Lukrahnite (original) (raw)

A valid IMA mineral species

About LukrahniteHide

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Formula:

CaCuFe3+(AsO4)2(OH,H2O)2

Specific Gravity:

4.18 (Calculated)

Name:

For Ludger Krahn (b. 1957), mineral collector of Krefeld, Germany, who provided the initial specimen for study.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:11010:9

dcd00d3f-a1c5-45be-aeac-91a808086f66

IMA Classification of LukrahniteHide

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Classification of LukrahniteHide

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8.CG.20

8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
G : With large and medium-sized cations, RO4:H2O = 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 LukrahniteHide

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Hardness:

VHN25=630 kg/mm2 - Vickers

Density:

4.18 g/cm3 (Calculated)

Optical Data of LukrahniteHide

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RI values:

_n_α = 1.830 _n_β = 1.834 _n_γ = 1.890

δ = 0.060

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

Comments:

X=yellow
Y=Z=pale yellow
Orientation could not be determined

Chemistry of LukrahniteHide

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Mindat Formula:

CaCuFe3+(AsO4)2(OH,H2O)2

Crystallography of LukrahniteHide

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Class (H-M):

1 - Pinacoidal

Cell Parameters:

a = 5.457 Å, b = 5.539 Å, c = 7.399 Å
α = 68.43°, β = 68.9°, γ = 69.44°

Ratio:

a:b:c = 0.985 : 1 : 1.336

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Comments:

Tsumeb, Namibia. Data from the type description.

Geological EnvironmentHide

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Type Occurrence of LukrahniteHide

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General Appearance of Type Material:

Spherical aggregates up to 0.5 mm; individual grains < 30 microns.

Place of Conservation of Type Material:

Mineralogical Institute, University of Bochum, Germany.

Associated Minerals at Type Locality:

Synonyms of LukrahniteHide

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Other Language Names for LukrahniteHide

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Simplified Chinese:羟砷铁铜钙石 (in part)

Relationship of Lukrahnite 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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IR Spectrum:

IR spectrum similar to gatrellite.

Notes:

Slowly soluble in warm dilute HCl.

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 LukrahniteHide

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References for LukrahniteHide

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Reference List:

Krause, W., Blass, G., Bernhardt, H.-J., Effenberger, H. (2001) Lukrahnite, CaCuFe3+(AsO4)2[(H2O)(OH)], the calcium analogue of gartrellite. Neues Jahrbuch für Mineralogie - Monatshefte, 2001. 481-492

Localities for LukrahniteHide

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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.