Monazite-(Ce)
Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
Mineral NameMonazite-(Ce)
Chemical Formula(Ce,La,Nd,Th)PO₄
Mohs Hardness5
Crystal Systemmonoclinic
Lusterresinous
Streak Colorwhite
Cleavagedistinct on {100}, poor on {010} and {110}
Fractureconchoidal
Specific Gravity4.6
Colorsyellow, yellowish-brown, reddish-brown, brown, green, white, colorless
Transparencytranslucent
Type LocalitySiglo Veinte Mine (Siglo XX Mine; Llallagua Mine; Catavi), Llallagua, Rafael Bustillo Province, Potosí Department, Bolivia
Mineral Groupphosphates
Usesrare-earth element ore, thorium ore, collector
Associated Mineralsquartz, feldspar, zircon, ilmenite, magnetite, rutile, apatite, xenotime
Rarityuncommon
Description
This specimen displays a cluster of twinned, orange-brown Monazite-(Ce) crystals exhibiting a resinous luster, perched on a matrix of smaller, clear to smoky quartz crystals.
Geological Context
Monazite typically forms in granitic pegmatites, high-temperature metamorphic rocks like gneisses and schists, and is also found as resistant detrital grains in placer deposits.
