Monazite is a mineral belonging to the group of phosphates that contains rare earth elements, among which cerium, thorium and lanthanum stand out. Technically, monazite represents a group of four different phosphates, but since there are no major differences between them, they are still called “monazite.”
The mineral was named in the year 1829 by Johann Friedrich August Breithaupt, a German mineralogist. The term comes from the Greek “monazein”, which means “to be alone”, and refers to the appearance of the mineral in the form of isolated crystals.
Below, you will find all the characteristics of this stone, including its physical-chemical properties, its origin and its uses today.
Properties and characteristics of the monazite gem
The monazite stone describes a group of phosphate minerals that are similar to each other and whose visual differences They are practically impossible to distinguish.. Therefore, it is not common for there to be a distinction between the different types of monazite.
| monazite | Physical and chemical properties |
|---|---|
| chemical classification | Phosphate |
| Color | Yellowish to reddish brown, greenish |
| Stripe | white |
| Gloss | resinous, waxy, vitreous |
| diaphanousness | Translucent |
| cleavage | good to poor |
| Mohs hardness | 5 to 5.5 |
| specific gravity | 4.6 to 5.4 (varies greatly depending on rare earth type and concentration) |
| diagnostic properties | specific gravity |
| Chemical composition | (Ce, La, Nd, Th) PO4 |
| crystal system | monoclinic |
| Applications | A major source of thorium, cerium, and other rare elements. Often mined as a byproduct of heavy mineral deposits. |
The element that predominates most frequently in this mineral is cerium, so its generic chemical formula is (Ce, La, Nd, Th)PO4. However, lanthanum and neodymium can also dominate. Monazite can also contain uranium, thorium, and yttrium.
Due to its composition, there are four types of monazite:
- Monazite-(Ce), whose formula is (Ce, La, Pr, Nd, Th, Y) PO4
- Monazite-(The), whose formula is (La, Ce, Nd, Pr) PO4
- Monazite-(Nd), whose formula is (Nd, La, Ce, Pr) PO4
- Monazite-(Sm), whose formula is (Sm, Gd, Ce, Th) PO4
All these minerals have the same monocyclic crystal system, while their colors can vary between brown, yellowish brown, reddish brown, orange, yellow and pink.
The crystals are prismatic and tabular., commonly with a coarse shape and several crystal faces. The hardness of monazite stone is 5 to 5.5 on the Mohs scale, while its luster is resinous to vitreous. Also, monazite stone is radioactive, so its decomposition is slow.
Meaning and metaphysical properties of the mineral monazite
Because monazite is a radioactive compound of rare earths, its effects on human health are toxic and exposure should be limited. For this reason, its use by believers of spirituality or metaphysics is not known, as it usually occurs in other minerals.
Origin, formation and deposits of monazite
The monazite stone occurs in the form of small heavy resinous crystals in igneous and metamorphic rocks such as gneiss, granite, pegmatite and schist. These grains are weather resistant and are concentrated in sediments and soils that descend from the host rock.
If their concentration is high enough, the grains are mined for their high value of thorium and rare earths.
Although monazite is found throughout the planet, crystals of large size and shape are not common. Sharp and large prismatic crystals of monazite-(Ce), the most frequent mineral in the group, come from different locations in Iveland, a municipality in the province of Agder, in the Norwegian region of Sørlandet.
In addition, large, brown-colored crystals have been found in Madagascar, Bolivia, and Brazil.
In the US, you can find monazite of brown color and round shape in Colorado, while another group of large monazite crystals also comes from Texas, Connecticut, Virginia, and Portland.
Monazite-(La) generally comes from Russia, while Monazite-(Nd) comes from the Ossola Valley area of Italy.
Monazite Mineral Uses
The monazite stone is used as natural source of cerium, lanthanum and thorium. Due to the presence of this last element, this mineral is radioactive.
Cerium oxide of cerium, obtained from monazite, represents an essential compound for polishing Therefore, it is often used to polish gemstones and glass products (lenses, cameras, and other components of optical instruments).
The lanthanum that comes from monazite is used as catalyst in the complex oil refining process. For its part, neodymium, a component of monazite, can be incorporated into the crystal to give it a violet appearance.