Monazite is one of the rare earth carbonate minerals. In fact, what we know as Monazite is technically three different minerals, but because of a lack of any significant differences between them they are referred to as one mineral. Monazite-(La) ((La, Ce, Nd)PO4) is greatly enriched in lanthanum, Mozanite-(Ce) ((Ce, La, Nd, Th, Y)PO4) in cerium and Monazite-(Nd) ((Nd, La, Ce)PO4) in neodymium. Mozanite-(Ce) is by far the most common and any sample labelled Monazite will generally be this variant.
Monazite is a primary ore of several rare earth metals most notably thorium, cerium and lanthanum. All these metals have various industrial uses and are considered quite valuable. Thorium is a highly radioactive metal and could be used as a replacement for uranium in nuclear power generation. Monazite is thus an extremely important ore mineral.
The name monazite comes from a Greek word, "monazeis", which means "to be alone", an allusion to the mineral's isolated crystals and their rarity when first discovered.
Generally found in beach and river sand deposits spread across the globe and including India, Australia, Brazil, Sri Lanka, Malaysia, Nigeria, Florida and North Carolina, USA.
- Empirical Formula: Ce0.5La0.25Nd0.2Th0.05(PO4)
- Color is yellow to brown or orange-brown.
- Luster is vitreous, resinous or adamantine.
- Transparency: Specimens are translucent to opaque, but small crystals can be transparent.
- Crystal System is monoclinic
- Cleavage is perfect in one direction, poor in several other directions. The result is often shards or acutely angled splinters.
- Fracture is uneven but gradationally converts to conchoidal with metamictation.
- Hardness is variable from 5 - 5.5
- Specific Gravity is approximately 4.6 - 5.7 (heavy for translucent minerals)