Co-described with jolliffeite. Found as small, discrete, anhedral grains, with clausthalite and some unidentified selenides of Bi and Pb-Bi-Ag, within 'pitchblende'.

Optically quite similar to jolliffeite. Could represent a Se analogue of either cobaltite or glaucodot.

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Unique IdentifiersHide

Mindat ID:

52065

Long-form identifier:

mindat:1:1:52065:2

IMA Classification of UM1991-19-Se:AsCoHide

IMA status notes:

Unnamed (probably valid)

First published:

1991

Physical Properties of UM1991-19-Se:AsCoHide

Lustre:

Metallic

Transparency:

Opaque

Colour:

White

Hardness:

3 - 3½ on Mohs scale

Hardness Data:

Estimated

Tenacity:

Brittle

Cleavage:

None Observed

Fracture:

Sub-Conchoidal

Density:

7.1 g/cm³ (Calculated)

Optical Data of UM1991-19-Se:AsCoHide

Anisotropism:

slightly more anisotropic than jolliffeite

Chemistry of UM1991-19-Se:AsCoHide

Mindat Formula:

(Co,Ni)AsSe

Element Weights:

Element	% weight
Se	37.103 %
As	35.205 %
Co	27.692 %

Calculated from ideal end-member formula.

Elements listed:

As, Co, Ni, Se - search for minerals with similar chemistry

Crystallography of UM1991-19-Se:AsCoHide

Crystal System:

Isometric

Class (H-M):

m3 (2/m 3) - Diploidal

Space Group:

Pm3

Cell Parameters:

a = 5.831 Å

Unit Cell V:

198.26 Å³ (Calculated from Unit Cell)

Morphology:

Crystals rare or unknown

Comment:

probably not orthorhombic

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
2.916 Å	(50)
2.602 Å	(100)
2.378 Å	(80)
2.062 Å	(30)
1.757 Å	(80)
1.617 Å	(40)
1.559 Å	(50)

Comments:

the pattern couldn't be indexed; it differs from that of synthetic CoAsSe

Synonyms of UM1991-19-Se:AsCoHide

Unnamed (Co Arsenide-Selenide)

Relationship of UM1991-19-Se:AsCo to other SpeciesHide

Member of:

Cobaltite Group

Other Members of Cobaltite Group:

Andrieslombaardite	RhSbS	Iso. 2 3 : P2₁ 3
Changchengite	IrBiS	Iso. 2 3 : P2₁ 3
Cobaltite	CoAsS	Orth. mm2 : Pca2₁
Gersdorffite	NiAsS	Iso. 2 3 : P2₁ 3
Guixiangite	NiBiS	Iso. 2 3 : P2₁ 3
Hollingworthite	(Rh,Pt,Pd)AsS	Iso. m3 (2/m 3) : Pa3
Irarsite	(Ir,Ru,Rh,Pt)AsS	Iso. m3 (2/m 3) : Pa3
Jolliffeite	NiAsSe	Iso. m3 (2/m 3) : Pa3
Kalungaite	PdAsSe	Iso. m3 (2/m 3) : Pa3
Maslovite	PtBiTe	Iso. 2 3 : P2₁ 3
Mayingite	IrBiTe	Iso. m3 (2/m 3) : Pa3
Michenerite	PdBiTe	Iso. 2 3 : P2₁ 3
Milotaite	PdSbSe	Iso. 2 3 : P2₁ 3
Padmaite	PdBiSe	Iso. 4 3 2
Platarsite	Pt(As,S)₂	Iso. m3 (2/m 3) : Pa3
Testibiopalladite	PdSbTe	Iso.
Tolovkite	IrSbS	Iso.
Ullmannite	NiSbS	Iso. 2 3 : P2₁ 3
Willyamite	CoSbS

Fluorescence of UM1991-19-Se:AsCoHide

In UV light:

Not fluorescent in UV

Other InformationHide

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 UM1991-19-Se:AsCoHide

mindat.org URL:

https://www.mindat.org/min-52065.html
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References for UM1991-19-Se:AsCoHide

Reference List:

Cabri, Louis J., Laflamme, H. Gilles, Robert, Andrew C., Criddle, Alan J,, Hulbert, Larry J. (1991) Jolliffeite and unnamed CoAsSe; two new arsenoselenides from the north shore of Lake Athabasca, Saskatchewan. The Canadian Mineralogist, 29 (3) 411-418

Maasha, L. (1994): Selenium-bearing sulfarsenides of the cobaltite-gersdorffite series from deposits of Bu-Azzer district (Morocco). Zapiski Vserossiiskogo Mineralogicheskogo Obshchestva 123, 64-68 (in Russian).

Smith, D. G.W.; Nickel, E. H. (2007) A System of Codification for Unnamed Minerals: Report of the Subcommittee for Unnamed Minerals of the IMA Commission on New Minerals, Nomenclature and Classification. The Canadian Mineralogist, 45 (4). 983-990 doi:10.2113/gscanmin.45.4.983

Localities for UM1991-19-Se:AsCoHide

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

- 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.


Canada
Saskatchewan Lake Athabasca ⓘ Fish Hook Bay Mine	Cabri et al. (1991)

Morocco
Drâa-Tafilalet Region ⓘ Bou Azzer mining district	Vinogradova +5 other references

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