Formula: Ce(PO₄) Always contains major to minor amounts of other REE (Nd, La, Sm, …) replacing Ce. Also often contains trace amounts of U and Th (coupled with Ca).

Species:

Colour: Commonly reddish brown to brown; shades of green to brown, yellow brown, rarely nearly white; yellow, colourless in transmitted light.

Lustre: Sub-Adamantine, Vitreous, Sub-Vitreous, Resinous, Waxy, Greasy

Hardness: 5 – 5½

Specific Gravity: 5 – 5.5

Crystal System: Monoclinic

Member of: Monazite Group > Monazite Group

Name: Named in 1829 by Johann Friedrich August Breithaupt from the Greek μουάζω “to be solitary” in allusion to the rarity of its presence in the first known localities. The suffix “Ce” conforms to the Levinson Rule for rare earth minerals, for the cerium dominant member of the monazite series.

Type Locality: Ilmen Nature Reserve, Chelyabinsk Oblast – Russia

The overwhelmingly most common member of the monazite group. Monazite-(Ce) is a widely distributed mineral, as an accessory in granitic igneous rocks and gneissic metamorphic rocks, and in detrital sands derived from them.