Gadolinite, sometimes known as ytterbite, is a silicate mineral consisting principally of the silicates of cerium, lanthanum, neodymium, yttrium, beryllium, and iron with the formula (Ce,La,Nd,Y)2FeBe2Si2O10. It is called gadolinite-(Ce) or gadolinite-(Y), depending on the prominent composing element. It may contain 35.5% yttria sub-group rare earths, 2.2% ceria earths, as much as to 11.6% BeO, and traces of thorium. It is found in Sweden, Norway, and the US.
Zirkelite is an oxide mineral with the chemical formula (Ca,Th,Ce)Zr(Ti,Nb)2O7. It occurs as well-formed fine sized isometric crystals. It is a black, brown or yellow mineral with a hardness of 5.5 and a specific gravity of 4.7.
Samarskite is a radioactive rare earth mineral series which includes samarskite-(Y), with the chemical formula (YFe3+Fe2+U,Th,Ca)2(Nb,Ta)2O8 and samarskite-(Yb), with the chemical formula (YbFe3+)2(Nb,Ta)2O8. The formula for samarskite-(Y) is also given as (Y,Fe3+,U)(Nb,Ta)O4.
Allanite (also called orthite) is a sorosilicate group of minerals within the broader epidote group that contain a significant amount of rare-earth elements. The mineral occurs mainly in metamorphosed clay-rich sediments and felsic igneous rocks. It has the general formula A2M3Si3O12[OH], where the A sites can contain large cations such as Ca2+, Sr2+, and rare-earth elements, and the M sites admit Al3+, Fe3+, Mn3+, Fe2+, or Mg2+ among others. However, a large amount of additional elements, including Th, U, Be, Zr, P, Ba, Cr and others may be present in the mineral. The International Mineralogical Association lists four minerals in the allanite group, each recognized as a unique mineral: allanite-(Ce), allanite-(La), allanite-(Nd), and allanite-(Y), depending on the dominant rare earth present: cerium, lanthanum, neodymium or yttrium.
Aeschynite-(Ce) is a rare earth mineral of cerium, calcium, iron, thorium, titanium, niobium, oxygen, and hydrogen with chemical formula (Ce,Ca,Fe,Th)(Ti,Nb)2(O,OH)6. Its name comes from the Greek word αισχύνη ("aeschyne") for "shame" because early chemists had difficulty with separations of titanium from zirconium.
Aeschynite-(Nd) is a rare earth mineral of neodymium, cerium, calcium, thorium, titanium, niobium, oxygen, and hydrogen with the chemical formula (Nd,Ce,Ca,Th)(Ti,Nb)2(O,OH)6. Its name comes from the Greek word for "shame". Its Mohs scale rating is 5 to 6. It is a member of the hydroxide minerals.
Aeschynite-(Y) is a rare earth mineral of yttrium, calcium, iron, thorium, titanium, niobium, oxygen, and hydrogen with the chemical formula (Y,Ca,Fe,Th)(Ti,Nb)2(O,OH)6. Its name comes from the Greek word for "shame". Its Mohs scale rating is 5 to 6.
Polycrase or polycrase-(Y) is a black or brown metallic complex uranium yttrium oxide mineral with the chemical formula (Y,Ca,Ce,U,Th)(Ti,Nb,Ta)2O6. It is amorphous. It has a Mohs hardness of 5 to 6 and a specific gravity of 5. It is radioactive due to its uranium content. It occurs in granitic pegmatites.
Warwickite is an iron magnesium titanium borate mineral with the chemical formula (MgFe)3Ti(O, BO3)2orMg(Ti,Fe3+, Al)(BO3)O. It occurs as brown to black prismatic orthorhombic crystals which are vitreous and transparent. It has a Mohs hardness of 3 to 4 and a specific gravity of 3.36.
Cerite is a complex silicate mineral group containing cerium, formula (Ce,La,Ca)
9(Mg,Fe3+
)(SiO
4)
6(SiO
3OH)(OH)
3. The cerium and lanthanum content varies with the Ce rich species and the La rich species. Analysis of a sample from the Mountain Pass carbonatite gave 35.05% Ce
2O
3 and 30.04% La
2O
3.
Titanowodginite is a mineral with the chemical formula MnTiTa2O8. Titanowodginite has a Mohs hardness of 5.5 and a vitreous luster. It is an iridescent dark brown to black crystal that commonly forms in a matrix of smoky quartz or white beryl in a complex zoned pegmatite.
Davidite is a rare earth oxide mineral with chemical end members La and Ce. It exists in two forms:
Loparite-(Ce) is a granular, brittle oxide mineral of the perovskite class. It is black to dark grey and may appear grey to white in reflected light on polished thin section with reddish brown internal reflections. It has the chemical formula of (Ce,Na,Ca)(Ti,Nb)O3. Nioboloparite is a variation of loparite-(Ce) containing niobium.
Yuksporite is a rare inosilicate mineral with double width, unbranched chains, and the complicated chemical formula K4(Ca,Na)14Sr2Mn(Ti,Nb)4(O,OH)4(Si6O17)2(Si2O7)3(H2O,OH)3. It contains the relatively rare elements strontium, titanium and niobium, as well as the commoner metallic elements potassium, calcium, sodium and manganese. As with all silicates, it contains groups of linked silicon and oxygen atoms, as well as some associated water molecules.
Betafite is a mineral group in the pyrochlore supergroup, with the chemical formula (Ca,U)2(Ti,Nb,Ta)2O6(OH). Betafite typically occurs as a primary mineral in granite pegmatites, rarely in carbonatites. Originally defined by the B-site atom Ti, the development of new nomenclature for mineral names led to modernization of the system for nomenclature of pyrochlore and betafite in order to further rationalize the naming process of this grouping of minerals. Only two of the mineral species that were formerly recognized as betafite are presently retained. They are oxyuranobetafite and oxycalciobetafite. The term betafite is now a synonym or varietal group name under the pyrochlore super group.
Ancylite is a group of hydrous strontium carbonate minerals containing cerium, lanthanum and minor amounts of other rare-earth elements. The chemical formula is Sr(Ce,La)(CO3)2(OH)·H2O with ancylite-Ce enriched in cerium and ancylite-La in lanthanum.
Cleusonite is a member of the crichtonite group of minerals with the chemical formula (Pb,Sr)(U4+
,U6+
)(Fe2+
,Zn)
2(Ti,Fe2+
,Fe3+
)
18(O,OH)
38. This group of minerals contains approximately thirteen complex metal titanates. The structures of minerals of this group is complicated by frequent fine-scale twinning and metamictization due to radioactive elements. The crichtonite group consists of members of related mineral species of the type A{BC2D6E12}O38 which are characterized by their predominant cations (as seen in crichtonite (Sr), senaite (Pb), davidite (REE + U), landauite (Na), loveringite (Ca), lindsleyite (Ba), and mathiasite (K).
Ixiolite is an accessory oxide mineral found in granitic pegmatites. It is an oxide with the general chemical formula (Ta,Nb,Sn,Mn,Fe)4O8 or (Ta,Mn,Nb)O2.
Vigezzite is a variant of the mineral aeschynite containing calcium, cerium, niobium, tantalum, and titanium. It was first discovered near Orcesco, Valle Vigezzo, Provo Novara, Northern Italy, in cavities of an albitic rock. The crystals of Vigezzite are flat prismatic crystals up to 2-3 mm length of an orange-yellow color.The name Vigezzite was chosen to draw attention to the locality that has produced the first occurrence of a Ca-Nb-Ta-mineral with Nb dominance over Ta, crystallizing with the aeschynite structure. The ideal chemical formula for vigezzite is (Ca,Ce),(Nb,Ta,Ti)2O6
Uranopolycrase is an oxide mineral first discovered in the Fonte del Prete vein of a pegmatite vein in San Piero in Campo, Elba Island, Tuscany, Italy. Uranopolycrase is a member of the Euxenite Group and is the uranium bearing analog of polycrase-(Y). The type specimen is almost entirely metamict. The ideal formula for uranopolycrase is (U,Y)(Ti,Nb)2O6. The mineral has been approved by the Commission on New Minerals and Mineral Names of the International Mineralogical Association to be named uranopolycrase for its similarity to polycrase-(Y) and was approved 5 December, 1991.
Radioactive 