Monazite is a phosphorus-cerium-lanthanum mineral ore that contains (Ce,La,Nd,Th)(PO4,SiO4). It crystallizes in the monoclinic system, and the crystals are blocky or prismatic. It can be brown, reddish brown, yellowish brown, pink, yellow, light green or white with white streaks. It has transparent to translucent diaphaneity, a resinous, waxy or vitreous lustre, a specific gravity of 5.1, and a Mohs hardness of 5–5.5. It mainly forms in pegmatite and coexists with zircon, apatite and niobium ore. However, monazite ore is mainly found in littoral and alluvial placer deposits. It is the main mineral ore for extracting cerium, lanthanum and thorium.