Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Mineralogical Magazine Don't get GSW? Talk to your librarian.
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Mineralogical Magazine; October 2007; v. 71; no. 5; p. 553-569; DOI: 10.1180/minmag.2007.071.5.553
© 2007 Mineralogical Society of Great Britain and Ireland
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Majzlan, J.
Right arrow Articles by Michallik, R.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

The crystal structures, solid solutions and infrared spectra of copiapite-group minerals

J. Majzlan* and R. Michallik

Institute of Mineralogy and Geochemistry, Albert-Ludwig University of Freiburg, Albertstraße 23b, D-79104 Freiburg, Germany

* E-mail: Juraj.Majzlan{at}minpet.uni-freiburg.de

Copiapite is a mineral of iron- and sulphate-rich acidic environments and has a general formula AFe43+(SO4)6(OH)2(H2O)20, where A = Fe2+, 2/3Fe3+, 2/3Al3+, Mg, Zn. The structure is built by infinite tetrahedral-octahedral chains and isolated octahedrally coordinated A sites. Our synthetic and natural copiapite samples can be divided into two large groups based on the orientation of the structural fragments. One group comprises copiapite phases where A = Al3+, Fe2+ or Fe3+ and we designate it as the structural type AL. The other group consists of copiapite with A = Mg2+, Zn2+ or Ni2+ and this is the structural type MG. The solid-solution series between Fe3+ and Al3+ copiapite is continuous. The series between Mg2+-Al3+, Mg2+-Fe3+ and Mg2+-Al3+-Fe3+ copiapite are not continuous; the samples with intermediate compositions contain two copiapite phases, one of the type AL and one of the type MG. The series between Mg2+ and Zn2+ copiapite is continuous only at 25°C. At 75°C, the Zn-rich portion of this system crystallizes a copiapite-like phase whose structure may be a superstructure of copiapite. The series between Al-Fe2+ and Mg-Fe2+ copiapite are not continuous and show complex behaviour of the intermediate compositions.

KEYWORDS: copiapite, crystal structures, solid solutions, infrared spectra






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Mineralogical Society of Great Britain and Ireland