Naslov
Determination of polytypism in zincohoegbomite by combining EMPA and X-ray determination

Autori
Bermanec, Vladimir ; Kniewald, Goran ; Tudja, Marijan ; Šoufek, Marin

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Electron microscopy, Simposium H, Vol III / Yacaman - Cancun : ICEM, 1998

Skup
14th International Congres on Electron Microscopy

Mjesto i datum
Cancún, Meksiko, 31.08.1998. - 04.09.1998

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
zincohoegbomite; X-ray diffraction; electron microprobe analysis

Sažetak
A mineral with hexagonal morphological features has been determined in the metamorphic marble series near Nežilovo in Macedonia. It is closely intergrown with gahnite-end-member spinel and a brown mica mineral determined as phlogopite. The X-ray diffraction pattern does not correspond to any known mineral. Microprobe analyses at nine discrete points provided data on its chemical composition: Al2O3 52.99%, MgO 0.70%, ZnO 37.74%, FeO 5.41% and TiO2 3.27%. This chemical composition resembles that of zincohoegbomite found in Turkey, but has a considerably larger zinc content. This similarity in chemical composition and the different X-ray diffraction patterns indicate the possibility of polymorphic structures. However, determinations of the unit cell and space group (a=5.729(2)A and c=37.097(5)A; P63mc) speak in favor of polytypism and the crystal structure determination provides proof for a new polytype of zincohoegbomite-(16H).

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Kemija

POVEZANOST RADA