Portal de Periódicos da CAPES

Isokite, CaMg[FIPO4], from Senhora de Assuncao, Portugal: new find and new data

2005; E. Schweizerbart; Volume: 182; Issue: 1 Linguagem: Inglês

10.1127/0077-7757/2005/0035

2363-7161

Rupert Hochleitner, Karl Thomas Fehr,

earthquake and tectonic studies

Isokite, CaMg[FIPO4], from a newly discovered occurrence in the pegmatite of Senhora de Assuncao, Portugal, is described. In contradiction to previous descriptions (DEANS et al. 1955, FISHER 1957, DEANS 1958) the newly found isokite does not form whitish earthy crusts but massive brownish or greyish masses and veins in contact to triplite. Paragenesis and age relations show that Assuncao isokite grows at the expense of earlier formed triplite. The FTIR spectrum of isokite is presented for the first time (observed bands at 456, 475, 564, 594, 649, 952, 1005, 1039, 1075, 1124 cm-1), chemical and X-ray diffraction data are given (a = 6.527 ± 0.005 A, b = 8.744 ± 0.005 A, c = 7.501 ± 0.006 A and β = 121.34 ± 0.009°) and the formation of isokite in pegmatites is discussed.