Description | Gadolinite is a yttrium iron beryllium silicate that also contains significant amounts of cerium, lanthanum, and neodynium. Its formula is (Ce,La,Nd,Y)2FeBe2Si2O10. This sample is black and vitreous, but some gadolinite has a green or blue color. Gadolinite occurs in alkalic pegmatites and granites. This sample, from Hitterbo, Norway, is about 5 cm across. |