Coconinoite is a uranium ore that was discovered in

Coconino County, Arizona Coconino County is a County (United States), county in the north-central part of the U.S. state of Arizona. Its population was 145,101 at the 2020 United States census, 2020 census. The county seat is Flagstaff, Arizona, Flagstaff. The count ...

. It is a

phosphate mineral Phosphate minerals contain the tetrahedrally coordinated phosphate (PO43−) anion along sometimes with arsenate (AsO43−) and vanadate (VO43−) substitutions, and chloride (Cl−), fluoride (F−), and hydroxide (OH−) anions that also fit i ...

; or

uranyl The uranyl ion is an oxycation of uranium in the oxidation state +6, with the chemical formula . It has a linear structure with short U–O bonds, indicative of the presence of multiple bonds between uranium and oxygen. Four or more ligands may ...

phosphate mineral along with other subclass uranium U⁶⁺ minerals like blatonite, boltwoodite, metazeunerite and rutherfordine.

Composition

The

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

is Fe₂Al₂(UO₂)₂(PO₄)₄(SO₄)(OH)₂·20H₂O.Young.E, Weeks, A.D, and Merowitz, R. (1996) Coconinoite a new mineral from Utah and Arizona. The American Mineralogist 51, 651-663 The chemical formula was derived from the

spectrographic In chemical analysis, chromatography is a laboratory technique for the separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it through a system (a ...

analysis.

Physical properties

The mineral has a white streak and a pale creamy yellow color. The mineral occurs as microscopic crystals, the largest found is 6 by 20 micrometers. It is a radioactive mineral, but not fluorescent. Upon heating for dehydration it is found that the mineral loses some of its SO₂ at 600 to 800 °C.

Geologic occurrence

It occurs in the

oxidized zone Gossan (eiserner hut or eisenhut) is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein. In the ''classic'' gossan or iron cap all that remains is iron oxides and quartz, often i ...

of vanadium-poor Colorado Plateau-type uranium deposits of Utah and Arizona. It occurs in association with

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. ...

jarosite Jarosite is a basic hydrous sulfate of potassium and ferric iron (Fe-III) with a chemical formula of KFe3(SO4)2(OH)6. This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides. Jarosite is often produced as a byproduct duri ...

limonite Limonite () is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·H2O, although this is not entirely accurate as the ratio of oxide to hydroxid ...

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 ...

clay mineral Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces. Clay minerals ...

s and

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dea ...

ized wood at the Jomac mine, Utah. Coconinite was first described in 1966 for occurrences in the Huskon Mines,

Cameron Cameron may refer to: People * Clan Cameron, a Scottish clan * Cameron (given name), a given name (including a list of people with the name) * Cameron (surname), a surname (including a list of people with the name) ;Mononym * Cam'ron (born 197 ...

, Cameron District and the Sun Valley Mine,

Vermillion Cliffs The Vermilion Cliffs are the second "step" up in the five-step Grand Staircase of the Colorado Plateau, in northern Arizona and southern Utah. They extend west from near Page, Arizona, for a considerable distance, in both Arizona and Utah. o ...

District,

. It was named for Coconino County.

References

{{reflist Iron(III) minerals Aluminium minerals Uranium(VI) minerals Phosphate minerals Monoclinic minerals Minerals in space group 15