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Growth defects and growth marks in pegmatite beryls

E. Scandale, S. Lucchesi and G. Graziani
Growth defects and growth marks in pegmatite beryls
European Journal of Mineralogy (June 1990) 2 (3): 305-311

Abstract

Pegmatite beryl crystals are studied by X-ray topography methods, optical and scanning electron microscopy and electron microprobe analysis. Topographs show quite perfect crystals characterized by the absence of basal dislocations and by five growth stages. Minor element concentrations suggest that P-T variations occurred mainly during the first three growth stages, by contrast, the chemical evolution of the environment must also be taken into account for the last stages. The remarkable ondulatory extinction of one sample is related to superficial grooves caused by corrosion of dislocation bundles. The present observations, taken as a whole, indicate that structural defects in beryls from pegmatites are characteristic features of their particular growth environment and can therefore be considered as growth marks.


ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 2
Serial Issue: 3
Title: Growth defects and growth marks in pegmatite beryls
Affiliation: Univ. Bari, Dip. Geomineral., I-70124 Bari, Italy
Pages: 305-311
Published: 199006
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 17
Accession Number: 1993-008896
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
N42°19'60" - N44°19'60", E09°40'00" - E12°25'00"
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Geoline, Bundesanstalt fur Geowissenschaften und Rohstoffe, Hanover, Germany
Update Code: 1993
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