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Monazite is a primarily reddish-brown phosphate mineral that contains rare-earth elements. Due to variability in composition, monazite is considered a group of minerals. [3] The most common species of the group is monazite-(Ce), that is, the cerium-dominant member of the group. [4] It occurs usually in small isolated crystals.
It is the cerium-dominant analogue of monazite-(La), monazite-(Nd), and monazite-(Sm). It is also the phosphorus analogue of gasparite-(Ce). [3] The group contains simple rare earth phosphate minerals with the general formula of AXO 4, where A = Ce, La, Nd, or Sm (or, rarely, Bi
Monazite is a rare-earth-element phosphate mineral, with the chemical formula e.g. (Ce, La, Nd, Th, Y)PO 4.It appears in a small amount as an accessory mineral in many igneous, metamorphic and sedimentary rocks. [2]
Monazite has characteristics of high closure temperature (>1000 °C), variable composition, and robustness under a large temperature range, which help in the record of geological history in metamorphic rocks. [32] An electron microprobe is usually used for the measurement of monazite composition. [33]
The composition of the lanthanides was about 49% cerium, 33% lanthanum, 12% neodymium, and 5% praseodymium, with some samarium and gadolinium, or distinctly more lanthanum and less neodymium and heavies as compared to commercial monazite. The europium content was at least double that of a typical monazite.
The source rocks which provide the heavy mineral sands determine the composition of the economic minerals. The source of zircon, monazite, rutile, sometimes tungsten, and some ilmenite is usually granite. The source of ilmenite, garnet, sapphire and diamond is ultramafic and mafic rocks, such as kimberlite or basalt.
Monazite-(La) is a relatively rare representative of the monazite group, with lanthanum being the dominant rare earth element in its structure. As such, it is the lanthanum analogue of monazite-(Ce) , monazite-(Nd) , and monazite-(Sm) .
This variety of monazite is typically colored bright rose-red. It is the neodymium analogue of monazite-(Ce) , monazite-(La) , and monazite-(Sm) . [ 4 ] The group contains simple rare earth phosphate minerals with the general formula of A T O 4 , where A = Ce, La, Nd, or Sm (or, rarely, Bi), and B = P or, rarely, As.