Melanarsite (original) (raw)

A valid IMA mineral species

About MelanarsiteHide

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Formula:

K3Cu7Fe3+O4(AsO4)4

Specific Gravity:

4.39 (Calculated)

Crystal System:

Monoclinic

Name:

The name reflects belonging of the mineral to arsenates and its black colour (colour name taken from Greek)

New structure type: heteropolyhedral pseudo-framework comprises distorted Cu(1-3)O6 and (Fe,Cu)O6 octahedra, and As(1-3)O4 tetrahedra. There are tunnels and voids occupied by two independent K atoms ([8]K & [7]K).

Melanarsite is the second K-Cu-Fe-As mineral after obradovicite-KCu.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:46427:7

94e2496f-9fbb-45b6-9b97-bdf7c9a19353

IMA Classification of MelanarsiteHide

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Type description reference:

Pekov, Igor V., Zubkova, Natalia V., Yapaskurt, Vasiliy O., Polekhovsky, Yury S., Vigasina, Marina F., Belakovskiy, Dmitry I., Britvin, Sergey N., Sidorov, Evgeny G., Pushcharovsky, Dmitry Y. (2016) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VI. Melanarsite, K3Cu7Fe3+O4(AsO4)4. Mineralogical Magazine, 80 (5) 855-867 doi:10.1180/minmag.2016.080.027

Classification of MelanarsiteHide

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8.BH.75

8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
H : With medium-sized and large cations, (OH,etc.):RO4 = 1:1

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 MelanarsiteHide

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Streak:

Dark green with an olive hue

Hardness:

VHN100=203 - Vickers

Fracture:

Irregular/Uneven

Density:

4.39 g/cm3 (Calculated)

Optical Data of MelanarsiteHide

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RI values:

_n_α = 1.800(1) _n_γ = 1.910(1)

δ = 0.110

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

Reflectivity:

Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 11.4%.
R1 shown in black, R2 shown in red

Colour in reflected light:

Dark grey

Comments:

Observed in the thinnest particles, is strong with Z (very dark greyish-green) > X (green to pale green).

Comments:

Optical sign, β, and 2V not determined.

Chemistry of MelanarsiteHide

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Mindat Formula:

K3Cu7Fe3+O4(AsO4)4

Crystallography of MelanarsiteHide

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Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

Cell Parameters:

a = 11.4763(9) Å, b = 16.620(2) Å, c = 10.1322(8) Å
β = 105.078(9)°

Ratio:

a:b:c = 0.691 : 1 : 0.61

Unit Cell V:

1,866.04 ų (Calculated from Unit Cell)

Morphology:

Tabular to prismatic crystals up to 0.4 mm; clusters; forming crust

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Comments:

From Type Description.

Geological EnvironmentHide

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Type Occurrence of MelanarsiteHide

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General Appearance of Type Material:

Tabular to prismatic crystals up to 0.4 mm, separate or combined in clusters up to 1 mm across or in interrupted crusts up to 0.02 x 1 x 1 cm covering basalt scoria.

Place of Conservation of Type Material:

Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 4550/1

Geological Setting of Type Material:

Associated Minerals at Type Locality:

Reference:

Pekov, I.V., Zubkova, N.V., Yapaskurt, V.O., Polekhovsky, Yu.S., Vigasina, M.F., Belakovskiy, D.I., Britvin, S.N., Sidorov, E.G., Pushcharovsky, D.Y. (2016) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VI. Melanarsite, K3Cu7Fe^3+O4(AsO4)4. Mineralogical Magazine, 80, 855-867.

Synonyms of MelanarsiteHide

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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 MelanarsiteHide

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References for MelanarsiteHide

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Reference List:

Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2014) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC), CNMNC Newsletter No. 22. Mineralogical Magazine, 78 (5) 1241-1248 doi:10.1180/minmag.2014.078.5.10

Pekov, Igor V., Zubkova, Natalia V., Yapaskurt, Vasiliy O., Polekhovsky, Yury S., Vigasina, Marina F., Belakovskiy, Dmitry I., Britvin, Sergey N., Sidorov, Evgeny G., Pushcharovsky, Dmitry Y. (2016) New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. VI. Melanarsite, K3Cu7Fe3+O4(AsO4)4. Mineralogical Magazine, 80 (5) 855-867 doi:10.1180/minmag.2016.080.027

Localities for MelanarsiteHide

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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.