Monazite-(Ce) is the most common representative of the monazite group. 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 AXO₄, where A = Ce, La, Nd, or Sm (or, rarely, Bi), and X = P or, rarely, As. The A site may also bear Ca and Th.^[4]

Monazite-(Ce)
Monazite-(Ce), Quartz. Locality: Siglo Veinte Mine (Siglo XX Mine; Llallagua Mine; Catavi), Llallagua, Rafael Bustillo Province, Potosí Department, Bolivia (Locality at mindat.org). Size: 3.5 × 2.6 × 1.3 cm.
General
Category	Phosphate mineral
Formula (repeating unit)	CePO4
IMA symbol	Mnz-Ce[1]
Crystal system	Monoclinic
Crystal class	Prismatic: 2/m
Space group	P21/b
Unit cell	a = 6.7902, b = 7.0203, c = 6.4674 [Å]; β = 103.6°
Identification
References	[2]