Mineral Information and Data:

CePO4 [CNMNC approved formula]

Named from the Greek for solitary, for its initial apparent rarity, and dominant cerium. First published in 1829. Renamed (IMA, 1997) with Ce modifier.

IMA status : Approved Species 1987 ()
(8th edition) :  
  (38) Anhydrous Phosphates, etc
  (38.04) A+ XO4
  (38.04.03) Monazite Group (Monoclinic: P21/n)
(10th edition) :
  (08) Phosphates, Arsenates, Vanadates
  (08.A) Phosphates, etc. without additional anions, without H2O
  (08.AD) With only large cations
Crystal system: Monoclinic System
Point group (H-M): 2/m — prismatic
Space group: P21/n
Unit cell: a = 6.7902(10) Å, b = 7.0203(6) Å, c = 6.4674(7) Å, β = 103.38°, Z=4
Crystal Habit: Crystals typically tabular on {100}, may be prismatic, equant or wedge-shaped, to 27 cm; granular, massive.
Twinning: Common, {100} as twin and composition plane, as contact twins
Color: Reddish brown, brown, pale yellow, pink, gray; yellowish brown to yellow in transmitted light
Diaphaneity: Translucent to opaque
Luster: Resinous, waxy, vitreous to adamantine
Hardness (Mohs): 5 - 5.5
Measured Density: 4.98 – 5.43 g/cm3
Cleavage: {100}, distinct; {010}, poor; parting on {001} or {111}
Tenacity: Brittle
Fracture: Conchoidal to uneven
Geologic Setting: An accessory mineral in granites, syenites, and their pegmatites; in carbonatites and volcanoclastic rocks; in fissure veins and high-grade metamorphic rocks; commonly detrital in river and beach sands; rarely authigenic in shales and intense weathering zones.
Mineral Association: Zircon, xenotime, titanite, thorite, allanite, columbite, wolframite (pegmatites and Alpine fissures); rhabdophane, cerianite, florencite, churchite (Mt. Weld, Australia).
Other Properties: Radioactive. Paramagnetic (weakly attracted to magnetic fields). Gemstone Unlikely Available.
Comments: Radioactive when metamict; thorium-rich. Dull brown cathodoluminescence.


Monazite-(Ce) in carbonatite
Origin: Mona Lisa Claim, Ravalli Co., Montana, United States
Sample size: 5 x 4.5 x 1 cm
Photo: Tom Loomis


(zoom-in of above)