Bastnäsite
A key rare-earth fluorocarbonate mineral and major cerium source.
Bastnäsite is a family of three fluorocarbonate minerals, officially divided into bastnäsite-(Ce), bastnäsite-(La), and bastnäsite-(Y) based on the predominant rare-earth element. Most natural bastnäsite is bastnäsite-(Ce), with cerium dominating the composition. Along with the phosphate mineral monazite, bastnäsite is one of the two largest sources of cerium and other rare-earth elements. The mineral was first described in 1838 by Swedish chemist Wilhelm Hisinger, who named it after the Bastnäs mine near Riddarhyttan, Västmanland, Sweden. Ore from this mine had previously led to the discovery of the elements cerium and lanthanum by Swedish scientists including Hisinger, Jöns Jakob Berzelius, and Carl Gustav Mosander. Bastnäsite occurs in alkali granite, syenite, and associated pegmatites, as well as in carbonatites and related metasomatic rocks. Notable occurrences include the Mountain Pass rare earth mine in California, where bastnäsite is the primary ore mineral, and the Zagi Mountains in Pakistan, which yield high-quality specimens. The mineral is closely related to parisite, another rare-earth fluorocarbonate; the two can alter back and forth with the addition or loss of calcium carbonate in natural environments. Bastnäsite also forms a substitution series with hydroxylbastnäsite, where fluoride ions are replaced by hydroxyl ions.
- type
- Mineral family
- composition
- (Ce, La)CO3F, (La, Ce)CO3F, (Y, Ce)CO3F
- named_for
- Bastnäs mine, Sweden
- major_sources
- Mountain Pass (USA), Bayan Obo (China), Sichuan Province (China)
- associated_rocks
- Alkali granite, syenite, pegmatites, carbonatites, fenites
Lore & Background
It is named for the Bastnäs mine near Riddarhyttan, Västmanland, Sweden. Bastnäsite occurs in alkali granite and syenite and in associated pegmatites, as well as in carbonatites and associated fenites. Notable occurrences include the Zagi Mountains in Pakistan, the Fen Complex in Norway, Bayan Obo in Inner Mongolia, Kangankunde in Malawi, Kizilcaoren in Turkey, and the Mountain Pass rare earth mine in California. It also appears in karst bauxite deposits in Hungary, Greece, and the Balkans, and in unusual granites in Norway, Russia, Canada, and the Northwest Territories. Bastnäsite forms a series with hydroxylbastnäsite-(Ce) and hydroxylbastnäsite-(Nd), involving substitution of fluoride ions with hydroxyl ions. It is closely related to the mineral series parisite, which contains calcium and neodymium; the two can alter back and forth with the addition or loss of CaCO3 in natural environments.
Reader's Guide
Bastnäsite is significant as one of the two largest sources of cerium and other rare-earth elements, critical for modern industry. Mountain Pass bastnäsite was the world's major source of lanthanides from the 1960s to the 1980s, supplying europium oxide needed for color television red phosphors. Since then, Chinese deposits, particularly Bayan Obo in Inner Mongolia, have become the dominant global source. Bastnäsite ore is processed via flotation, acid treatment, calcination, and solvent extraction to produce rare-earth metals. The mineral's composition varies: Mountain Pass ore contained about 49% cerium, 33% lanthanum, 12% neodymium, and 5% praseodymium, with higher europium content than monazite. Bayan Obo bastnäsite occurs with monazite and magnetite and has a composition closer to monazite but with 0.2% europium. Bastnäsite remains essential for rare-earth supply chains.
Did You Know?
- Most bastnäsite is bastnäsite-(Ce), and cerium is by far the most common rare earth in this mineral class.
- Bastnäsite and monazite are the two largest sources of cerium and other rare-earth elements.
Frequently Asked Questions
What is Bastnäsite?
Bastnäsite is a family of three fluorocarbonate minerals—bastnäsite-(Ce), bastnäsite-(La), and bastnäsite-(Y)—that together form one of the two primary sources of rare-earth elements on Earth.
What is Bastnäsite's chemical composition?
Each member pairs a rare-earth cation (cerium, lanthanum, or yttrium) with a carbonate group and a single fluorine atom, giving formulas such as (Ce, La)CO₃F or (Y, Ce)CO₃F.
Where can I find Bastnäsite in nature?
The largest deposits are at Mountain Pass in California, Bayan Obo in Inner Mongolia, and Sichuan Province in China, typically hosted in alkali granites, syenites, pegmatites, carbonatites, or fenites.
Why is Bastnäsite important to industry?
It is the dominant mineral source of cerium—the most abundant rare earth in the family—and supplies critical elements used in magnets, polishing compounds, and catalysts, with the phosphate mineral monazite being the only other major supplier.
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