Glossary

A sorosilicate group of minerals within the broader epidote group that contain a significant amount of rare earth elements occuring mainly in metamorphosed clay rich sediments and felsic igneous rocks. There are three minerals in the allanite group, each recognized as a unique mineral: allanite-(Ce), allanite-(La) and allanite-(Y), depending on the dominant rare earth element present, cerium, lanthanum or yttrium.

A compound that consists of two or more metals, or metals with a nonmetal.

Amblygonite is a fluorophosphate mineral, composed of lithium, sodium, aluminium, phosphate, fluoride and hydroxide. The mineral occurs in pegmatite deposits and is easily mistaken for albite and other feldspars. It contains about 10% lithium, and has been utilized as a source of lithium.

Apatite is a group of phosphate minerals, usually referring to hydroxyapatite, fluorapatite, chlorapatite and bromapatite. The primary use of apatite is in the manufacture of fertilizer. Apatite is occasionally found to contain significant amounts of rare earth elements and can be used as an ore for those metals.

A yellowish to reddish-brown fluorocarbonate mineral that is a source of rare earth elements.

The most abundant of the earth rare elements. Cerium is critical in the manufacture of environmental protection and pollution-control systems, from automobiles to oil refineries. Cerium oxides, and other cerium compounds, go into catalytic converters and larger-scale equipment to reduce the sulfur oxide emissions. Cerium is a diesel fuel additive for micro-filtration of pollutants, and promotes more complete fuel combustion for more energy efficiency.

A high-temperature polymorph of silica, i.e. having the same chemical formula SiO₂ but a distinct crystal structure.

A diffractometer is an instrument for analyzing the structure of a usually crystalline material from the diffraction pattern produced when an X-ray beam interacts with it.

Dysprosium is a rare earth element that has a metallic, bright silver luster. Its physical characteristics can be greatly affected even by small amounts of impurities. Dysprosium is never found in nature as a free element, though it is found in various minerals, such as xenotime. Dysprosium is used in electronic components to make them smaller and faster.

A rare earth element that offers exceptional properties of photon emission. When it absorbs electrons or UV radiation, the europium atom changes energy levels to create a visible, luminescent emission. This emission creates the perfect red phosphors used in color televisions and computer screens around the world. Europium is also used in fluorescent lighting, which cuts energy use by 75% compared to incandescent lighting. In the medical field, europium is used to tag complex biochemical agents which helps to trace these materials during tissue research.

A group of rock-forming tectosilicate minerals which make up as much as 60% of the earth's crust. Feldspar is a common raw material used in glassmaking, ceramics, and to some extent as a filler and extender in paint, plastics, and rubber.

A rare earth element with unique magnetic behavior. Thus this element is at the heart of magneto-optic recording technology, and other technology used in handling computer data.

A rare soft, greasy, white clay mineral. Hectorite is mostly used in making cosmetics, but has uses in chemical and other industrial applications, and is a mineral source for refined lithium metal.

Heavy rare earth elements (HREE) are the fraction of REE from gadolinium to lutetium accompanied by yttrium and scandium.

A reversible chemical reaction between an insoluble solid and a solution during which ions may be interchanged.

A very rare white, earthy monoclinic silicate mineral that is relatively hard but very small grained. Jadarite contains boron and lithium, two valuable elements that are used in many applications e.g. in batteries or pharmaceutical industry.

Kaolin is a soft, earthy, usually white mineral, produced by the chemical weathering of aluminium silicate minerals like feldspar. Kaolin is used in ceramics, medicine, coated paper, as a food additive in toothpaste, as a light diffusing material in white incandescent light bulbs, and in cosmetics. It is generally the main component in porcelain.

A rare earth element that is extracted from the minerals bastnaesite and monazite via “solvent extraction”. Lanthanum is a strategically important rare earth element due to its activity in catalysts that are critical in petroleum refining. By one estimate, lanthanum “cracking-agents” increase refinery yield by as much as 10%, while reducing overall refinery power consumption.

The ore, referred to as REE bearing ionic adsorption clay, mostly comes from two districs in the Jiangxi Province, Lognan and Xunwu, the former yielding exceptional HREE- and yttrium-rich material and the other, LREE-rich material.

A lilac-gray or rose-colored phyllosilicate mineral of the mica group that is a secondary source of lithium. It is associated with other lithium bearing minerals like spodumene in pegmatite bodies. It is also one of the major sources of the rare alkali metals rubidium and caesium. Lepidolite occurs in granite pegmatites, in some high-temperature quartz veins, greisens and granites.

A soft, silver-white metal that belongs to the alkali metal group of chemical elements. Because of its high reactivity, lithium never occurs in its elemental form in nature, and instead, only appears in compounds. Lithium occurs in a number of pegmatitic minerals, but is also commonly obtained from brines and clays. On a commercial scale, lithium is isolated electrolytically from a mixture of lithium chloride and potassium chloride. Main application fields of lithium are ceramics and glass, lithium-ion batteries and lubricating greases.

A chemical compound of lithium, carbon, and oxygen. This colorless salt is widely used in the processing of metal oxides and has received attention for its use in psychiatry.

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.

Light rare earth elements (LREE) are the light fraction of the REE from lanthanum to europium.

The science of extracting metals from their ores, purifying and alloying metals and creating useful objects from metals. The study of metals in bulk and at the atomic level.

A reddish-brown phosphate mineral that contains rare earth elements.

A rare earth element that is a critical component of strong permanent magnets. Cell phones, portable CD players, computers and most modern sound systems would not exist in their current form without the use of neodymium magnets. Neodymium-Iron-Boron (NdFeB) permanent magnets are essential for miniaturizing a variety of technologies. These magnets maximize the power/cost ratio, and are used in a large variety of motors and mechanical systems.

A rock that contains minerals bearing elements of economic value in economic concentrations that can be extracted by processing.

An oxide is any compound of oxygen with another element or radical.

A very coarse-grained intrusive igneous rock composed of interlocking grains usually larger than 2.5 cm size. Most pegmatites are composed of quartz, feldspar and mica. Pegmatites often contain rare earth minerals and gemstones, such as aquamarine, tourmaline, topaz, fluorite, apatite and corundum. They are also the primary source of lithium either as spodumene, lithiophyllite or usually from lepidolite (Li-mica).

Petalite, also known as castorite, is a lithium aluminium tectosilicate mineral, crystallizing in the monoclinic system. It occurs in lithium bearing pegmatites with spodumene, lepidolite, and tourmaline. Petalite is an important ore of lithium, and is converted to spodumene and silica by roasting.

The world largest REE source (Bayan Obo, China) is a giant polymetallic Iron-Niobium-REE deposit now regarded as a hydrothermal carbonate replacement, formed within sedimentary rocks (shale and marble) during a duration of 150 Mio years.

This rare earth element comprises at most 4% of the lanthanide content of bastnaesite, but is used as a common coloring pigment. Along with neodymium, praseodymium is used to filter certain wavelengths of light. So praseodymium finds specific uses in photographic filters, airport signal lenses, welder’s glasses, as well as broad uses in ceramic tile and glass (usually yellow). When used in an alloy, praseodymium is a component of permanent magnet systems designed for small motors. Praseodymium also has applications in internal combustion engines, as a catalyst for pollution control.

A solid solution between the niobium end member (pyrochlore) and the tantalum end member (microlite). Pyrochlore occurs in pegmatites associated with nepheline syenites and other alkalic rocks. It is also found in granite pegmatites and greisens. It is characteristically found in carbonatites.

Well known minerals that contain REE include bastnaesite, monazite, xenotime, loparite, eudialyte, steenstrupin, euxenite, florencite, allanit, ancylite, parisite, cheralite, birtholite, apatite, ceranite and many more.

Rare earth elements are a continuous series of 15 metallic elements known as the lanthanides plus scandium and yttrium.

The Rietveld method is a technique used in powder diffraction analysis to refine structural models and quantify crystalline phases by fitting a theoretical line profile to the observed profile using a least squares refinement approach.

Scandium is number 21 on the periodic table of elements. It is considered a rare earth element but is not part of the lanthanide series. It is used to produce high performance materials in both the aerospace and sporting goods industries. It is also used in lighting, lasers and consumer electronics.

Silica - also know as silicon dioxide - is an oxide of silicon with chemical formula SiO₂. It has been known for its hardness since antiquity. Silica is most commonly found in nature as sand or quartz, as well as in the cell walls of diatoms. Silica is used primarily in the production of glass for windows, drinking glasses, beverage bottles, and many other uses. The majority of optical fibers for telecommunications are also made from silica. It is a primary raw material for many whiteware ceramics such as earthenware, stoneware and porcelain.

A pyroxene mineral consisting of lithium aluminium inosilicate. It occurs as colorless to yellowish, purplish, or lilac kunzite, yellowish-green or emerald-green hiddenite, prismatic crystals, often of great size. Spodumene is an important source of lithium for use in ceramics, mobile phone and automotive batteries, medicine and as a fluxing agent. Lithium is extracted from spodumene by fusing in acid.

Technical ceramics are also known as engineering, advanced, special, and in Japan, fine ceramics. Such items include tiles used in the Space Shuttle program, gas burner nozzles, ballistic protection, nuclear fuel uranium oxide pellets, biomedical implants, coatings of jet engine turbine blades and missile nose cones.

A rare earth element used in energy efficient fluorescent lamps. There are various terbium metal alloys that provide metallic films for magneto optic data recording.

A soft silvery-white tetravalent radioactive metallic element, isotope 232, that is used as a power source in nuclear reactors. Thorium is present in the phosphate mineral monazite and in silicate and oxide minerals such as e.g. allanite and thorianite.

X-ray diffraction is a non-destructive method used to probe crystalline structures at the atomic level. It can be used to determine arrangement of the atoms within a crystal and to identify crystalline phases.

A rare earth phosphate mineral, whose major component is yttrium orthophosphate. The rare earths dysprosium, erbium, terbium, and ytterbium, and metal elements like thorium and uranium are the expressive secondary components of xenotime. Occurring as a minor accessory mineral, xenotime is found in pegmatites and other igneous rocks, as well as gneisses rich in mica and quartz.

A rare earth element. Almost every vehicle on the road contains yttrium based materials that improve the fuel efficiency of the engine. Another important use of yttrium is in microwave communication devices. Yttrium- Iron- Garnets (YIG) are used as resonators in frequency meters, magnetic field measurement devices, tunable transistors and Gunn oscillators. Yttrium goes into laser crystals specific to spectral characteristics for high-performance communication systems.

A mineral belonging to the group of nesosilicates. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green. Zircon is ubiquitous in the earth's crust. It occurs in igneous rocks, in metamorphic rocks and in sedimentary rocks. Zircon is mainly consumed as a opacifier in the decorative ceramics industry.