Water in opal – what can it tell us?

Thomas, P; Aldrige, L; Smallwood, A

Water in opal – what can it tell us?

Thomas, P

Aldrige, L Smallwood, A

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Publisher:: International Colored Gemstone Association
Publication Type:: Journal Article
Citation:: InColor Magazine, 2019, (41), pp. 62 - 69 (8)
Issue Date:: 2019

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Field	Value	Language
dc.contributor.author	Thomas, P https://orcid.org/0000-0001-6962-2121	en_US
dc.contributor.author	Aldrige, L	en_US
dc.contributor.author	Smallwood, A	en_US
dc.date.available	2018-12-20	en_US
dc.date.issued	2019	en_US
dc.identifier.citation	InColor Magazine, 2019, (41), pp. 62 - 69 (8)	en_US
dc.identifier.uri	http://hdl.handle.net/10453/131021
dc.description.abstract	Opal is a hydrous silica composed of predominantly silicon dioxide and water. The chemical composition of opal is normally described by the general formula SiO2.nH2O. The formula indicates that opal contains water and the value of ‘n’ is variable so the water content is variable and is known to range widely. Such a simple formula hides much of the important characteristics of how water is contained in opal and the variability in the water content and states of water is intricately involved in the formation of opal and may influence properties of the opal as a gemstone. The understanding of the states of water in opal is therefore of importance. The way in which the water is contained provides clues to the mechanisms of formation of opal. The water contained may also be used as a probe to help elucidate the complex microstructure beyond the sphere array structure in which precious opal, in particular, is described. This article will outline the types of water present in opal that displays play-of colour (POC) and how these types have been determined using chemical and physical laboratory characterisation techniques.	en_US
dc.publisher	International Colored Gemstone Association	en_US
dc.relation.ispartof	InColor Magazine	en_US
dc.title	Water in opal – what can it tell us?	en_US
dc.type	Journal Article
utslib.citation.volume	41	en_US
utslib.location.activity	USA	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 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.consider-herdc	false	en_US
pubs.issue	41	en_US
pubs.publication-status	Published	en_US

Abstract:

Opal is a hydrous silica composed of predominantly silicon dioxide and water. The chemical composition of opal is normally described by the general formula SiO2.nH2O. The formula indicates that opal contains water and the value of ‘n’ is variable so the water content is variable and is known to range widely. Such a simple formula hides much of the important characteristics of how water is contained in opal and the variability in the water content and states of water is intricately involved in the formation of opal and may influence properties of the opal as a gemstone. The understanding of the states of water in opal is therefore of importance. The way in which the water is contained provides clues to the mechanisms of formation of opal. The water contained may also be used as a probe to help elucidate the complex microstructure beyond the sphere array structure in which precious opal, in particular, is described. This article will outline the types of water present in opal that displays play-of colour (POC) and how these types have been determined using chemical and physical laboratory characterisation techniques.

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http://hdl.handle.net/10453/131021