Ammonioalunite (original) (raw)

A valid IMA mineral species

About AmmonioaluniteHide

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Formula:

(NH4)Al3(SO4)2(OH)6

Name:

The name is derived from "alunite" since it is a member of the Alunite Sub-group. The "Ammonio" prefix designates that it is the (NH4)-dominant member of the sub-group.

This page provides mineralogical data about Ammonioalunite.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:203:1

90e94022-ae90-450f-8166-d8ea1dd59c98

IMA Classification of AmmonioaluniteHide

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Type description reference:

Altaner, S.P., Fitzpatrick, J.J., Krohn, M.D., Bethke, P.M., Hayba, D.O., Goss, J.A., Brown, Z.A. (1988) Ammonium in alunites. American Mineralogist: 73: 145-152.

Classification of AmmonioaluniteHide

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7.BC.10

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
B : Sulfates (selenates, etc.) with additional anions, without H2O
C : With medium-sized and large cations

30.2.4.6

30 : ANHYDROUS SULFATES CONTAINING HYDROXYL OR HALOGEN
2 : (AB)2(XO4)Zq

25.1.10

25 : Sulphates
1 : Sulphates of the alkali metals and ammonium

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Physical Properties of AmmonioaluniteHide

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Transparency:

Transparent, Translucent

Comment:

colorless in thin section.

Cleavage:

Perfect
perfect on {0001}(by analogy with the alunite group).

Density:

2.4 g/cm3 (Measured) 2.58 g/cm3 (Calculated)

Optical Data of AmmonioaluniteHide

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RI values:

_n_ω = 1.590(5) _n_ε = 1.602(5)

δ = 0.012

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Chemistry of AmmonioaluniteHide

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Mindat Formula:

(NH4)Al3(SO4)2(OH)6

Crystallography of AmmonioaluniteHide

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Cell Parameters:

a = 7.01 Å, c = 17.88 Å

Unit Cell V:

760.91 ų (Calculated from Unit Cell)

Morphology:

As rhombohedral crystals, to 20 μm, forming granular masses.

Comment:

Point Group: 3 2/m or 3m; Space Group: R3m or R3m. a

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Geological EnvironmentHide

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Type Occurrence of AmmonioaluniteHide

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General Appearance of Type Material:

As rhombohedral crystals, to 20 µm, forming granular masses.

Place of Conservation of Type Material:

National Museum of Natural History, Washington, D.C., USA, 145596.

Geological Setting of Type Material:

Formed in hot springs under very acid conditions, rich in ammonium and sulfate, poor in potassium, below 100 C.

Associated Minerals at Type Locality:

Reference:

Altaner, S.P., Fitzpatrick, J.J., Krohn, M.D., Bethke, P.M., Hayba, D.O., Goss, J.A., Brown, Z.A. (1988) Ammonium in alunites. American Mineralogist: 73: 145-152.

Synonyms of AmmonioaluniteHide

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Other Language Names for AmmonioaluniteHide

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Relationship of Ammonioalunite to other SpeciesHide

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Other Members of this group:

Common AssociatesHide

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Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

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Other InformationHide

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Health Risks:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for AmmonioaluniteHide

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References for AmmonioaluniteHide

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Reference List:

Altaner, S.P., Fitzpatrick, J.J., Krohn, M.D., Bethke, P.M., Hayba, D.O., Goss, J.A., Brown, Z.A. (1988) Ammonium in alunites. American Mineralogist: 73: 145-152.

Localities for AmmonioaluniteHide

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This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

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- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.