Eckhardite
A valid IMA mineral species
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About Eckhardite
Formula:
(Ca,Pb)Cu2+Te6+O5(H2O)
Colour:
Light bluish green
Lustre:
Sub-Adamantine, Vitreous
Hardness:
2 - 3
Specific Gravity:
4.644 (Calculated)
Crystal System:
Monoclinic
Name:
Named in honor of Colonel (retired) Eckhard D. Stuart (b. 1939), a prolific American field collector and micro collector of Jackson, Mississippi, and Mancos, Colorado, who discovered the species.
This page provides mineralogical data about Eckhardite.
Unique Identifiers
Mindat ID:
43850
Long-form identifier:
mindat:1:1:43850:0
IMA Classification of Eckhardite
Approved
IMA Formula:
(Ca,Pb2+)Cu2+Te6+O5·H2O
Approval year:
2012
Type description reference:
Kampf, A. R., Mills, S. J., Housley, R. M., Rossman, G. R., Marty, J., Thorne, B. (2013) Lead-tellurium oxysalts from Otto Mountain near Baker, California: XI. Eckhardite, (Ca,Pb)Cu2+Te6+O5(H2O), a new mineral with HCP stair-step layers. American Mineralogist, 98 (8) 1617-1623 doi:10.2138/am.2013.4529
Classification of Eckhardite
7.CC.90
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
C : With medium-sized and large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with 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 |
|---|---|---|
| Ehd | 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 Eckhardite
Sub-Adamantine, Vitreous
Transparency:
Transparent
Colour:
Light bluish green
Streak:
Very pale bluish green
Hardness:
2 - 3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Likely but not observed on {101}
Likely but not observed on {101}
Fracture:
Irregular/Uneven
Density:
4.644 g/cm3 (Calculated)
Optical Data of Eckhardite
Type:
Biaxial (-)
RI values:
nα = 1.770 nβ = 1.860 nγ = 1.895(5)
2V:
Measured: 61.2° (5)
Max. Birefringence:
δ = 0.125
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:
Moderate
Pleochroism:
Visible
Comments:
: Z = light blue-green, X = colorless, Y = very pale blue-green. Absorption: Z < Y < X
Chemistry of Eckhardite
Mindat Formula:
(Ca,Pb)Cu2+Te6+O5(H2O)
Element Weights:
Crystallography of Eckhardite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 8.1606(8) Å, b = 5.3076(6) Å, c = 11.4412(15) Å
β = 101.549(7)°
β = 101.549(7)°
Ratio:
a:b:c = 1.538 : 1 : 2.156
Unit Cell V:
485.52 ų (Calculated from Unit Cell)
Z:
4
Comment:
Space Group: P21/n.
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0020260 | Eckhardite | Kampf A R, Mills S J, Housley R M, Rossman G R, Marty J, Thorne B (2013) Lead-tellurium oxysalts from Otto Mountain near Baker, California: XI. Eckhardite, (Ca,Pb)Cu2+Te6+O5(H2O), a new mineral with HCP stair-step layers American Mineralogist 98 1617-1623 | 2013 | Otto Mountain near Baker, California, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.94 Å | (100) |
| 3.287 Å | (80) |
| 2.645 Å | (89) |
| 2.485 Å | (48) |
| 2.245 Å | (46) |
| 1.809 Å | (40) |
| 1.552 Å | (42) |
| 1.530 Å | (43) |
Reference:
Kampf, A. R., Mills, S. J., Housley, R. M., Rossman, G. R., Marty, J., Thorne, B. (2013) Lead-tellurium oxysalts from Otto Mountain near Baker, California: XI. Eckhardite, (Ca,Pb)Cu2+Te6+O5(H2O), a new mineral with HCP stair-step layers. American Mineralogist, 98 (8) 1617-1623 doi:10.2138/am.2013.4529
Comments:
From Type Description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47e : [Vanadates, chromates, manganates] |
Type Occurrence of Eckhardite
Co-Type Localities:
General Appearance of Type Material:
As needles or blades elongated along [010] and
flattened on {101}, to 150 μm; in sub-radial to radial aggregates.
flattened on {101}, to 150 μm; in sub-radial to radial aggregates.
Place of Conservation of Type Material:
Type material is deposited in the collections of the Mineral Sciences Department, Natural History Museum of Los Angeles County, Los Angeles, California, USA, catalogue numbers 62512 and 64011
Associated Minerals at Type Locality:
Reference:
Kampf, A. R., Mills, S. J., Housley, R. M., Rossman, G. R., Marty, J., Thorne, B. (2013) Lead-tellurium oxysalts from Otto Mountain near Baker, California: XI. Eckhardite, (Ca,Pb)Cu2+Te6+O5(H2O), a new mineral with HCP stair-step layers. American Mineralogist, 98 (8) 1617-1623 doi:10.2138/am.2013.4529
Synonyms of Eckhardite
Other Language Names for Eckhardite
Dutch:Eckhardiet
German:Eckhardit
Common Associates
Associations Based on Photo Data:
| 11 photos of Eckhardite associated with Markcooperite | Pb2(UO2)(TeO6) |
| 4 photos of Eckhardite associated with Khinite | Pb2+Cu2+3[Te6+O6](OH)2 |
| 4 photos of Eckhardite associated with Housleyite | Pb6CuTe6+4O18(OH)2 |
| 2 photos of Eckhardite associated with Hessite | Ag2Te |
| 2 photos of Eckhardite associated with Native Gold | Au |
| 2 photos of Eckhardite associated with Chlorargyrite | AgCl |
| 2 photos of Eckhardite associated with Thorneite | Pb6(Te6+2O10)(CO3)Cl2(H2O) |
| 1 photo of Eckhardite associated with Ottoite | Pb2TeO5 |
Related Minerals - Strunz-mindat Grouping
| 7.CC. | Cobaltoblödite | Na2Co(SO4)2 · 4H2O |
| 7.CC. | Andychristyite | PbCu2+Te6+O5(H2O) |
| 7.CC. | Ammoniovoltaite | (NH4)2Fe2+5Fe3+3Al(SO4)12(H2O)18 |
| 7.CC.05 | Krausite | KFe(SO4)2 · H2O |
| 7.CC.10 | Tamarugite | NaAl(SO4)2 · 6H2O |
| 7.CC.15 | Mendozite | NaAl(SO4)2 · 11H2O |
| 7.CC.15 | Kalinite | KAl(SO4)2 · 11H2O |
| 7.CC.20 | Alum-(Na) | NaAl(SO4)2 · 12H2O |
| 7.CC.20 | Lonecreekite | (NH4)Fe3+(SO4)2 · 12H2O |
| 7.CC.20 | Alum-(K) | KAl(SO4)2 · 12H2O |
| 7.CC.20 | Tschermigite | (NH4)Al(SO4)2 · 12H2O |
| 7.CC.20 | Lanmuchangite | Tl+Al(SO4)2 · 12H2O |
| 7.CC.25 | Zincovoltaite | K2Zn5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Voltaite | K2Fe2+5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Magnesiovoltaite | K2Mg5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Pertlikite | K2(Fe2+,Mg)2(Mg,Fe3+)4Fe3+2Al(SO4)12 · 18H2O |
| 7.CC.25 | Ammoniomagnesiovoltaite | (NH4)2Mg2+5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.30 | Kröhnkite | Na2Cu(SO4)2 · 2H2O |
| 7.CC.35 | Ferrinatrite | Na3Fe(SO4)3 · 3H2O |
| 7.CC.40 | Goldichite | KFe(SO4)2 · 4H2O |
| 7.CC.45 | Löweite | Na12Mg7(SO4)13 · 15H2O |
| 7.CC.50 | Nickelblödite | Na2Ni(SO4)2 · 4H2O |
| 7.CC.50 | Blödite | Na2Mg(SO4)2 · 4H2O |
| 7.CC.50 | Changoite | Na2Zn(SO4)2 · 4H2O |
| 7.CC.55 | Leonite | K2Mg(SO4)2 · 4H2O |
| 7.CC.55 | Mereiterite | K2Fe(SO4)2 · 4H2O |
| 7.CC.60 | Nickelpicromerite | K2Ni(SO4)2 · 6H2O |
| 7.CC.60 | Nickelboussingaultite | (NH4)2Ni(SO4)2 · 6H2O |
| 7.CC.60 | Katerinopoulosite | (NH4)2Zn(SO4)2 · 6H2O |
| 7.CC.60 | Picromerite | K2Mg(SO4)2 · 6H2O |
| 7.CC.60 | Cyanochroite | K2Cu(SO4)2 · 6H2O |
| 7.CC.60 | Mohrite | (NH4)2Fe(SO4)2 · 6H2O |
| 7.CC.60 | Boussingaultite | (NH4)2Mg(SO4)2 · 6H2O |
| 7.CC.65 | Polyhalite | K2Ca2Mg(SO4)4 · 2H2O |
| 7.CC.70 | Leightonite | K2Ca2Cu(SO4)4 · 2H2O |
| 7.CC.75 | Amarillite | NaFe(SO4)2 · 6H2O |
| 7.CC.80 | Konyaite | Na2Mg(SO4)2 · 5H2O |
| 7.CC.85 | Wattevilleite | Na2Ca(SO4)2 · 4H2O (?) |
| 7.CC.85 | Xocolatlite | Ca2Mn4+2(Te6+O6)2 · H2O |
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.
Internet Links for Eckhardite
mindat.org URL:
https://www.mindat.org/min-43850.html
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References for Eckhardite
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2013) New minerals and nomenclature modifications approved in 2013. CNMNC Newsletter No 16. Mineralogical Magazine, 77 (6) 2695-2709 doi:10.1180/minmag.2013.077.6.01
Kampf, A. R., Mills, S. J., Housley, R. M., Rossman, G. R., Marty, J., Thorne, B. (2013) Lead-tellurium oxysalts from Otto Mountain near Baker, California: XI. Eckhardite, (Ca,Pb)Cu2+Te6+O5(H2O), a new mineral with HCP stair-step layers. American Mineralogist, 98 (8) 1617-1623 doi:10.2138/am.2013.4529
Localities for Eckhardite
Showing 5 localities.
symbol to view information about a locality.
The Locality List
- 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).
All localities listed without proper references should be considered as questionable.
USA (TL) | |
| Williams et al. (2013) |
| Williams et al. (2013) |
| MarekC personal collection | |
| Miyawaki et al. (2019) +1 other reference |
| Coolbaugh et al. (2020) |
Quick NavTopAbout EckharditeUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Bird Nest drift, Otto Mountain, Baker, Soda Mountains, Silver Lake Mining District, San Bernardino County, California, USA