| FRIDRICHOVÁ, Jana, Peter BAČÍK, Petra RUSINOVÁ, Peter ANTAL, Radek ŠKODA, Valeria BIZOVSKA and Marcel MIGLIERINI. Optical and crystal-chemical changes in aquamarines and yellow beryls from Thanh Hoa province, Vietnam induced by heat treatment. Physics and Chemistry of Minerals. NEW YORK: SPRINGER, 2015, vol. 42, No 4, p. 287-302. ISSN 0342-1791. Available from: https://dx.doi.org/10.1007/s00269-014-0719-4. |
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@article{1340746,
author = {Fridrichová, Jana and Bačík, Peter and Rusinová, Petra and Antal, Peter and Škoda, Radek and Bizovska, Valeria and Miglierini, Marcel},
article_location = {NEW YORK},
article_number = {4},
doi = {http://dx.doi.org/10.1007/s00269-014-0719-4},
keywords = {Beryl; Heat treatment; Powder X-ray diffraction; Infrared spectroscopy; Mossbauer spectroscopy; Electron microprobe; UV/Vis/NIR spectroscopy; Raman spectroscopy},
language = {eng},
issn = {0342-1791},
journal = {Physics and Chemistry of Minerals},
title = {Optical and crystal-chemical changes in aquamarines and yellow beryls from Thanh Hoa province, Vietnam induced by heat treatment},
volume = {42},
year = {2015}
}
TY - JOUR
ID - 1340746
AU - Fridrichová, Jana - Bačík, Peter - Rusinová, Petra - Antal, Peter - Škoda, Radek - Bizovska, Valeria - Miglierini, Marcel
PY - 2015
TI - Optical and crystal-chemical changes in aquamarines and yellow beryls from Thanh Hoa province, Vietnam induced by heat treatment
JF - Physics and Chemistry of Minerals
VL - 42
IS - 4
SP - 287-302
EP - 287-302
PB - SPRINGER
SN - 03421791
KW - Beryl
KW - Heat treatment
KW - Powder X-ray diffraction
KW - Infrared spectroscopy
KW - Mossbauer spectroscopy
KW - Electron microprobe
KW - UV/Vis/NIR spectroscopy
KW - Raman spectroscopy
N2 - Optical and crystal-chemical changes in two beryl varieties after the heat treatment were determined using a wide spectrum of analytical methods. Studied aquamarines are generally more enriched in Fe (up to 0.25 apfu) and alkali (up to 0.08 apfu) than yellow beryls (up to 0.07 apfu Fe, up to 0.04 apfu alkali). The determined c/a ratio of 0.997-0.998 classified all our studied beryls as "normal" beryls. While no crystal structure changes were observed in samples heated to 700 A degrees C, those heated to 900 and 1,100 A degrees C exhibited cracks and fissures. Reduced Fe occurred in samples heated between 300 and 700 A degrees C, and subsequent oxidation from 900 to 1,100 A degrees C induced changes in their colour and clarity. The Fe-bearing beryl colour is controlled by the position of the absorption edge and the presence of a broad band attributed to Fe2+ in the NIR region. Blue colour results from the absorption edge located deeper in the UV region and the presence of broad band in the NIR region. Shift of absorption edge to the visible region at the presence of the broad band gives a yellow colour. Although our studied beryls are enriched in H2O I molecule due to their low alkali content, the H2O II molecule is also present. The following two dehydration processes were observed: (1) release of one double-coordinating H2O II molecule at 300-500 A degrees C and (2) total dehydration at 900-1,100 A degrees C. The observed cracks and fissures likely resulted from channel water release in large beryl crystals.
ER -
FRIDRICHOVÁ, Jana, Peter BAČÍK, Petra RUSINOVÁ, Peter ANTAL, Radek ŠKODA, Valeria BIZOVSKA and Marcel MIGLIERINI. Optical and crystal-chemical changes in aquamarines and yellow beryls from Thanh Hoa province, Vietnam induced by heat treatment. \textit{Physics and Chemistry of Minerals}. NEW YORK: SPRINGER, 2015, vol.~42, No~4, p.~287-302. ISSN~0342-1791. Available from: https://dx.doi.org/10.1007/s00269-014-0719-4.
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