Crossword clues for monazite
The Collaborative International Dictionary
Monazite \Mon"a*zite\ (m[o^]n"[.a]*z[imac]t), n. [From Gr. mona`zein to be solitary, in allusion to its isolated crystals.] (Min.) A mineral occurring usually in small isolated crystals, -- a phosphate of the cerium metals.
Wiktionary
n. (context mineralogy English) any of a range of reddish-brown minerals that are mixed phosphates of the lighter rare earth elements lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium and yttrium
WordNet
n. a reddish-brown mineral containing rare earth metals; an important source of thorium and cerium
Wikipedia
Monazite is a reddish-brown phosphate mineral containing rare earth metals. It occurs usually in small isolated crystals. It has a hardness of 5.0 to 5.5 on the Mohs scale of mineral hardness and is relatively dense, about 4.6 to 5.7 g/cm. There are at least four different kinds of monazite, depending on relative elemental composition of the mineral:
- Monazite-( Ce), (Ce, La, Nd, Th)PO (the most common member)
- Monazite-( La), (La, Ce, Nd)PO
- Monazite-( Nd), (Nd, La, Ce)PO
- Monazite-( Sm), (Sm, Gd, Ce, Th)PO
The elements in parentheses are listed in the order of their relative proportion within the mineral: lanthanum is the most common rare earth element in monazite-(La), and so forth. Silica (SiO) is present in trace amounts, as well as small amounts of uranium and thorium. Due to the alpha decay of thorium and uranium, monazite contains a significant amount of helium, which can be extracted by heating.
Monazite is an important ore for thorium, lanthanum, and cerium. It is often found in placer deposits. India, Madagascar, and South Africa have large deposits of monazite sands. The deposits in India are particularly rich in monazite.
Monazite is radioactive due to the presence of thorium and, less commonly, uranium. Because of its radioactive nature, monazite is a useful for radiometric dating of geological events, such as crystallization, heating, or deformation of the rocks containing monazite.
The name monazite comes from the Greek μονάζειν (to be solitary), via German Monazit, in allusion to its isolated crystals.
Usage examples of "monazite".
So we mine monazite, which contains enough thulium for ion-exchange techniques to make it practical to extract.
It also occurs as phosphate in monazite, and as fluoride in fluocerite.