Percleveite-(Ce), Ferriallanite-(Ce)

~0.8 mm fragment of pink percleveite-(Ce) crystal into brownish-black tabular ferriallanite-(Ce) from apoeudialyte pseudomorphose. This is the single known crystal of the mineral from the locality. Usually percleveite form here rounded grains replaced by ferriallanite. Percleveite from this specimen has distinct dichroism very similar to one of stilwellite-(Ce), and stilwellite also has REE:Si ratio 1:1. So initially it was determined as stilwellite. But rocks of Khaldzan Buragtag massif are extremely unsaturated with boron. And stilwellite occurrence is very problematic here. I was very happy, when percleveite-(Ce) was discovered in Sweden some years later. I'd immediately recognize it in strange "stilwellite" from Khaldzan. Selfcollected in July of 1990. Pavel M. Kartashov collection and photo.


This photo has been shown 502 times

Photo added: 20th Mar 2008