Engelhauptite
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About Engelhauptite
Formula:
KCu3(V2O7)(OH)2Cl
Colour:
Yellow-brown to brown, typically with an olive green hue
Lustre:
Vitreous
Specific Gravity:
3.86 (Calculated)
Crystal System:
Hexagonal
Name:
Named after the German amateur mineralogist and mineral collector Bernd Engelhaupt (born 1946), who found the mineral.
Structurally related to volborthite, and can be considered as its analogue resulting from the replacement of H2O molecules by the equal amounts of K+ and Cl− ions (Pekov et al 2015).
Classification of Engelhauptite
Approved
Approval Year:
2013
Physical Properties of Engelhauptite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Yellow-brown to brown, typically with an olive green hue
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Irregular/Uneven
Density:
3.86 g/cm3 (Calculated)
Optical Data of Engelhauptite
Type:
Uniaxial (+)
RI values:
nω = 1.978() nε = 2.021(4)
Max Birefringence:
δ = 0.043
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Very High
Chemical Properties of Engelhauptite
Formula:
KCu3(V2O7)(OH)2Cl
Crystallography of Engelhauptite
Crystal System:
Hexagonal
Class (H-M):
6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal
Space Group:
P63/mmc
Setting:
P63/mmc
Cell Parameters:
a = 5.922(2) Å, c = 14.513(5) Å
Ratio:
a:c = 1 : 2.451
Unit Cell V:
440.78 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Spherulites (up to 0.2 mm in diameter) and bunches consisting of rough spindle-shaped crystals elongated parallel to [0001].
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.32 | (98) |
| 4.224 | (17) |
| 2.979 | (100) |
| 2.759 | (19) |
| 2.565 | (18) |
| 2.424 | (18) |
| 1.765 | (16) |
| 1.481 | (14) |
Comments:
From Type Description.
Type Occurrence of Engelhauptite
General Appearance of Type Material:
Spherulites (up to 0.2 mm in diameter) and bunches consisting of rough spindle-shaped crystals. The crystals are up to 0.12 mm long and up to 0.04 mm thick.
Place of Conservation of Type Material:
Type material is deposited in the collections of the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 4309/1
Geological Setting of Type Material:
In cavities in nepheline basalts.
Associated Minerals at Type Locality:
Synonyms of Engelhauptite
Other Language Names for Engelhauptite
German:UM K-Cu-Al-Cl-Vanadat
Common Associates
Associated Minerals Based on Photo Data:
| Volborthite | 1 photo of Engelhauptite associated with Volborthite on mindat.org. |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
References for Engelhauptite
Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Pekov, I.V., Siidra, O.I., Chukanov, N.V. , Yapaskurt, V.O., Britvin, S.N., Krivovichev, S.V., Schüller, W. and Ternes, B. (2013) Engelhauptite, IMA 2013-009. CNMNC Newsletter No. 16, August 2013, page 2702; Mineralogical Magazine, 77, 2695-2709.
Blaß, G. & Kruijen, F. (2014): Die Neufunde aus der Vulkaneifel. Mineralien-Welt 25 (2), 66-81 (in German).
Pekov, I.V., Siidra, O.I., Chukanov, N.V., Yapaskurt, V.O., Britvin, S.N., Krivovichev, S.V., Schüller, W., Ternes, B. (2015): Engelhauptite, KCu3(V2O7)(OH)2 Cl, a new mineral species from Eifel, Germany. Mineralogy and Petrology, 109, 705-711.
Internet Links for Engelhauptite
mindat.org URL:
https://www.mindat.org/min-43875.html
Please feel free to link to this page.
Please feel free to link to this page.
External Links:
Mineral Dealers:
Localities for Engelhauptite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for 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).
All localities listed without proper references should be considered as questionable.
Germany (TL) | |
| Pekov, I.V., Siidra, O.I., Chukanov, N.V., Yapaskurt, V.O., Britvin, S.N., Krivovichev, S.V., Schüller, W. and Ternes, B. (2013) Engelhauptite, IMA 2013-009. CNMNC Newsletter No. 16, August 2013, page 2702; Mineralogical Magazine, 77, 2695-2709; Blaß, G. & Kruijen, F. (2014): Die Neufunde aus der Vulkaneifel. Mineralien-Welt 25 (2), 66-81 (in German); Pekov, I.V., Siidra, O.I., Chukanov, N.V., Yapaskurt, V.O., Britvin, S.N., Krivovichev, S.V., Schüller, W., Ternes, B. (2015): Engelhauptite, KCu3(V2O7)(OH)2 Cl, a new mineral species from Eifel, Germany. Mineralogy and Petrology, 109, 705-711. |
Kahlenberg, Oberstadtfeld, Daun, Rhineland-Palatinate, Germany