Monazite Value, Price, and Jewelry Information

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Rob Lavinsky, – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons

Monazite may be partially metamict, with N=1.79. Stones can be an attractive yellow or brown color but are usually small.

Monazite Information

Data Value
Name Monazite
Crystallography Monoclinic. Crystals small, tabular, wedge-shaped; faces often rough or uneven; also massive, granular; detrital.
Crystallographic Forms
Refractive Index 1.774-1.849
Colors Brown, reddish brown, yellowish brown, pink, yellow, greenish, grayish white, white.
Luster Vitreous to subadamantine; resinous; waxy.
Hardness 5-5.5
Fracture Conchoidal to uneven
Specific Gravity 4.6-5.4
Birefringence 0.049-0.055. Higher refractive index is accompanied by lower birefringence.
Cleavage Distinct 1 direction, sometimes perfect
Stone Sizes Faceted gems would normally be under 5 carats, either from Swiss crystals or from portions of crystals from other localities. Facetable material is very rare and cut stones are absent from all but a few private collections. Large cabochons could be cut from various large crystals that have been found.
Luminescence None.
Luminescence Present No
Transparency Transparent.
Absorption Spectrum Extremely complex spectra observed, mostly rare earth types.
Formula (Ce,La,Y,Th)PO4.
Pleochroism Faint or none (yellowish shades). Sri Lanka material: reddish orange/golden yellow.
Optics a = 1.774-1.800; β = 1.777-1.801; γ = 1.828-1.849. Biaxial (+), 2V= 11-15°.
Optic Sign Biaxial +

Optics: a=1.774-1.800; β= 1.777-1.801; γ= 1.828-1849.

Biaxial (+), 2V= 11-15°.

Higher refractive index is accompanied by lower birefringence.

Occurrence: An accessory mineral in igneous rocks and gneisses; sometimes in large crystals in granite pegmatites; as a detrital mineral in sands.

Petaca district, New Mexico; Amelia, Virginia.

Norway; Finland.

Colorado: fine crystals.

Wyoming: crystals to several pounds.

Madagascar: in fine crystals.

Switzerland: excellent crystals in alpine vein deposits.

Sri Lanka: orange pebbles.

Callipampa, Bolivia: good crystals.

Deposits of alluvial material in Australia, India, Brazil, Malaysia, Nigeria.

Comments: Monazite may be partially metamict, with N=1.79. Stones can be an attractive yellow or brown color but are usually small.

Name: From the Greek monazein, to be solitary, because of the rarity of the mineral.

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