Comparative analysis of sedimentary and volcanic precious opals from Australia

Smallwood, AG; Thomas, PS; Ray, AS

Comparative analysis of sedimentary and volcanic precious opals from Australia

Smallwood, AG Thomas, PS

Ray, AS

Permalink

Publication Type:: Journal Article
Citation:: Journal of the Australian Ceramic Society, 2008, 44 (2), pp. 17 - 22
Issue Date:: 2008-12-01

Open Access

Copyright Clearance Process

Recently Added
In Progress
Open Access

This item is open access.

Adobe PDF

Download full textAdobe PDF (355.98 kB)

View statistics

Full metadata record

Field	Value	Language
dc.contributor.author	Smallwood, AG	en_US
dc.contributor.author	Thomas, PS https://orcid.org/0000-0001-6962-2121	en_US
dc.contributor.author	Ray, AS	en_US
dc.date.issued	2008-12-01	en_US
dc.identifier.citation	Journal of the Australian Ceramic Society, 2008, 44 (2), pp. 17 - 22	en_US
dc.identifier.issn	0004-881X	en_US
dc.identifier.uri	http://hdl.handle.net/10453/9387
dc.description.abstract	Precious opal is Australia's national gemstone, with Australian opal fields providing 90% of world production. The sedimentary geological environment, associated with Cretaceous sediments of the Great Artesian Basin, is the source of most precious opals in Australia. The deposit of precious opal at Tintenbar in northern New South Wales is the only known commercial occurrence of precious opal in volcanic environment in Australia. Differences in silica structure of opal previously classified by x-ray diffraction (XRD) in the 1960's by Jones and Segnit identified three types of opal structure - amorphous opal-A, opal-CT with a poorly crystalline intergrowth cristobalite and tridymite and opal-C showing the cristobalite structure. Recent papers have suggested that all precious opal from a sedimentary environment is Opal-A, and all precious opal from the volcanic environment is opal-CT. This paper examines the differences between sedimentary precious opals from Coober Pedy, South Australia, and volcanic precious opal from Tintenbar, NSW using XRD, scanning electron microscopy and thermal analysis.	en_US
dc.relation.ispartof	Journal of the Australian Ceramic Society	en_US
dc.subject.classification	Materials	en_US
dc.title	Comparative analysis of sedimentary and volcanic precious opals from Australia	en_US
dc.type	Journal Article
utslib.citation.volume	2	en_US
utslib.citation.volume	44	en_US
utslib.for	0912 Materials Engineering	en_US
utslib.for	0303 Macromolecular and Materials Chemistry	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Civil and Environmental Engineering
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Mathematical and Physical Sciences
pubs.organisational-group	/University of Technology Sydney/Strength - CBI - Centre for Built Infrastructure
utslib.copyright.status	open_access
pubs.issue	2	en_US
pubs.publication-status	Published	en_US
pubs.volume	44	en_US

Abstract:

Precious opal is Australia's national gemstone, with Australian opal fields providing 90% of world production. The sedimentary geological environment, associated with Cretaceous sediments of the Great Artesian Basin, is the source of most precious opals in Australia. The deposit of precious opal at Tintenbar in northern New South Wales is the only known commercial occurrence of precious opal in volcanic environment in Australia. Differences in silica structure of opal previously classified by x-ray diffraction (XRD) in the 1960's by Jones and Segnit identified three types of opal structure - amorphous opal-A, opal-CT with a poorly crystalline intergrowth cristobalite and tridymite and opal-C showing the cristobalite structure. Recent papers have suggested that all precious opal from a sedimentary environment is Opal-A, and all precious opal from the volcanic environment is opal-CT. This paper examines the differences between sedimentary precious opals from Coober Pedy, South Australia, and volcanic precious opal from Tintenbar, NSW using XRD, scanning electron microscopy and thermal analysis.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/9387