Athabascaite is a member of the

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

selenide mineral Selenide minerals are those minerals that have the selenide anion as a main component. Selenides are similar to sulfides and often grouped with them. Examples include: * achavalite * athabascaite * clausthalite * ferroselite * penroseite ...

s, and forms with other copper selenides. It was first discovered by S. Kaiman in 1949 while he was researching radioactive materials around

Lake Athabasca Lake Athabasca (; French: ''lac Athabasca''; from Woods Cree: , "herethere are plants one after another") is located in the north-west corner of Saskatchewan and the north-east corner of Alberta between 58° and 60° N in Canada. The lake ...

. Kaiman was conducting research near

Uranium City, Saskatchewan Uranium City is a northern settlement in Saskatchewan, Canada. Located on the northern shores of Lake Athabasca near the border of the Northwest Territories, it is above sea level. The settlement is northwest of Prince Albert, northeast of ...

where mass amounts of

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

mines were present.Harris, D.C., Cabri, L.J., and Kaiman, S. (1970
Athabascaite: A New Copper Selenide Mineral from Martin Lake, Saskatchewan
The Canadian Mineralogist, 10(2), 207-215.

History

Kaiman sent his specimens for testing to J. W. Earley, then a graduate student. With the invention of the microprobe analyzer, D.C. Harris decided to delve further into the virtually unknown mineral with little success.Earley, J.W. (1950
Description and Synthesis of the Selenide Minerals
The

American Mineralogist ''American Mineralogist: An International Journal of Earth and Planetary Materials'' is a peer-reviewed scientific journal covering the general fields of mineralogy, crystallography, geochemistry, and petrology. It is an official journal of the Min ...

35(5&6), 337-364.

Structure

Because of unavailability of sufficiently large single crystals, little is known about the atomic structure of athabascaite. Copper (Cu⁺) serves as the

cations An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

selenium Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...

(Se²⁻) serves as the

anions An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

, and the two are joined by

ionic bonds Ionic bonding is a type of chemical bonding that involves the electrostatic attraction between oppositely charged ions, or between two atoms with sharply different electronegativities, and is the primary interaction occurring in ionic compounds. ...

. The crystal symmetry appears orthorhombic with the lattice parameters a = 8.227 ± 0.01, b = 11.982 ± 0.02, and c = 6.441 ± 0.01 Å. It has a calculated

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...

of 6.59 g/cm³; this density is identical to that of

umangite Umangite is a copper selenide mineral, Cu3 Se2, discovered in 1891. It occurs only in small grains or fine granular aggregates with other copper minerals of the sulfide group. It has a hardness of 3. It is blue-black to red-violet in color with ...

, and therefore the two are thought to have similar structure.

Physical properties

Athabascaite often contains umangite as inclusions and stained

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate g ...

vein material as

stringer Stringer may refer to: Structural elements * Stringer (aircraft), or longeron, a strip of wood or metal to which the skin of an aircraft is fastened * Stringer (slag), an inclusion, possibly leading to a defect, in cast metal * Stringer (stairs), ...

s and

veinlets A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

. When coupled with umangite, the mineral forms

lath A lath or slat is a thin, narrow strip of straight-grained wood used under roof shingles or tiles, on lath and plaster walls and ceilings to hold plaster, and in lattice and trellis work. ''Lath'' has expanded to mean any type of backing mate ...

-shaped slender and elongated grains averaging 20 by 50 micrometers. Athabascaite originally appeared as finer grained than the surrounding material, possessing a core of umangite. Because of the presence of umangite within the core, it is thought that the umangite may recrystallize during the construction of athabascaite. Within the hematite, stained carbonate veins contain massive areas up to 300 micrometers in diameter. The veinlets are composed of a collection of arbitrarily organized crystals which rarely surpass 2 micrometres. These crystallites contain pure athabascaite phase. The color of athabascaite is typically light gray, but can also be white, white-gray, and blue-gray. It has a

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

of approximately 2.50 on the

Mohs scale The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by th ...

. When exposed to polarized light, it displays a range of colors varying from creamy white to dark blue. The display of these distinct colors, along with its

reflectivity The reflectance of the surface of a material is its effectiveness in reflecting radiant energy. It is the fraction of incident electromagnetic power that is reflected at the boundary. Reflectance is a component of the response of the electronic ...

, allows athabascaite to be easily distinguished from other copper selenide minerals. It displays strong anisotropy and distinct

birefringence Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. These optically anisotropic materials are said to be birefringent (or birefractive). The birefring ...

.Johan, Z., Picot, P., and Ruhlmann, F. (1982) Evolution paragenetique de la mineralization uranifere de Chameans (Puy-de-Dôme) France: Chameanite, Geffroyite et Girauditem Trios Seleniures Nouvease de Cu, Fe, Ag, and As. Tshermaks Moneral. Petrog. Mitt., 29, 151-167.

Geologic occurrence

After being discovered in Canada, a few other samples have been found in Petrovice,

Vysočina Region The Vysočina Region (; cs, Kraj Vysočina "Highlands Region", , ) is an administrative unit ( cs, kraj) of the Czech Republic, located partly in the south-eastern part of the historical region of Bohemia and partly in the south-west of the hist ...

, Predborice, and Koksin Hill,

Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...

;

Puy-de-Dôme Puy-de-Dôme (; oc, label=Auvergnat, lo Puèi de Doma or ''lo Puèi Domat'') is a department in the Auvergne-Rhône-Alpes region in the centre of France. In 2019, it had a population of 662,152.Kalmar Kalmar (, , ) is a city in the southeast of Sweden, situated by the Baltic Sea. It had 36,392 inhabitants in 2010 and is the seat of Kalmar Municipality. It is also the capital of Kalmar County, which comprises 12 municipalities with a total of ...

, Sweden; La Rioja Province, Argentina; and most recently

Zaire Zaire (, ), officially the Republic of Zaire (french: République du Zaïre, link=no, ), was a Congolese state from 1971 to 1997 in Central Africa that was previously and is now again known as the Democratic Republic of the Congo. Zaire was, ...

(

Democratic Republic of Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...

); all of which were found in or near uranium mines. In Canada, athabascaite is commonly associated with umangite,

clausthalite Clausthalite is a lead selenide mineral, PbSe. It forms a solid solution series with galena PbS. Occurrence It occurs in low-sulfur hydrothermal deposits with other selenides and in mercury deposits. It is associated with tiemannite, klockmann ...

, eucairite,

berzelianite Berzelianite is a rare copper selenide mineral with the formula Cu2 Se. It occurs as thin dendritic crusts or as fine-grained inclusions. It crystallizes in the isometric system, unlike its dimorph, bellidoite, which crystallizes in the tetrag ...

, sulfatian berzelianite, klockmannite,

eskebornite Eskebornite is a selenide mineral with the formula Cu Fe Se2. It crystallizes in the tetragonal system and it has a brassy colour. Eskebornite is sometimes found as thick tabular crystals, but is more often found intergrown with other selenides ...

tyrrellite Tyrrellite is a selenide mineral that has a chemical formula of . It has been found in the Goldfields District in northern Saskatchewan, as well as in the Petrovice deposit, Czech Republic. It is named after the Canadian geologist Joseph Burr Ty ...

native copper Native copper is an uncombined form of copper that occurs as a natural mineral. Copper is one of the few metallic elements to occur in native form, although it most commonly occurs in oxidized states and mixed with other elements. Native coppe ...

native silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical co ...

uraninite Uraninite, formerly pitchblende, is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2 but because of oxidation typically contains variable proportions of U3O8. Radioactive decay of the uranium causes t ...

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...

pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Luster (mineralogy), lust ...

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

barite Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate ( Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

and

feldspar Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...

. In Argentina and Sweden, it is associated with umangite and berzelianite. In the Czech Republic, it occurs with berzelianite, eucairite,

crookesite Crookesite is a selenide mineral composed of copper and selenium with variable thallium and silver. Characteristics Its chemical formula is reported either as or .http://www.mindat.org/min-1159.html Mindat It is formed by precipitation from hy ...

ferroselite Orthorhombic ferroselite and its isometric polymorph dzharkenite are iron selenides of general formula FeSe2 precipitated under reducing conditions in anoxic environments. They are a source of selenium in the Rocky Mountains where selenium occ ...

bukovite Bukovite is a rare selenide mineral with formula Tl2Cu3FeSe4. It is a brown to black metallic mineral which crystallizes in the tetragonal system. It was first described in 1971 for an occurrence in the Bukov uranium mine, Rožná deposit, Vyso� ...

, krutaite, calcite and

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

. In

, it is associated with

digenite Digenite is a copper sulfide mineral with formula: Cu9S5. Digenite is a black to dark blue opaque mineral that crystallizes with a trigonal - hexagonal scalenohedral structure. In habit it is usually massive, but does often show pseudo-cubic f ...

, berzelianite, yarrowite, spionkopite,

trogtalite Trogtalite is a rare selenide mineral with the formula Co Se2. It crystallizes in the cubic system and is part of the pyrite group, consisting of Co2+ and Se22− ions. It has a rose-violet colour and its crystals are opaque. It often occurs as ...

and

native gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

References

{{reflist, 30em Copper(I,II) minerals Selenide minerals Orthorhombic minerals Uranium City, Saskatchewan