Aheylite is a rare

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 ...

with formula ( Fe²⁺ Zn) Al₆ Ohydrogen.html"_;"title="oxygen.html"_;"title="oxygen">Ohydrogen">H)₄.html" ;"title="oxygen">O Ohydrogen">H)₄">(phosphorus.html" ;"title="hydrogen.html" ;"title="oxygen.html" ;"title=" Ohydrogen">H)₄">(phosphorus">PO₄)₂sub>2·4(H₂O)._It_occurs_as_pale_blue_to_pale_green_triclinic.html" ;"title="oxygen">Ohydrogen">H)₄">(phosphorus">PO₄)₂sub>2·4(H₂O). It occurs as pale blue to pale green triclinic">oxygen">Ohydrogen">H)₄">(phosphorus">PO₄)₂sub>2·4(H₂O). It occurs as pale blue to pale green triclinic crystal masses.Aheylite
Handbook of Mineralogy Aheylite was made the newest member of the

turquoise Turquoise is an opaque, blue-to-green mineral that is a hydrated phosphate of copper and aluminium, with the chemical formula . It is rare and valuable in finer grades and has been prized as a gemstone and ornamental stone for thousands of year ...

group in 1984 by International Mineralogical Association Commission on New Minerals and Mineral Names.

Composition

The turquoise group has a basic formula of A_0-1B₆(PO₄)_4−x(PO₃OH)_x(OH)₈·4H₂O. This group contains five other minerals. In addition to aheylite: planerite,

faustite The IMA approved mineral faustite, named after the American mineralogist and petrologist with the U.S. Geological Survey (USGS) Dr. George Tobias Faust, is a member of the triclinic turquoise group of hydrous phosphates with the following chemical ...

, chalcosiderite, and an unnamed Fe²⁺-Fe³⁺ analogue. Aheylite is distinguished in this group by having Fe²⁺ dominant in the A-site. The ideal aheylite has a formula of Fe²⁺Al₆(PO₄)₄(OH)₈·4H₂O. Its color is pale blue or green. With turquoise family the blue color is said to come from the octahedral coordination of Cu²⁺ in the absence of Fe³⁺.

Name and discovery

It was first described for an occurrence in the Huanuni mine,

Huanuni Huanuni is a town in the department of Oruro, Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia ...

Oruro Department Oruro (; Quechua: ''Uru Uru''; Aymara: ''Ururu'') is a department of Bolivia, with an area of . Its capital is the city of Oruro. According to the 2012 census, the Oruro department had a population of 494,178. Provinces of Oruro The departme ...

, Bolivia, and named for Allen V. Heyl (1918–2008), an economic geologist for the

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

.Aheylite
Mindat.org It was discovered by Eugene Foord and Joseph Taggart.Eugene E. Foord and Joseph E. Taggart, Jr., ''A reexamination of the turquoise group: the mineral aheylite, plane rite (redefined), turquoise and coeruleolactite,'' Mineralogical Magazine, February 1998, Vol. 62(1), pp. 93-111
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Occurrence

In addition to the type locality in Bolivia it has been reported from the Bali Lo prospect in the Capricorn Range,

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

and the Les Montmins Mine,

Auvergne Auvergne (; ; oc, label= Occitan, Auvèrnhe or ) is a former administrative region in central France, comprising the four departments of Allier, Puy-de-Dôme, Cantal and Haute-Loire. Since 1 January 2016, it has been part of the new region Au ...

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

. It is a

group mineral and occurs as a late

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

phase in a

tin Tin is a chemical element with the symbol Sn (from la, stannum) and atomic number 50. Tin is a silvery-coloured metal. Tin is soft enough to be cut with little force and a bar of tin can be bent by hand with little effort. When bent, t ...

deposit associated with

variscite Variscite is a hydrated aluminium phosphate mineral (). It is a relatively rare phosphate mineral. It is sometimes confused with turquoise; however, variscite is usually greener in color. The green color results from the presence of small amounts ...

vivianite Vivianite () is a hydrated iron phosphate mineral found in a number of geological environments. Small amounts of manganese Mn2+, magnesium Mg and calcium Ca may substitute for iron Fe2+ in the structure.Gaines et al (1997) Dana’s New Minera ...

wavellite Wavellite is an aluminium basic phosphate mineral with formula Al3( P O4)2(O H, F)3·5 H2O. Distinct crystals are rare, and it normally occurs as translucent green radial or spherical clusters. Discovery and occurrence Wavellite was first d ...

, cassiterite, sphalerite,

pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue giv ...

and

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 ...

in the type locality.Aheylite
Webmineral

Physical properties

It is found as an isolated mass of hemispheres and spheres clumped together. It has a vitreous to dull luster. It has a hackly to splintery fracture and it has a brittle tenacity. The hardness is about 5-5.5, and the

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest ...

is 2.84. As far as optical properties, it had thin flakes; ipale blue, green to blue-green color; it streaks white, and has a subvitreous luster.

References

{{Reflist Phosphate minerals Triclinic minerals