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Karlseifertite
A valid IMA mineral species
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About Karlseifertite
Formula:
Pb(Ga2Ge)(AsO4)2(OH)6
Colour:
yellow
Lustre:
Sub-Adamantine
Hardness:
4
Specific Gravity:
4.993 (Calculated)
Crystal System:
Trigonal
Member of:
Name:
The name karlseifertite honours the German mining engineer Karl Markus Seifert (1911–2000). Mr Seifert's professional career spanned nearly 50 years, much of which was spent as an engineer and prospector for mining companies in Namibia (South West Africa for most of that period). From 1963 to 1967, he was mining engineer for Tsumeb Corporation Ltd. (TCL), which operated the Tsumeb mine (Tsumcorp mine). Karl Seifert was well known for his expertise in geology and mineralogy, particularly with respect to mineral exploration. He also had a passion for mineral collecting and assembled an extensive collection through his many diverse mining pursuits. The mineral named in his honour was found on specimens that he collected as mining engineer at Tsumeb.
Unique Identifiers
Mindat ID:
471227
Long-form identifier:
mindat:1:1:471227:1
IMA Classification of Karlseifertite
Approved
IMA Formula:
Pb2+(Ga2Ge)(As5+O4)2(OH)6
Classification of Karlseifertite
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
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
B : Sulfates (selenates, etc.) with additional anions, without H2O
C : With medium-sized and large cations
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Karl | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Karlseifertite
Sub-Adamantine
Transparency:
Transparent
Colour:
Yellow
Streak:
Pale yellow
Hardness:
4 on Mohs scale
Comment:
by analogy with other members of the dussertite group
Tenacity:
Brittle
Fracture:
Irregular/Uneven
Density:
4.993 g/cm3 (Calculated)
Optical Data of Karlseifertite
Type:
Uniaxial (+)
RI values:
nω = 1.890(5) nε = 1.894
Max. Birefringence:
δ = 0.004
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Weak
Comments:
Pleochroism is slight with O (light yellow) and E (pale yellow): O > E.
Comments:
the calculated value of ε is 1.894.
Chemistry of Karlseifertite
Mindat Formula:
Pb(Ga2Ge)(AsO4)2(OH)6
Element Weights:
Crystallography of Karlseifertite
Crystal System:
Trigonal
Class (H-M):
3m(32/m) - Hexagonal Scalenohedral
Space Group:
R3m
Setting:
R3m
Cell Parameters:
a = 7.2814(7) Å, c = 17.108(1) Å
Ratio:
a:c = 1 : 2.35
Unit Cell V:
785.52 ų (Calculated from Unit Cell)
Z:
3
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.919 Å | (50) |
| 3.644 Å | (29) |
| 3.073 Å | (100) |
| 2.853 Å | (19) |
| 2.540 Å | (19) |
| 2.280 Å | (27) |
| 1.973 Å | (27) |
| 1.821 Å | (23) |
Type Occurrence of Karlseifertite
General Appearance of Type Material:
rosettes of thin hexagonal plates (bounded by the {001} and {100} forms) up to about 0.2 mm in diameter and usually less than 0.01 mm thick.
Place of Conservation of Type Material:
Type material is deposited in the collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue number 76334 (holotype) and 76335 (cotype)
Geological Setting of Type Material:
secondary oxidation-zone mineral found on fracture surfaces in germanite–chalcocite ore.
Associated Minerals at Type Locality:
Other Language Names for Karlseifertite
Dutch:Karlseifertiet
German:Karlseifertit
Relationship of Karlseifertite to other Species
Member of:
Other Members of Dussertite Group:
| Arsenocrandallite | CaAl3(AsO4)(AsO3OH)(OH)6 | Trig. 3m(32/m) |
| Arsenoflorencite-(Ce) | CeAl3(AsO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Arsenoflorencite-(La) | LaAl3(AsO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| 'Arsenoflorencite-(Nd)' | NdAl3(AsO4)2(OH)6 | Trig. |
| Arsenogorceixite | BaAl3(AsO4)(AsO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
| Arsenogoyazite | SrAl3(AsO4)(AsO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
| 'Arsenowaylandite' | BiAl3(AsO4)2(OH)6 | Trig. |
| Dussertite | BaFe3+3(AsO4)(AsO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
| Graulichite-(Ce) | CeFe3+3(AsO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Graulichite-(La) | LaFe3+3(AsO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Philipsbornite | PbAl3(AsO4)(AsO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
| Segnitite | PbFe3+3AsO4(AsO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
Common Associates
Associations Based on Photo Data:
| 1 photo of Karlseifertite associated with Germanite | Cu13Fe2Ge2S16 |
| 1 photo of Karlseifertite associated with Chalcocite | Cu2S |
Related Minerals - Strunz-mindat Grouping
| 7.BC. | Viskontite | Pb5Cu2(SO4)3(SeO3)(OH)6 |
| 7.BC. | Zincochenite | Pb4Zn(SO4)2(OH)6 |
| 7.BC. | D'Ansite-(Mn) | Na21Mn2+(SO4)10Cl3 |
| 7.BC. | D'Ansite-(Fe) | Na21Fe2+(SO4)10Cl3 |
| 7.BC. | Acmonidesite | (NH4,K,Pb)8NaFe2+4(SO4)5Cl8 |
| 7.BC. | Adranosite | (NH4)4NaAl2(SO4)4Cl(OH)2 |
| 7.BC. | Chromviskontite | Pb5Cu2(CrO4)3(SeO3)(OH)6 |
| 7.BC. | Backite | Pb2AlTeO6Cl |
| 7.BC. | Adranosite-(Fe) | (NH4)4NaFe3+2(SO4)4Cl(OH)2 |
| 7.BC. |
Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia