Mixtures of the rare earth elements are present, but only in small amounts, in most rocks of the Earth. The rare earth elements are more concentrated in rocks of the continents than in those of the ocean basins. The minerals monazite, a phosphate mineral, and bastnäsite, a fluorine-carbonate mineral, form the main ores for the rare earth elements with lower atomic numbers. Xenotime, another phosphate mineral, is mined for its concentration of the rare earth elements with higher atomic numbers.... więcej

Salem Press Encyclopedia of Science, 2023. 2p.