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Fibrous nanoinclusions in massive rose quartz: HRTEM and AEM investigations

Ma, Chi and Goreva, Julia S. and Rossman, George R. (2002) Fibrous nanoinclusions in massive rose quartz: HRTEM and AEM investigations. American Mineralogist, 87 (2-3). pp. 269-276. ISSN 0003-004X. https://resolver.caltech.edu/CaltechAUTHORS:20130417-073749432

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Abstract

Pink fibrous crystals within massive rose quartz from localities in California, South Dakota, Brazil, Madagascar, and Namibia were examined with high-resolution transmission electron microscopy (HRTEM) and analytical electron microscopy (AEM). This study reveals that the nanofibers in all samples are related to dumortierite. Selected-area electron diffraction (SAED) patterns and HRTEM images indicate that the dumortierite-related fibers have a superstructure with a doubled periodicity along the a and b axes of dumortierite, giving cell parameters a = 2a_(dum) = 2.36 nm, b = 2b_(dum) = 4.05 nm, c = c_(dum) = 0.47 nm. Computer simulations suggest that periodic arrangements of two different M1 site occupancies in the octahedral face-sharing chains give rise to the superstructure. One type of M1 site is occupied mainly by Al, whereas the other type is dominated by Ti and Fe. Simulated HRTEM images based on our proposed model match the experimental images. Most of the fibers, elongated along the c axis, are free of defects. AEM analysis shows that the dumortierite-related fibers have a composition similar to well-characterized dumortierite, but that they contain a greater amount of Fe substituting for Al in the M1 sites. Boron was detected in all fibers examined by electron energy loss spectroscopy as well as in sillimanite crystals found as a minor component in one rose quartz from Brazil.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://ammin.geoscienceworld.org/content/87/2-3/269.abstractPublisherUNSPECIFIED
ORCID:
AuthorORCID
Ma, Chi0000-0002-1828-7033
Rossman, George R.0000-0002-4571-6884
Additional Information:© 2002 American Mineralogist. Manuscript received April 4, 2001; Manuscript accepted November 12, 2001. Manuscript handled by Adrian J. Brearley. We thank Ulrich Dahmen and Christian Kisielowski for allowing us to access the ARM and the JEOL 200CX microscopes at the National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Roar Kilaas for helping with the NCEMSS image simulation program, Chengyu Song for assisting with the ARM operation, and Thomas George for allowing us to use the ISI 200 kV HRTEM at the Jet Propulsion Laboratory. Lothar Jung (Quartz Technology, Inc.) provided samples for this study and several stimulating discussions in the early stages of this project. Rock H. Currier (Jewel Tunnel Imports) and Edward Swobota (Beverly Hills, CA) also provided samples that were critical for this study. Careful reviews by Peter Heaney and Mike Zolensky led to a significant improvement in the quality of the manuscript. Primary funding for this project was provided by the White Rose Foundation with additional funding from the National Science Foundation through grant NSF EAR-9804871.
Funders:
Funding AgencyGrant Number
White Rose FoundationUNSPECIFIED
NSFEAR-9804871
Issue or Number:2-3
Record Number:CaltechAUTHORS:20130417-073749432
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130417-073749432
Official Citation:Chi Ma, Julia S. Goreva, and George R. Rossman Fibrous nanoinclusions in massive rose quartz: HRTEM and AEM investigations American Mineralogist, February-March, v. 87, p. 269-276
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37979
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:17 Apr 2013 19:30
Last Modified:09 Mar 2020 13:19

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