the permission of land owners. The Act also provides for the continuation of Designated Fossicking Land and Fossicking Areas, where fossicking is possible without land owner permission, and introduces needed controls on camping in some of these.

The following notes set out the essential provisions of the new legislation.

AN EXAMINATION OF SWAROGREEN
A new imitation emerald from Austria
E. Fritsch, R.C. Kammerling, J.I. Koivula
Gemological Institute of America, Santa Monica, California, USA

ABSTRACT
This article reports on the gemmological characteristics of Swarogem™, a new glass emerald imitation from Austria.

A NEW VARIETY OF GROSSULAR GARNET WITH EXTENDED GEMMOLOGICAL CONSTANTS
R. Brightman
Canberra Institute of technology, Canberra
J. Tunzi
Kyneton, Victoria

ABSTRACT
A new source of grossular garnet, allegedly from an unknown locality in Mali, West Africa, has provided gemmy rough in a range of colours including dark brown, orangy brown, light yellowish brown, yellowish green, light peridot-green, olive-green, and intense bluish green. The material displays an absorption spectrum similar to that of andradite garnet and extends values of refractive index significantly above those previously recorded in the literature.

GEMS AROUND AUSTRALIA - PART 10
H. Bracewell
Mitchelton, Queensland

ABSTRACT
In this segment of the Bracewell’s travels around Australia. in search of gemstones, the Marra Mamba tiger eye deposit is described and its attractive ornamentals illustrated.

ALEXANDRITE CHRYSOBERYL SURPRISES
Alan Hodgkinson,
Portencross, Scotland

ABSTRACT
In this paper some alexandrite chrysoberyl surprises are offered for consideration by gemmologists who are interested in both the variations in properties and definition of boundaries for varieties of gemstones.

NICHOLAS CREATED ALEXANDRITE
G. Brown, S.M.B. Kelly
Brisbane

ABSTRACT
In this Study Club report the identifying properties and characteristic inclusions of crystal-pulled Nicholas Created AlexandriteÔ are presented.

THE CATHODOLUMINESCENCE OF SYNTHETIC PERICLASE
J. Ponahlo
Department of Mineralogy, Museum of Natural History, Vienna

ABSTRACT
Three colourless, one rosé tinted, and one brownish yellow specimen of synthetic
periclase from Australia and USA have been investigated by means of a cold-cathode
cathocloluminescence device, Cathodoluminescence spectra were recorded with a computer-assisted microspectrophotometric unit with a range of 380 - 950 nm., These spectra revealed luminescent bands which could be assigned to impurity ions and/or defect centres.

The blue cathodoluminescence of one colourless synthetic periclase of USA manufacture was caused by Ni²+ ions replacing Mg²+ ions in octahedral configu ration. The other colourless USA periclase, and all crimson cathodoluminescent specimens from Australia, also displayed blue luminescing surface cracks that owed their blue cathodoluminescence to point defects and dislocations in their periclase lattice. The brownish to yellowish red or crimson cathodoluminescence of synthetic periclase of Australian manufacture most probably originated from Mn⁴+ ions.

These findings are supported by recorded cathodoluminescent spectra, by data from trace analyses furnished by a new nondestructive EDPXRF method that uses polarised X-rays, and by the previously published literature.

It is hoped that this detailed description of cathodolunilnescence of these five specimens of synthetic periclase will serve as an introduction to a better understanding of the possibilities and manyfold applications that cathodoluminescence has for the solution of gemmological problems associated with natural and synthetic gemstones

Volume 19, Number 2, April-June, 1995

NEW EXTENSION OF MONG HSU RUBY DEPOSIT
U Tin Hlaing
Department of Geology, Taunggyi University, Myanmar

ABSTRACT
Description of an extension of the Mong Hsu ruby deposit some 10 km to the north.

BRIEF HISTORY OF HEAT
Richard W. Hughes
Boulder, Colorado, USA

ABSTRACT
The following is an excerpt from the author's upcoming book, Ruby,& Sapphire. It gives a brief history of corundum heat treatment, from ancient times up until the appearance of heat treated Sri Lankan geuda sapphires in the late 1970s. While there are specific reports mentioning corundum heat treatment dating back almost 1000 years, these involved low temperatures. High temperature heat treatment of corundum is largely a product of the 20th century, and was probably discovered during experiments on the reconstructed ruby known as the ‘Geneva ruby’. Heat treatment of Anakie sapphire to improve clarity was reported as early as 1916.

HEAT TREATING SAPPHIRES FROM THE ANAKIE DISTRICT, AUSTRALIA
Ted Themelis
Gemlab Inc., Torrance, California, USA

ABSTRACT
Systematic heat treatment of sapphires from the Anakie District, Queensland, Australia, was used to study the effects of heat on colour and clarity and to determine heat treatment parameters for maximising enhancement potentiality. About four kilos of rough, mixed-quality sapphires from the Anakie District were cleaned, classified, and heat-treated using different parameters under controlled atmospheric conditions. Heat treatment experiments showed that. regardless of the atmosphere used ‘silk’ may be partially dissolved by 1400°C, and fully dissolved from 1650°C upwards. Clearing the ‘silk’ increases the transparency of these sapphires, thus increasing their value. Heat treating green to yellow sapphires did not produce sapphires with significant market value. Blue to green stones produced better results. Selected, nearly colourless, silky, and brownish-spotted sapphires produced the best results. Careful control of heating and cooling rates can prevent cracking. The specimens were heated, by type and by batch, with sapphires heated by type yielding slightly better results than the sapphires heated by batch.

GEMMOLOGICAL MISCELLANY
G. Brown
ALLGEM Services, Brisbane

ABSTRACT
This miscellany of laboratory reports has been compiled from various short reports submitted for publication in The Australian Gemmologist.

HANNEMAN-HODGKINSON SYNTHETIC EMERALD FILTER`
T. Linton. A. Shields
GAA Instrument Evaluation Committeee

ABSTRACT
The Chelsea filter is a much used gemmological dichromatic filter that was originally devised by Anderson and Payne in 1934 at the Gem testing Laboratory of the London Chamber of Commerce The filter was devised with the collaboration of gemmology students of the Chelsea College of Science and Technology. As this filter allowed transmission of both deep red wavelengths around 690 nm and yellow-green wavelengths, around 570 nm, that matched emerald’s emission and absorption characteristics, it was initially recommended to assist the discrimination between natural emerald and its simulants such as green glass. Tourmaline, peridot etc. This discrimination was possib1e because chromium-containing iron- and vanadium free emeralds emitted a red fluorescence when illuminated by white light that had a content of ultraviolet wavelengths.

Synthetic emeralds were commercially introduced around 1940. These produced the same pink-red response as some emeralds through the Chelsea filter. However, although this filter was unable to predictable discriminate between natural and synthetic emerald, it was subsequently found capable of distinguishing aquamarine, blue topaz and their blue synthetic spinel simulants, for unlike natural gemstones blue cobalt-containing synthetic spinel emitted a red fluorescence under white light.

Almost sixty years later, William Hanneman and Alan Hodgkinson are now marketing the Hannemann-Hodgkinson Synthetic Emerald Filte, the purpose of which is “to help the gemologist make the important differentiation between natural and synthetic emeralds. The manufacturer, Hannenman Gemological Instruments, further emphatically states that the filter “is designed to be used in conjunction with and not in place of the Chelsea filter”.

VISUAL CHARACTERISTICS OF HEAT TREATED CORUNDUM
B. Sechos 
Gem Studies, Sydney

ABSTRACT
Heat treatment of corundum may change the colour and the clarity of many stones, and has been accepted as part of the gem trade. Changes in the appearance of the inclusions, and in some cases the reaction to ultraviolet light, can be used as an indicator of heat treatment in corundum. These changes are readily observed using normal microscope techniques, Also, the diffusion treatment of sapphire can be readily recognised using microscope techniques and a suitable immersion liquid. The internal characteristics of corundum, treated by the above methods, have been photographically recorded to illustrate this paper.

Volume 19, Number 3, July-September 1995

50th JUBILEE ISSUE

This issue contained the following papers of historical interest with respect to The Gemmological Association of Australia.

• INTRODUCTION

• HISTORY OF THE G.A.A. - G.A. Tombs

• HISTORY OF THE G.AA (NSW DIVISION) - G.A. Tombs

• GEMSTONES OF NEW SOUTH WALES - R.R. Coenraads

• HISTORY OF THE G.A.A. (VIC. DIVISION) - W.E. Funston

• GEMSTONES OF VICTORIA - T. Troiani

• HISTORY OF THE G.A.A. (QLD DIVISION) - D.G. Sanderson

• GEMSTONES OF QUEENSLAND - A.F. Wilson

• HISTORY OF THE G.A.A. (SA DIVISION) – A. Hill

• GEMSTONES OF SOUTH-AUSTRALIA – I.J. Townsend

• HISTORY QF THE G.A.A. (WA DIVISION) - B. Taylor, F. Parker

• GEMSTONES OF WESTERN AUSTRALIA - F. Parker

• HISTORY OF THE G.A.A. (TAS. DIVISION) - T.C. Roper, P. Walker

• GEMSTONES OF TASMANIA - B. Sweeney

• PEARLS OF AUSTRALIA - D. O'Sullivan, D. Cropp, O. Bunter

• HISTORY OF THE AUSTRALIAN GEMMOLOGIST - G. Brown

• EPILOGUE - Editorial Management Committee

Volume 19, Number 4, October-December. 1995

GEMS AND GEMMOLOGY IN SRI LANKA: THE EARLY HISTORY
M. M. M. Mahroof
Colombo, Sri Lanka

ABSTRACT
Sri Lanka, or Ceylon as the country was known until recent times, has been a treasury of gemstones from earliest times. For centuries writers and visitors to this island nation have confirmed that virtually all types of known terrestrial gems are found in Sri Lanka.

Ceylonese gemstones served many purposes in the ancient world. Importantly, they were significant articles of commerce as well as being essential adjuncts of royal authority and aristocratic status. Hence, the ancient Kings of Ceylon used sumptuary laws to control both the acquisition and use of gemstones. Consequently the official entrusted with the control of gemming was always a close associate of the King. Gemstones, being symbols of royalty, were helpful in asserting authority when disputations were brought before the throne. Hence, Ceylonese royalty underpinned the gem trade of ancient Ceylon.

The art of lapidary, which is intrinsic to both gem enhancement and the gem trade, developed rapidly in Ceylon. However, security considerations positively constrained intricate jewellery making. Thus gemstones, gem-craft and the gem trade are fascinating facets of the ancient and medieval history of Ceylon.

AMETHYSTS AND THEIR OCCURRENCES
H. Bank
German Gemmological Association
C. Milisenda
German Foundation for Gemstone Research

ABSTRACT
Amethyst is an ancient gemstone that occurs in several quite distinctive geological settings around the world. In this paper the major commercial deposits of amethyst in South America, North America, Africa and Europe will be described.

NOTES FROM A SINGAPOREAN LABORATORY
Tay Thye Sun 
Far East Gemological Laboratory, Singapore

ABSTRACT
The following brief reports discuss a selection of interesting gem materials that have passed through a south-east Asian gem testing laboratory.

GEMS AROUND AUSTRAUA - PART 11
H. Bracewell
Mitchelton, Queensland

ABSTRACT
In Part 11 of the Bracewell’s gemstone seeking travels around Australia the products of Western Australia's Wyloo amethyst deposit are described.

THE HAZARDOUS EFFFECTS OF REFRACTOMETER CONTACT FLUlD
A NOTE
T.Linton
G.A.A. Instrument Evaluation Committee

ABSTRACT 
While investigating the current availability of high refractive index liquids, that gemmologists commonly use as refractometer contact fluids, the Committee discovered several reasons why the long used Anderson and Payne refractometer fluid – a saturated solution of sulphur and tetraiodoethylene in di-iodomethane that has a refractive index of 1.81 has been removed from the European market

A HISTORY OF PIETRE DURE
T. Troiani
Mellourne, Victoria

ABSTRACT
In the 16th century, a mosaic art form using gemstones and ornamental stones
developed By the Opificio delle Pietre Dure – now the National Museum in Florence, Italy. Pietre dure was originally used to beautify altars and the interior of chapels, but progressed to include reproductions of oil paintings. Soon this mosaic art form was adapted to produce jewellery that ranged from necklaces to brooches and entire suites of jewellery.

The art of pietre dure is, at the present time, experiencing a new Renaissance; with works of art being designed, manufactured and exhibited not only in Florence, but in the USA, Australia and New Zealand.

AN EXAMINATION OF PERIDOT FROM ETHIOPIA
R.C. Kammerling, J.I. Koivula 
GIA Gem Trade Laboratory, Santa Monica, California, U.S.

ABSTRACT
Peridot has been found in basaltic 'bombs' scattered on a desert plain near the villages of Mega and Magado in the southern part of Ethiopia. This article focuses on the gemmological properties of the peridot from this new locality.

Volume 19, Number 5, January-March, 1996

SHAPE, STRUCTURE AND COLOURS OF POLYNESIAN PEARLS
J.-R Cuif, Y. Dauphin, C. Stoppa, S. Beeck
France

ABSTRACT
This paper will briefly discuss the processes that determine both the quality and
colour of the nacre of the black-lipped pearl oyster, Pinctada margaritifera - the pearl oyster of French Polynesia.

WARIERITE
A NEW BLACK TOURMALINITE GEMSTONE FROM WESTERN AUSTRALIA
J. G. Olliver
Olliver Geological Services Ply Ltd, McLaren Vale SA
M. Thompson 
Murray Thompson Lapidary, Adelaide

ABSTRACT
Fine grained massive black tourmaline marketed as warrierite has formed within a major fault zone by metasomatic replacement of Archean volcanic rocks subsequently intruded and brecciated by white quartz veins. Warrierite contains ferrous iron and magnesium and is therefore midway in chemical composition between dravite and schorl. Warrierite is hard, tough, durable and produces a superb polish owing to the interlocking mesh of minute tourmaline crystals. Two distinct lapidary materials: black essentially pure tourmaline (warrierite), and an associated mottled black and white tourmaline-quartz rock, are ideal for carving and provide new world class gem material for Australia.

AGATE CREEK AGATE
Paul Howard
Elanora, Queensland

ABSTRACT
At Agate Creek in North Queensland attractively patterned agates occur in and are weathered from amygdaloidal basalt of Carboniferous age. Agate Creek agates are renowned both for the beauty and diversity of their attractive colour patterns. In this paper, the aesthetic features of polished agates from this deposit of possible world significance will be illustrated.

AUSTRALIAN (1.81) REFRACTOMETER FLUID
Trevor Linton, Barry Neville
G.A.A. Instrument Evaluation Committee

ABSTRACT
For the past two years many Australian gemmologists have been compelled to use Refractive Index (R1) fluid with a refractive index of 1.79, instead of the long-used RI fluid that had a refractive index of 1.81. Over that period of time the Instrument Evaluation Committee received many complaints concerning the instability of this refractometer fluid, particularly when the ambient temperature dropped below 20°C.
With the recent marketing of a (1.81) RI fluid, manufactured in Australia to the original Anderson and Payne formulation, a higher refractive index fluid once more is available for use in routine gemmological testing. However, users of this fluid are reminded of precautions essential for the safe use of this potentially toxic fluid.

1994 GEMSTONE PRODUCTION IN THE NORTHERN TERRITORY
NT Department of Mines & Energy

ABSTRACT
Tabulation of mines, and their locations that produced gemstones and gem materials in the Northern Territory during 1994.

DYED OPALISED SANDSTONE AND CONGLOMERATE
A NEW GEM PRODUCT FROM ANDAMOOKA
J. L. Keeling, I. J. Townsend
Mines and Energy, South Australia

ABSTRACT
A new technique has been developed at Andamooka to darken the body colour and enhance the play of colour in natural sandstone and sandy conglomerate cemented by precious opal. Samples displaying attractive colours and patterns are being produced in sizes suitable for carving and in various thickness slabs for opal doublets, inlay work, or tiles. Abundant fine-grained quartz sand-clasts, and patches of carbon in pore spaces and around the margin of quartz grains, are visible using low power magnification. These features make this gemstone readily identifiable from other types of opal.

REVIEW OF DIAMOND RESOURCES IN SOUTH AUSTRALIA
I.J. Townsend, B.J. Morris, M.G. Farrand
MESA, Parkside, South Australia

ABSTRACT
Diamonds were first found in South Australia at the Echunga Goldfield by gold
panners in 1859. Reports of 50 saleable diamonds and possibly up to 200 diamonds
are recorded through to 1900. Since then one diamond of reasonable size (0.9 ct) has been found at National Dam, Echunga, in 1987. 

A second occurrence is the Springfield Basin where 128 diamonds and fragments were recovered from basal conglomerates of Permian age underlying Triassic Carbonaceous sediments.

A third locality is at Eurelia where 140 microdiamonds were recovered from a cluster of kimberlites. These are the only proven diamond source rocks so far found in South Australia.

Numerous occurrences of one to several diamonds have been recorded throughout the state, and a number of zones with anomalous kimberlitic indicator minerals have been defined. Extensive state-wide detailed aeromagnetic surveys during 1992-94 have recently increased the diamond exploration tempo in South Australia.

Volume 19, Number 6, April-June, 1996

THE STATUS OF PEARL CULTURE IN INDONESIA
T. Winanto, K. Mintardjo
Seafarming Development Centre, Teluk Betung, Indonesia

ABSTRACT
Indonesia is an emerging producer of those bead nucleated saltwater cultured pearls that have been popularly termed South Sea pearls. In this paper areas suitable for pearl culture are located, and methods used to produce these pearls will be described. An assessment of Indonesia's future role as a pearl producer also will be made.

THE BAILEY LIGHT SOURCE
T. Linton, R. Beattie, G. Brown
Instrument Evaluation Committee, Brisbane

ABSTRACT
An evaluation of a South Australian manufactured refractometer light source that uses Stanley high brightness 5000 series LEDs to illuminate the scale of either Topcon or Rayner refractometers.

GEMS AROUND AUSTRALIA- PART 12
Hylda Bracewell
Mitchelton, Queensland

ABSTRACT
The search for gemstones took us to many other places in Australia that were very much off the tourist track. Getting to several of the fossicking areas required many hours of travel on kilometres of dirt roads and tracks. Part 12 takes the gem seekers to one such area – Yinnietharra and Mt Philip Stations, in a remote part of Western Australia.

AN EXAMINATION OF COLOUR-CHANGE SAPPHIRES FROM TANZANIA
R. C. Kammerling, M. L. Johnson
GIA Gem Trade Laboratory, Santa Monica, California, U.S.A.
Y. Liu
GIA Research, Santa Monica, California, U.S.A.

ABSTRACT
Many sapphires from a new discovery in southern Tanzania show a change-of-colour or ‘alexandrite effect. Eleven sapphires between 1.06 and 2.16 ct were examined. These had yellowish brown, greyish violet, and greyish greenish blue body colours under daylight-equivalent fluorescent light, and purple colours under incandescent light. All of the stones examined were strongly zoned in colour. Qualitative chemical analysis showed that these sapphires contained trace Fe, Cr, and Ti; with V in one stone and Ga in another. The changes in colour with illuminant for these sapphires were determined quantitatively. Nine of the eleven sapphires had changes in hue angle of greater than 20 degrees between daylight and incandescent light, like that of alexandrite chrysoberyl.

GEMMOLOGICAL MISCELLANY
G.Brown
ALLGEM Services, Brisbane

ABSTRACT
This miscellany of laboratory reports have been compiled from various short reports that have been submitted for publication in The Australian gemmologist.

INTERESTING GEMS FROM NORTH-EAST TASMANIA
Boyd Sweeney FGAA
South Hobart, Tasmania

ABSTRACT
In this paper the author describes and illustrates those gemstones that are recovered by fossickers in north-east Tasmania. Although rare, and of largely academic interest, these gemstones indicate that Tasmania could have potential as a future producer of gemstones.

MONG HSAK RHODOLITE GARNET 
U Tin Hlaing
Department of Geology, Taunggyi University, Myanmar
Tin Tin Win
Division of Exploration and Mining, CSIRO, North Ryde, Sydney

ABSTRACT
Gem quality rhodolite garnet has been recovered from the alluvial gravels of the Shan State's Mong Hsak River since 1993. In describing this new Myanmar gem garnet, the authors have provided information about the occurrence, gemmological properties, and chemical composition of this garnet.

NOTES FROM THE MUSEUM
G. Webb 
Mineral Section, Australian Museum, Sydney

ABSTRACT
In this note ruby and colour-changing sapphires from the Gloucester Tops area of NSW are described for the first time.

Volume 19, Number 7, July-August, 1996

ELECTRUM IN ANTIQUITY:
WHY WAS ONE WORD USED FOR TWO SUBSTANCES?
John Saul
Paris, France

ABSTRACT
In antiquity the word electrum was used, at different times, to describe two different materials - amber and an alloy of gold and silver. The author traces the origin of this dichotomy in terminology through mythology, the influence of the Zodiac, and ancient history.

ZONING IN SRI LANKAN ZIRCONS: CHEMICALLY CONTROLLED?
M.S. Rupasinghe
Institute of Fundamental Studies, Kandy, Sri Lanka
A. Senaratile
Department of Geology, University of Peradeniya, Peradeniva, Sri Lanka

ABSTRACT
The variation of trace element composition in some zoned zircons from Sri Lanka has been studied using the electron microscope and electron microprobe. Distribution of iron shows a marked correlation with both minor and major zones in the zircons. High iron concentrations, within zones, indicate a high rate of structural damage that results from isotropisation caused by high uranium (U) and thoriurn (Th) concentrations. In Sri Lankan zircon, iron migrates through pathways created by radiation damage. Further, the variation of U, Th and other trace element content, from nuclei to the surface, indicates the compositional variation of the
solutions involved in the formation of Sri Lankan zircon.

MEASUREMENT OF REFRACTIVE INDEX BY THE APPARENT DEPTH METHOD
Don Bennett 
Warradale, South Australia

ABSTRACT
The technique for determining the refractive index of a faceted gemstone, by the direct measurement apparent depth method, has been described in literature. Seldom has the accuracy of this technique been quantified. Consequently, experiments to determine the practicability and accuracv of this method of determining refractive index will be described in this paper.

THE TRUE STORY OF WHITE CLIFFS
G. Rowe
White Cliffs History Group

ABSTRACT
Using abstracts from the literature, the author has documented the origins and problems associated with the mining of opal from the historic Australian opal field of White Cliffs.

LAB NOTES
B. Sechos,
Gem Studies, Sydney
G. Brown
ALLGEM Services, Brisbane

ABSTRACT
Description of the gemmological properties and features of an intense violet-blue diamond from Australia’s Argyle diamond mine, and amber that was surface coloured by a new treatment.

ETHIOPIA: A NEW SOURCE FOR PRECIOUS OPAL
D. B. Hoover 
Arvada, Colorado, USA
Telahun Z. Yoliannes
Weatridge, Colorado, USA 
D. S. Collins
Arvada, Colorado, USA

ABSTRACT
A new source for precious opal has recently been discovered near the village of Mezezo, Shewa province, Ethiopia. The opal is found filling lithophysae in a Tertiary welded tuff unit lying hoizontally and extending for more than 15 kilometres. Claims have been filed on 2500 hectares covering the known opal-bearing area. About 1 per cent of the opal in the lithophysae has a play of colour, and much of the opal is crystal base. Refractive inclides (1. 439 to 1.448) and specific gravities (1.85 to 2.02) of the-opal are similar to that of other precious opal from volcanic sources. Long term stability to cracking and crazing is not well established, but is expected to be similar to that of other volcanic opals.

SCANNING ELECTRON MICROSCOPE STUDIES ON BLEACHING OF JADEITE
T. S. Tay
Far East Gemological Laboratory, Singapore
S.P. Liew., C,M. Puah
Chemical Process and Biotechnology Department, Singapore Polytechnic, Singapore

ABSTRACT
This study examined the effects of bleaching agents, such as plum juice, sodium hydroxide, and hydrochloric acid, on the surfaces of jadeite. After immersing various qualities of jadeite, for periods of up to ten days, plum juice was found to have the lease effect on grain structures. Hydrochloric acid most affected the grain boundaries, while sodium hydroxide required ten days immersion to affect noticeable changes in grain structures. It is anticipated that these observations could be used to assist gemmologists differentiate bleached from natural jadeite.

Volume 19, Number 8, October-December, 1996

COMBARBALITA: AN ORNAMENTAL KAOLINITE FROM COMBARBALA, CHILE
R. R. Coenraads
Sydney

ABSTRACT
This beautifully coloured and patterned ornamental clay material is formed through the deep kaolinitic weathering of a metamorphosed volcanic and sedimentary rock sequence. The name combarbalita owes its origin to the fact that the rock is unique to the region around the town of Combarbala, Chile. It is mined and worked locally.

The most useful characteristics of combarbalita are that it is soft enough to be either worked by hand or turned on the lathe; yet it is so coherent and rnassive that the material does not crack or fracture when extremely thin, fine, or delicate pieces are turned or worked When the rock contains trace amounts of copper the resulting blue or green combarbalita may be mistaken for turquoise.

While best quality artefacts, which have been hand-crafted from combarbalita, find their inspiration in the customs and lifestyles of the El Molle and Diaguita Indians, Hispanic influences, and the typical desert countryside of the region. These works of art are being replaced in the marketplace by, modern turned articles¾for mechanisation, in the form of lathes, has made these items cheaper and faster to produce.

THE EMPRESS PEARLÔ
A New Zealand cultured half-pearl
L. McKenzie
Christchurch, New Zealand

ABSTRACT
Half-pearls, cultured in New Zealand Hatiotis iris, are being marketed as Empress pearlsÔ. This paper describes the history, culture technology, and gemmological characteristics of these pearls.

THE TYPICAL GEMMOLOGICAL CHARACTERISTICS OF ARGYLE DIAMONDS
J. Chapman
Technical Development Department, Argyle Diamonds, Perth
G. Brown
ALLGEM Services, Brisbane
B, Sechos
Gem Studies, Sydney

ABSTRACT
Western Australia's Argyle lamproite pipe, the world's largest producer of diamond by volume, yields brown, yellowish brown, colourless and red to pink diamonds that have a dominantly eclogitic paragenesis. Fancy coloured type la Argyle diamonds typically have a low nitrogen content, rnostly in the B-aggregated form. These diamonds are highly strained, colour zoned parallel to (111), and mostly contain proto/syngenetic inclusions that reveal an eclogitic paragenesis. The typical gemmological characteristics of these diamonds have been tabulated for easy reference.

POLAROID Macro 5 SLR CAMERA
T. Linton,,S. Sultman
G.A.A. Instrument Evaluation Committee Report

ABSTRACT
For many years jewellers and gemmologists have had to overcome manv technical
problems associated with the production of immediate, accurate and permanent records of identifying external features of gemstones and jewellery. The Polaroid Corporation has solved most of these problems with the recent release of its Macro 5 SLR instant camera system.

CRYSTAL CARVING AND OTHER ESOTERIC THINGS
F. H. Thrupp
Moonee Ponds, Victoria

ABSTRACT
A brief review of the role and influence carvings in rock crystal have had throughout the ages.

NORTHERN TERRITORY FOSSICKING LEGISLATION
T. Roberts
Department of Mines & Energy, Darwin

ABSTRACT
Fossicking regulations with respect to the Northern Territory are described, before designated fossicking areas within the Territory are located and described.

Volume 19, Number 9, January-March, 1997

EPR/ESR SPECTRA OF NATURAL AND SYNTHETIC OPALS
A Pilot Study
D.R. Hutton, G.J. Troup 
Physics Department, Monash University, Melbourne
M. Young
South Oakleigh, Victoria

ABSTRACT
Electron Spin Resonance spectra of opal have been determined for the first time. Observed differences in these spectra should allow discrimination between natural Australian opal, opal from other world-wide sources, and ‘synthetic’ as represented by early production Gilson opal™.

A short description of this research has been presented previously in Australia to the Australian and New Zealand Institute of Physics Condensed Matter Physics meeting, in Wagga Wagga, New South Wales, that was held from 30th January to 2nd February 1996. 

TASMANIA AND ANTARCTICA: A LONG ASSOCIATION
P. G. Quilty
ANARE Chief Scientist, Australian Antarctic Division, Tasmania

ABSTRACT
Tasmania and Antarctica were united in Gondwana from at least 600 million years ago until Australia and Antarctica finally separated about 55 million years ago. Initially they, were in equatorial regions, but moved to the south polar area some 350 million years ago. Antarctica has been there ever since.

For much of the time in the south polar regions, both areas were subject to the same rock forming environments including the Permian with its Gondwana wide glacial episodes interspersed with intervals of coal formation. Tasmania has marine and non-marine components, whereas Antarctica was totally, non-marine at the time. The following Triassic sediments in both Antarctica and Tasmania, which are wholIv non-marine, consist of lake and riverine sandstone, coal and shale. Permian and Triassic sediments were intruded at 170 million years (mid Jurassic) by massive dolerite, 350 metres thick, in one of the world’s unique events which may have been caused by the first stress related to eventual dispersal of the continental units that constituted Gondwana. This event did not extend to mainland Australia.

At 55 million years, Australia began to move north from Antarctica at about 7 cm per year. At the same time. Tasmania underwent fracturing into horst and graben structures that still control Tasmania's landscape. Also at this time, the Antarctic Circumpolar Current began to circulate around the Antarctic, leading to the eventual isolation of that continent, development of an ice sheet, and the extinction of the flora and fauna which, until that time, had been common to both Antarctica and Australia. The modern cold temperate rainforests of Tasmania are a relic of the flora that was once common to both landmasses.

Tasmania’s rocks, landforms, solid and vegetation are all the result of a common history with Antarctica, which Tasmania carried out with it as it moved north from its long term partner.

ABALONE PEARLS FROM BASS STRAIT
Derek Cropp
Mount Nelson, Tasmania

ABSTRACT
Both in Australia, and overseas, the edible flesh of the abalone is highly valued. Tasmania is Australia’s largest supplier of this very succulent shellfish. Over recent years an increasing interest has been shown in rare, mostly baroque natural abalone pearls. This demand had resulted in asking prices that often exceed those demanded for traditional cultured pearls. As a consequence of the increasing demand for abalone pearls, and an expectation that round to baroque cultured abalone pearls would maintain their value more consistently than half-pearls, research by a Tasmanian company has been directed towards refining aspects of the commercial culture of whole pearls. While the technology for cultivating these pearls is still being developed, results to date suggest a significant commercial industry could become viable within a few years. Demand for cultured abalone pearls, particularly the rarer varieties, is expected to outstrip their supply for many years to come.

AN OCCURRENCE OF GEM QUALITY DIOPSIDE, YINNIETHARRA STATION, WESTERN AUSTRALIA
Frank Doedens
Wilson, Western Australia

ABSTRACT
In this report, the occurrence and gemmological properties of gem quality diopside, found in a deposit on Yinnietharra Station, Western Australia is described. Approximately 100 carats of faceted diopside were produced from rough recovered from this deposit. Three specimens were used to determine the gemmological properties of this mineral.

IDENTIFYING CHARACTERISTICS OF HYDROTHERMAL SYNTHETICS
B. Sechos 
Gem Studies Laboratory, Sydney

ABSTRACT
In this paper the identifying properties, features and characteristic inclusions of those hydrothermally produced synthetic emeralds and rubies, that are presently readily available in the Australian market, are described and illustrated.

FOSSICKING IN QUEENSLAND
Queensland Department of Mines & Energy

ABSTRACT
Fossicking regulations with respect to Queensland are described, before designated fossicking areas within Queensland are located and described.

Volume 19, Number 10, April-June, 1997

THE PEARL FISHERIES OF SRI LANKA
Some chapters from a forgotten history
M.M.M. Mahroof
Colombo, Sri Lanka

ABSTRACT
For several millennia, Ceylon, which became the Republic of Sri Lanka in 1972, was famous for its natural pearl fishery, Historically, pearls were both commercial luxuries and royal gems. Indigenous kings controlled pearling until 1505, after which time Ceylon was ruled by a succession of Portuguese, Dutch, and British administrations. As the gains from pearling were highly profitable, but erratic, in the early part of the 20th century the British Government of Ceylon tried to encourage scientific cultivation of the pearl oyster in the seas off the Mannar coast.This strategy quickly led to the weakening, and eventual final collapse of the historic Ceylonese natural pearl fishery.

FIBRE TORCHES
B. Neville
GAA Instrument Evaluation Committee, Brisbane

ABSTRACT
A gemmological association of Australia Instrument Evaluation Committee report on fibre torches manufactured by the Australian gemmological equipment manufacturer, Linton Enterprises.

ARGYLE DIAMONDYPINK DIAMOND TENDERS
(1985 -1996)
Polished Sales Division, Argyle Diamonds, Perth

ABSTRACT
Argyle Diamonds has been marketing the Argyle diamond mine's most valuable pink diamonds by a tender process that has been operative since 1985. In this paper the history, and romance behind this now well established annual event has been described.

YTTRIUM ALUMINIUM PEROYSKITE
Trevor Linton 
Wellington Point, Queensland

ABSTRACT
Attractive pink or orange stones, manufactured in Russia by crystal pulling, are presently being marketed in the USA under the name Yttrium Aluminium Perovskite or YAP. Gemmological testing has revealed that this material is an imitation, for its properties do not match the hardness (5½), specific gravity (4.0) and mean refractive index (2.38) of the mineral perovskite.

THE MERLIN PROSPECT
Australia's next commercial diamond mine?
Ashton Mining Limited, Melbourne

ABSTRACT
Diamondiferous kimberlite pipes in the Northern Territory's Merlin Prospect could be the site of Australia’s next commercial diamond mine, as early as the first quarter of 1998. Four pipes (Excalibur. Launfal, Palomides. and Sacramore) are presently the subject of final feasibility and engineering design studies. 

THE RED PEARLS OF PINNA NOBILIS
J.-P. Gauthier, J. Caseiro, B. Lasnier
France

ABSTRACT
Pinna nobilis, the noble pen shell of the Mediterranean Sea is a rare source of natural pearls. As the valved of the Pinna nobilis are lines bu both aragonitoic and calcitic nacre this bivalve is capable of secreting two distinct types of pearls¾red calcitic pearls and creamy aragonitic pearls. In this paper the characteristics of both types of natural pearl are described and illustrated.

NEW EMERALD DEPOSITS FROM SOUTHERN INDIA
J. Panjikar, K. T. Ramchandran, K. Balu
Gemmological Institute of India, Bombay

ABSTRACT
In the mid 1990s, emeralds were discovered embedded in the wall of a well at the village of Sankari Taluka, in southern India’s state of Tamil Nadu. Gemmological research into the chemistry, properties and characteristic inclusions of these emeralds has revealed similarities between the properties of Sankari emerald and those of emerald from several previously described locations on the island of Madagascar. This finding suggests that Sankari emeralds may have been emplaced into the ancient supercontinent of Gondwanaland before India rifted from it some 200 million years ago.

Volume 19, Number 11, July-August, 1997

THE DIAMOND DEPOSITS OF MYANMAR
U Tin Hlaing, 
Geology Department, Taunggyi University, Myanmar
Tin Tin Win
CSIRO, North Ryde, NSW

ABSTRACT
In Myanmar, alluvial diamonds occur at three localities: Theindaw, Toungoo, and Momick, This paper describes the occurrence of these diamonds, their mineral associations, and the general features of diamonds from each deposit.

THE GEM KIT
T. Linton, S. Sultman, J. Peters
G.A.A. instrument Evaluation Committee 

ABSTRACT
Marketing cased portable gem testing equipments is not a new concept. In the past, few portable gem testing kits have been truly compact, as those incorporating all necessary equipment have required a porter's trolley, to facilitate transportation. In response to the practical limitations inherent in the design of compact gem testing kits, suitable for use by travelling gemmologists and gem merchants, Mr N Masson of NM Australia Pty Ltd has developed a well-thought-through NM Gemmological Instruments Gem Kit for use by valuers, gemmologists, gem merchants, and students of gemmology.

ORIGIN AND FORMATION OF AGATE-BEARING SPHERULITES:
THE THURINGIAIN FOREST, GERMANY
G. Holzhey
Geological Survey of Thuringia, Germany

ABSTRACT
The origin of agate-bearing spherulites from the Lower Permian rhyolites of the Thuringian Forest, Germany, was investigated. These rhyolitic spherulites, which had star-shaped central cavities containing agate and quartz, are located within marginal facies of volcanic domes and lava flows. The zone containing the largest spherulites represents areas of a highly viscous, vapour-laden chilled melt which degassed and devitrified by the growth of spherulites.

Hydrogen-metasomatic alteration of the rhyolites, within the marginal facies, was caused by their interaction with telethermal to epithermal solutions of meteoric origin. As a result, the host rock surrounding the spherulites was enriched with alteration minerals such as illite. Silica mobilised as a result of metasomatism diffused to form agate in the central cavities of the spherulites. The processes of mobilisation, accumulation. and redeposition typify agate genesis at temperatures mostly below 100 ºC. The different microstructures and other features of the Thuringian agates confirm the previous gel-like phase of epigenetic silica mineralisation that formed Forest agate.

ALEXANDRITE CHRYSOBERYL FROM DOWERIN, WESTERN AUSTRALIA: REVISITED
A. Bevan, P. Downes 
Department of Earth and Planetary Sciences, Western Australian Museum

ABSTRACT
One of only four recorded occurrences of alexandrite chrysoberyl in Australia occurs near Dowerin, Western Australia. Known since 1930, the deposit was the first recorded in Australia and has yielded many small alexandrite crystals. Recent re-working of the deposit has allowed further examination of the gem-bearing rocks and a preliminary report is given here.

INCLUSIONS IN AGATES AND CHALCEDONIES
Paul Howard
Elanora, Queensland

ABSTRACT
A selection of aesthetic inclusions that have been photographed by the author from polished agates from Agate Creek, North Queensland.

GEMS AROUND AUSTRALIA - PART 13
H. Bracewell
Mitchelton, Queensland

ABSTRACT
Our journey around Australia continues through Western Australia, and in this part we take in some sightseeing as well as our fossicking,

GEMMOLOGICAL FEATURES OF RUBIES AND SAPPHIRES FROM
THE BARRINGTON VOLCANO, EASTERN AUSTRALIA
Gayle Webb
Mineral Section, Australian Museum, Sydney

ABSTRACT
Ruby is unusual in Australia, but in the Barrington area of New South Wales ruby and pink sapphire can form.150 per cent of the weight of sampled gem corundum concentrate. Two distinct suites of sapphire accompany the rubies: one related to the ruby, the other is typical of eastern Australian sapphires. Both suites were brought up in basaltic volcanic eruptions. In this paper the gemmological features of these rubies and sapphires are described. Crystalline aggregates of corundum, sapphirine and spinel appear to be xenolithic remnants of the rubies’ parent rock. Recent data has revealed that the corundum suite containing ruby, originated in a metamorphic environment, while the other suite had a magmatic origin. 

Volume 19, Number 12, October-December, 1997

A NEW ERA FOR OPAL NOMENCLATURE
Anthony Smallwood
Chairman, G.A.A. Opal Nomenclature Sub-committee

ABSTRACT
Opal is a relatively common mineral species that is found in many locations world wide. For many years a reason for the spectacular phenomenon known as play-of-colour, as seen in precious opal, remained a well-hidden secret. It was not until the 1960s that Australian scientists, working at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) used a new Instrument now known as the electron microscope to reveal the inner structure of opal and how this is responsible for generating the play-of-colour of precious opal.

Opal often was referred to as a ‘semi-precious gemstone’, until unique Australian black opal was discovered and successfully marketed. Today, all varieties of precious opal, which are mined in the Australian states of New South Wales, South Australia and Queensland, support a $A500 million per year industry.

One problem that the opal industry has been required to face, however, is how does one describe a gemstone that occurs both with and without a play-of-colour, in almost every colour of the rainbow, in every tone of lightness and darkness from black to white, and in every degree of transparency from opaque to perfectly, transparent. Also, this unique gemstone displays differences in mineralogy that reflect the varying geological environments in which it forms. 

The opal nomenclature that follows is a result of three years of striving within Australia’s opal industry to achieve co-operation, and to formulate a nomenclature for opal that is accepted uniformly throughout the industry.

PEARLS AND PEARL OYSTERS IN THE GULF OF CALIFORNIA, MEXICO
D. McLaurin, E. Arimendi , S. Farell, M, Nava
I.T.E.S.M-Perlas de Guaymas, Mexico

ABSTRACT
For more than four centuries, pearl fisheries in the Gulf of California were the main supply of natural coloured pearls to the world; until overfishing caused these pearls to disappear. The world's first commercial pearl oyster culture venture was established at La Paz, South Baja California, for the production of mother-of-pearl shell and natural pearls. Unfortunately, this pearl farm was destroyed by the Revolutionary Army in 1914. In 1996, after more than four years of research, I.T.E.S.M-Perlas de Guaymas was established as a pilot-scale commercial venture for culturing the native pearl oysters, Pteria sterna and Pinctada mazatlctizica, and their pearls. The farm's technology is based on the suspended culture system, the use of commercially-manufactured hanging culture equipment, and the use of Mexican grafting technology that was developed at I.T.E.S.M. This one-of-a-kind pearl farm is located at Bacochibampo Bay, Guaynias, Sonora, Mexico. It employs twelve people to culture some 150,000 pearl oysters from both species to produce, this year, around 30,000 mabé pearls and some round pearls. It would appear that pearls are returning to the Gulf of California.

A MISCELLANY OF ORGANICS
G.Brown
Albany Creek, Queensland

ABSTRACT
T his miscellany has been compiled from interesting laboratory reports that the author has prepared over the last decade. Although the emphasis of this miscellany is on identifying features of some of the rarer organics; some little emphasised yet simple observations, that can be used to identify the commoner organics, also have been described and illustrated.

CORUNDUM (RUBY) FROM THE KAREN STATE, MYANMAR: A NOTE
U Tin Hlaing
Geology Department, Taunggyi University, Myaninar

ABSTRACT
This note describes the location, occurrence, and basic gemmological features of a newly discovered source of ruby in the Shan State, Myanmar. The ruby, though not of gem quality, may be prospective for a new source of gem quality Burmese ruby.

A NEW TECHNIQUE FOR DETECTING SYNTHETIC YELLOW SAPPHIRE
T. Linton
Wellington Point, Queensland

ABSTRACT
Synthetic yellow sapphire, grown by Verneuil flame-fusion technology and coloured by nickel (Ni³+) and chromium (Cr³+), produces an identifiable fluorescence which may be observed following irradiation with ultra-violet wavelengths, with a gemmological spectroscope, or through a red band-pass filter.

Careful rapid cooling of flame-fusion synthetic yellow sapphires produces a fluorescent line in the red of this sapphire’s visible absorption spectrum that is not normally seen in light coloured yellow sapphire. This fluorescence also is visible following long- and short-wave ultraviolet irradiation, as well as when a red band-pass filter is used to examine the yellow sapphire as it is illuminated by visible white light.

Efficient use of these tests requires careful control of viewing conditions following the sapphire’s cooling to the temperature of liquid nitrogen.

MEIJI TECHNICO MODEL GF-252 REFRACTOMETER-POLARISCOPE
T. Linton, S. Sultman, G. Peters
GAA Instrument Evaluation Committee

ABSTRACT
First-used gem testing instruments should provide fundamental information for the 
gemmologist. The usefulness of this information depends on the gemmologist‘s sound knowledge of of gem testing procedures, use of instruments that provide rnaximum useful information, and ease of access to that information. Three instruments, such as the hand lens, refractometer and polariscope, should provide all the information required to assign a gemstone to its mineral variety.

With two of the first-used gem testing instruments being built into the one instrument an economy of scale must occur This observation is supported by the cost of the Meiji Technico GF-252 refractometer-polariscope that has been valuated in this report.

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