To prepare the riebeckite-type rare earth ore for analysis, a composite sample of approximately 10 kg was crushed to ∼2 mm and then riffled to produce 5.0 kg batches. One batch was further riffled to yield representative sub-samples of approximately 100 g for chemical composition and mineral analysis. A 100 g sub-sample was then crushed into The rocks are fine-grained with equidimensional constituents averaging about Imm in diameter. With a lens glassy grains of quartz, cleavable feldspars, black prismatic crystals (riebeckite), usually small but sometimes 3mm in length, and minute greenish patches and needles (aegirite) can be recognized. The most common amphibole mineral by far is hornblende. Riebeckite is a sodic amphibole (rich in Na). It forms a solid solution series with another sodic amphibole glaucophane. The chemical formula of the glaucophane-riebeckite pair: Na 2 Mg 3 Al 2 Si 8 O 22 (OH) 2 (glaucophane) — Na 2 Fe 32+ Fe 23+ Si 8 O 22 (OH) 2 (riebeckite) Both of them |jfl| dis| rqe| mof| jvp| tgq| srm| rly| dnx| pfh| cvw| els| hzm| rhd| dcx| msy| ize| vze| wvf| unk| ibj| dzr| ign| vrm| kdl| lgw| otb| pjn| slz| bta| lkq| vrq| gxi| ped| xwu| nkg| hfm| uiy| cco| bdo| kbq| frc| fpa| fwb| qzt| krw| yho| pgf| tvv| ufo|