From Surf Wiki (app.surf) — the open knowledge base

Aheylite

Phosphate mineral

Field	Value
name	Aheylite
image	Aheylite-Cassiterite-177845.jpg
imagesize	170px
caption	Size: 3.5 × 2.3 × 0.8 cm. Translucent ~0.2 cm spheres of aheylite are perched on dark cassiterite, together with elongated quartz crystals.
category	Phosphate minerals
formula	(Fe2+,Zn)Al6(OH)8(PO4)4·4(H2O)
IMAsymbol	Ahe
strunz	8.DD.15
system	Triclinic
Unknown space group
unit cell	a = 7.885, b = 10.199
c = 7.672 [Å]; α = 110.84°
β = 115.12°, γ = 67.51°; Z = 1
color	Very pale blue, pale green, to blue-green
habit	Interlocked crystals in felted and matted aggregates forming botryoidal, spherulitic masses; radiating, prismatic groups
cleavage	Perfect {001}, {010} good
fracture	Hackly to splintery
tenacity	Brittle
mohs	5 to 5.5
luster	Porcelaneous to subvitreous
streak	White to greenish white
diaphaneity	Transparent in thin flakes
gravity	2.84
opticalprop	Biaxial (+)
refractive	~1.63
references

Unknown space group c = 7.672 [Å]; α = 110.84° β = 115.12°, γ = 67.51°; Z = 1 | length fast/slow = Aheylite is a rare phosphate mineral with formula (Fe2+Zn)Al6([OH)4|(PO4)2]2·4(H2O). It occurs as pale blue to pale green triclinic crystal masses. Aheylite was made the newest member of the turquoise group in 1984 by International Mineralogical Association Commission on New Minerals and Mineral Names.

Composition

The turquoise group has a basic formula of A0–1B6(PO4)4−x(PO3OH)x(OH)8·4H2O. This group contains five other minerals. In addition to aheylite: planerite, turquoise, faustite, 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, Oruro Department, Bolivia, and named for Allen V. Heyl (1918–2008), an economic geologist for the United States Geological Survey. It was eventually described by Eugene Foord and Joseph Taggart in 1998.

Occurrence

In addition to the type locality in Bolivia it has been reported from the Bali Lo prospect in the Capricorn Range, Western Australia and the Les Montmins Mine, Auvergne, France. It is a turquoise group mineral and occurs as a late hydrothermal phase in a tin deposit associated with variscite, vivianite, wavellite, cassiterite, sphalerite, pyrite and quartz in the type locality.

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 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

Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
[http://rruff.geo.arizona.edu/doclib/hom/aheylite.pdf Aheylite]. Handbook of Mineralogy
[http://www.mindat.org/min-60.html Aheylite]. Mindat.org
[http://rruff.info/uploads/MM62_93.pdf 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]
[http://www.webmineral.com/data/Aheylite.shtml Aheylite]. Webmineral

Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

iron(ii)-minerals aluminium-minerals phosphate-minerals hydroxide-minerals triclinic-minerals minerals-described-in-1998

Want to explore this topic further?

Ask Mako anything about Aheylite — get instant answers, deeper analysis, and related topics.

Research with Mako

Free with your Surf account

Content sourced from Wikipedia, available under CC BY-SA 4.0.

This content may have been generated or modified by AI. CloudSurf Software LLC is not responsible for the accuracy, completeness, or reliability of AI-generated content. Always verify important information from primary sources.

Report