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Influence of annealing on X-ray diffraction of natural alexandrite

Published online by Cambridge University Press:  05 March 2012

Rosa Maria Fernandes Scalvi ,
Lígia de Oliveira Ruggiero  and
Máximo Siu Li
Rosa Maria Fernandes Scalvi
Affiliation:
Departamento de Física, Faculdade de Cie⁁ncias-UNESP-C.P. 473, 17033-360-Bauru-SP
Lígia de Oliveira Ruggiero
Affiliation:
Departamento de Física, Faculdade de Cie⁁ncias-UNESP-C.P. 473, 17033-360-Bauru-SP
Máximo Siu Li
Affiliation:
DFCM-Instituto de Física de Sa˜o Carlos-USP-C.P. 369, 13560-970-Sa˜o Carlos-SP
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Abstract

In this work we present results of X-ray diffraction using powder method, on natural alexandrite samples from Minas Gerais State (Brazil), as a function of a sequence of annealing. From these measurements we determine lattice parameters before (a=9.405 Å, b=5.471 Å, c=4.409 Å) and after annealing, and its structure is confirmed as orthorhombic. Measurements done after an annealing of 15 minutes at 700 °C and for 5 hours at 1000 °C indicate the migration of atoms present in the sample through different phases, which were also identified by Microprobe Analysis (WDS). However we have verified that such migration does not modify the structure. X-ray diffraction measurements have been carried out in conjunction with optical absorption in the UV–Vis as a function of annealing.

Keywords

alexandriteoptical absorptionX-ray diffraction
Type
New Diffraction Data
Information
Powder Diffraction , Volume 17 , Issue 2 , June 2002 , pp. 135 - 138
Copyright
Copyright © Cambridge University Press 2005

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