Huemulite

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title: "Huemulite" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["triclinic-minerals", "sodium-minerals", "magnesium-minerals", "vanadate-minerals", "hydrate-minerals", "minerals-in-space-group-2"] description: "Mineral" topic_path: "general/triclinic-minerals" source: "https://en.wikipedia.org/wiki/Huemulite" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Mineral ::

::data[format=table title="Infobox mineral"]

Field	Value
name	Huemulite
category	Oxide mineral
image	Huemulite.jpg
formula	Na4Mg(V10O28)·24H2O
IMAsymbol	Hml
strunz	4.HG.10
dana	47.2.3.1
system	Triclinic
symmetry	P (no. 2)
unit cell	a = 9.0453(2) Å
b = 11.3337(3) Å
c = 11.7372(8) Å
α = 105.223(7)°
β = 97.383(7)°
γ = 100.790(7)°; Z = 1
color	Yellowish orange to orange
mohs	2.5 to 3
luster	Dull
refractive	nα = 1.679(3)
nβ = 1.734(3)
nγ = 1.742(2)
opticalprop	Biaxial (-)
birefringence	δ = 0.063
2V	25° to 30° (measured)
dispersion	r v strong
pleochroism	Visible
fluorescence	Not fluorescent
streak	Yellow
gravity	2.39 g/cm3
melt	500 C
solubility	Soluble in water
diaphaneity	Translucent
references
::

| name = Huemulite | category = Oxide mineral | boxwidth = | boxbgcolor = | image = Huemulite.jpg | imagesize = | caption = | formula = Na4Mg(V10O28)·24H2O | IMAsymbol = Hml | molweight = | strunz = 4.HG.10 | dana = 47.2.3.1 | system = Triclinic | symmetry = P (no. 2) | unit cell = a = 9.0453(2) Å b = 11.3337(3) Å c = 11.7372(8) Å α = 105.223(7)° β = 97.383(7)° γ = 100.790(7)°; Z = 1 | color = Yellowish orange to orange | habit = | twinning = | cleavage = | fracture = | tenacity = | mohs = 2.5 to 3 | luster = Dull | polish = | refractive = nα = 1.679(3) nβ = 1.734(3) nγ = 1.742(2) | opticalprop = Biaxial (-) | birefringence = δ = 0.063 | 2V = 25° to 30° (measured) | dispersion = r v strong | pleochroism = Visible | fluorescence= Not fluorescent | absorption = | streak = Yellow | gravity = 2.39 g/cm3 | density = | melt = 500 C | fusibility = | diagnostic = | solubility = Soluble in water | diaphaneity = Translucent | other = | references = Huemulite is a mineral with formula Na4Mg(V10O28)·24H2O that is yellow to orange in color. It was first discovered in Argentina in 1959 and described in 1966. The mineral is named for the Huemul mine in which it was discovered.

Occurrence and properties

Huemulite is yellowish orange to orange and bright in color.

Huemulite is a member of the pascoite group.

Formation and synthesis

In Argentina, the mineral formed after mine tunnels were cut through Cu-U deposits in sandstone and conglomerate. The vanadium in huemulite is thought to originate from asphaltic material that occurs in association with the sandstone.

Huemulite can be synthesized by mixing stoichiometric proportions of vanadium pentoxide, magnesium carbonate, and sodium carbonate in cold water in a humid environment. The mixture is heated to dissolve the compounds which react with each other as CO2 is drawn off. The solution is then concentrated, excess vanadic acid is removed by filtration, and allowed to cool and crystallize.

Since huemulite dissolves easily in water, it can be recrystallized by evaporating the mineral solution. When evaporated slowly, the process creates well-formed crystals up to 5 mm and 15 to. In a more humid environment, fibrous crystals or acicular radial aggregates are formed.

Both recrystallized and synthetic huemulite have tabular habit.

Structure

Huemulite exhibits the triclinic crystal system with space group P and one formula unit per unit cell.

History

Huemulite was discovered in the area of Malargüe in Mendoza Province, Argentina. Further specimens were collected in the mine as well as the nearby Huemul and Agua Botada Sur mines. In 1963, a preliminary report on the mineral was presented to the II Argentine Geological Congress. In 1964, the unit cell was measured at Yale University by Linares and H. Winchell and the mineral's chemical and physical properties were checked by C. E. Gordillo and R. O. Toubes.

Synthetic huemulite was deposited by Gordillo in the Museo de Mineralogía of the Universidad Nacional de Córdoba. No type specimens were designated by them, however, a type specimen was donated by Linares to the National Museum of Natural History in Washington, D.C. Unfortunately, during a 2011 study, the only mineral detected similar to huemulite was lasalite. It was determined that Gordillo et al. most likely used fully hydrated huemulite in chemical analysis and partially dehydrated huemulite in determining the mineral's powder X-ray diffraction.

Analysis

Huemulite in its natural form is too fine-grained for accurate study of its physical and optical properties; however, it can readily be recrystallized after dissolving the mineral in water. As far as can be determined, both recrystallized and synthetic huemulite are identical to natural specimens.

References

;Bibliography

References

1. Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
2. Gordillo, p. 12.
3. "Huemulite". Mindat.
4. [https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Huemulite Mineralienatlas]
5. (1 June 2011). "The Crystal Structure of the Elusive Huemulite". The Canadian Mineralogist.
6. "Huemulite Mineral Data".
7. "Huemulite". Mineral Data Publishing.
8. It melts at {{convert. 500. C. F to become a [[Phase transition. red liquid]]. Huemulite dissolves readily in cold water to produce an orange-yellow [[Solution (chemistry)
9. The [[crystal structure]] consists of decavanadate anions (V₁₀O₂₈)⁶⁻ linked by an interstitial complex of isolated [Mg(H₂O)₆]²⁺ and an infinite zigzag chain of [Na₄(H₂O)₁₄]⁴⁺. There are a further four isolated H₂O groups, two of which are positionally disordered.Colombo, p. 849.
10. The first specimen was collected in 1959 by V. Angelelli of the Geology Department of [[National Atomic Energy Commission
11. Gordillo, pp. 2–3.
12. The mineral was named ''huemulite'' after the Huemul mine in which it was discovered. On May 19, 1965, the mineral and name were approved by the Commission on New Minerals and Mineral Names of the [[International Mineralogical Association
13. Colombo, p. 850.
14. Colombo, p. 855.
15. Colombo, p. 857.
16. Gordillo, pp. 4–5.
17. Gordillo, p. 5.

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