Monazite-(Sm)

Monazite-(Sm) is an exceedingly rare representative of the monazite group, with samarium being the dominant rare earth element in its structure. It is the samarium analogue of monazite-(Ce), monazite-(La), and monazite-(Nd). It is only the second known mineral with samarium being the mineral-forming element, after florencite-(Sm).^[3] The group contains simple rare earth phosphate minerals with the general formula of ATO₄, where A = Ce, La, Nd, or Sm (or, rarely, Bi), and B = P or, rarely, As. The A site may also bear Ca and Th.^[4]

Monazite-(Sm)
General
Category	Phosphate mineral
Formula	SmPO4
IMA symbol	Mnz-Sm[1]
Crystal system	Monoclinic
Crystal class	Prismatic: 2/m
Space group	P21/m
Unit cell	a = 6.725, b = 6.936, c = 6.448 Å; β = 104.02°
Identification
References	[2]