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Edwardsite

A valid IMA mineral species
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03273250017272007821313.jpg
Edwardsite, etc.

Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia
08195440017778260365728.jpg
Edwardsite

Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia
06625000017272007831638.jpg
Edwardsite

Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia
07478420017362825785856.jpg
Edwardsite, etc.

Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia
01390440017757660644244.jpg
Edwardsite

Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia
02460870017362825791490.jpg
Edwardsite

Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia
03273250017272007821313.jpg
Edwardsite, etc.

Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia
01113890017758300451286.jpg
Edwardsite

Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia
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About EdwardsiteHide

Formula:
Cu3Cd2(SO4)2(OH)6 · 4H2O
Colour:
Pale blue
Lustre:
Vitreous
Hardness:
3
Specific Gravity:
3.53 (Calculated)
Crystal System:
Monoclinic
Name:
Named in 2010 by P. Elliott, J. Brugger, and T. Caradoc-Davies in honor of Dr. Austin Burton Edwards (15 August 1909, Caulfield, Victoria, Australia - 8 October 1960, Rome, Italy), mineralogist and petrologist from 1934-1960 at CSIRO, for his contribution to the earth sciences, in particular, studies of the geology, geochemistry and mineralogy of Australian ore deposits. He published 18 papers on Broken Hill geology and mineralogy.
One of the rare secondary Cd minerals.

May be confused with Cd-bearing varieties of christelite.


Unique IdentifiersHide

Mindat ID:
39682
Long-form identifier:
mindat:1:1:39682:4

Similar NamesHide

IMA Classification of EdwardsiteHide

Classification of EdwardsiteHide

Strunz-mindat (2026):
7.DD.30

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
D : With only medium-sized cations; sheets of edge-sharing octahedra
Dana 8th ed.:
31.6.10.

31 : HYDRATED SULFATES CONTAINING HYDROXYL OR HALOGEN
6 : (AB)5(XO4)2Zq·xH2O

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
EdwIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of EdwardsiteHide

Lustre:
Vitreous
Transparency:
Transparent
Colour:
Pale blue
Streak:
White
Hardness:
3 on Mohs scale
Comment:
Approximate value.
Tenacity:
Brittle
Cleavage:
Perfect
Excellent cleavage parallel to {100}.
Fracture:
Irregular/Uneven
Density:
3.53 g/cm3 (Calculated)
Comment:
Not measured

Optical Data of EdwardsiteHide

Type:
Biaxial (-)
RI values:
nα = 1.74 nβ = 1.762(4) nγ = 1.77
2V:
Measured: 62°
Max. Birefringence:
δ = 0.030
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.

Surface Relief:
Very High (positive)
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 biaxial acute bisectrix (Bxa) interference figure - the conoscopic view for a grain cut perpendicular to the acute bisectrix, using this mineral's 2V. The two small white dots mark the melatopes - the points where the two optic axes emerge - and are shown only when they fall within the field of view. The coloured bands are isochromatics, and the dark bands are isogyres.

Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Optical Extinction:
X = b, Y ~ a, Z ~ c, with inclined extinction
Pleochroism:
Non-pleochroic
Comments:
Negative elongation (i.e. length-fast).

Refractive indices were obtained in white light using Cargille immersion liquids.

Chemistry of EdwardsiteHide

Mindat Formula:
Cu3Cd2(SO4)2(OH)6 · 4H2O
Element Weights:
Element% weight
O36.842 %
Cd28.761 %
Cu24.388 %
S8.204 %
H1.805 %

Calculated from ideal end-member formula.
O
Cd
Cu
S
H
Elements listed:
Cd, Cu, H, O, S - search for minerals with similar chemistry

Crystallography of EdwardsiteHide

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 10.863(2) Å, b = 13.129(3) Å, c = 11.169(2) Å
β = 113.04(3)°
Ratio:
a:b:c = 0.827 : 1 : 0.851
Unit Cell V:
1,465.86 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Flattened on {100} and often elongated along [010], with predominant crystal forms {100}, {001} and possibly {043}, with minor {010} plus other minor prisms and domes.

Crystal StructureHide

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IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0014597EdwardsiteElliot P, Brugger J, Caradoc-Davies T (2010) Description and crystal structure of a new mineral, edwardsite, Cu3Cd2(SO4)2(OH)6*4H2O, from Broken Hill, New South Wales, Australia Mineralogical Magazine 74 39-532010Block 14 Opencut, Broken Hill, Australia0293
CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Stage 7: Great Oxidation Event<2.4
47a : [Near-surface hydration of prior minerals]
47b : [Sulfates and sulfites]

Type Occurrence of EdwardsiteHide

Type Locality:
ⓘ Block 14 opencut, Broken Hill, Broken Hill district, Yancowinna Co., New South Wales, Australia
General Appearance of Type Material:
Druses of tabular and bladed crystals up to 0.06 mm in size.
Place of Conservation of Type Material:
Holotype specimen is deposited in the South Australian Museum, Adelaide, South Australia, (registration number G32703).
Geological Setting of Type Material:
Ore stockpile from a Ag-Pb-Zn deposit.
Associated Minerals at Type Locality:
ChristeliteNiedermayrite
Reference:
Elliott, P., Brugger, J., Caradoc-Davies, T. (2010) Description and crystal structure of a new mineral, edwardsite, Cu3Cd2(SO4)2(OH)6·4H2O, from Broken Hill, New South Wales, Australia. Mineralogical Magazine, 74 (1) 39-53 doi:10.1180/minmag.2010.074.1.39

Synonyms of EdwardsiteHide

Other Language Names for EdwardsiteHide

German:Edwardsit

Common AssociatesHide

Associations Based on Photo Data:
1 photo of Edwardsite associated with CadsulfohiteCd2(SO4)(OH)2
1 photo of Edwardsite associated with GermaniteCu13Fe2Ge2S16
1 photo of Edwardsite associated with GalenaPbS
1 photo of Edwardsite associated with QuartzSiO2
1 photo of Edwardsite associated with CerussitePbCO3
1 photo of Edwardsite associated with LauraniiteCu6Cd2(SO4)2(OH)12 · 5H2O

Related Minerals - Strunz-mindat GroupingHide

7.DD.AsagiiteNiCu4(SO4)2(OH)6 · 6H2OMon. 2/m : P21/b
7.DD.05FelsőbányaiteAl4(SO4)(OH)10 · 4H2OMon. 2 : P21
7.DD.07LlantenesiteCu6Al[SeO4](OH)12Cl · 3H2OTrig. 3m : P31c
7.DD.10LangiteCu4(SO4)(OH)6 · 2H2OMon. m
7.DD.10FehriteMgCu4(SO4)2(OH)6 · 6H2OMon. 2/m : P21/b
7.DD.10PosnjakiteCu4(SO4)(OH)6 · H2OMon. m : Pm
7.DD.10WroewolfeiteCu4(SO4)(OH)6 · 2H2OMon. m : Pm
7.DD.10GobeliniteCoCu4(SO4)2(OH)6 · 6H2OMon. 2/m : P21/m
7.DD.15KobyasheviteCu5(SO4)2(OH)6 · 4H2OTric. 1 : P1
7.DD.15SpangoliteCu6Al(SO4)(OH)12Cl · 3H2OTrig. 3m : P31c
7.DD.15'Unnamed (Dimorph of Devilline)'CaCu4(SO4)2(OH)6 · 3H2OMon. 2/m : P21/b
7.DD.20KtenasiteZnCu4(SO4)2(OH)6 · 6H2OMon. 2/m : P21/b
7.DD.25ChristeliteCu2Zn3(SO4)2(OH)6 · 4H2OTric. 1 : P1
7.DD.30NiedermayriteCdCu4(SO4)2(OH)6 · 4H2OMon. 2/m : P21/m
7.DD.30SerpieriteCa(Cu2+,Zn2+)4(S6+O4)2(OH)6 · 3H2OMon. 2/m : B2/b
7.DD.30CampigliaiteMn2+Cu4(SO4)2(OH)6 · 4H2OMon. 2 : B2
7.DD.30OrthoserpieriteCa(Cu,Zn)4(SO4)2(OH)6 · 3H2OOrth. mm2 : Pca21
7.DD.30DevillineCaCu4(SO4)2(OH)6 · 3H2OMon. 2/m : P21/b
7.DD.35ShigaiteMn6Al3(OH)18[Na(H2O)6](SO4)2 · 6H2OTrig. 3 : R3
7.DD.35Zincaluminite(Zn1-xAlx)(SO4)x/2(OH)2 · nH2O
7.DD.35ZincowoodwarditeZn1-xAlx(OH)2[SO4]x/2 · nH2OTrig.
7.DD.35NatroglaucoceriniteZn6Al3(OH)18[Na(H2O)6](SO4)2 · 6H2OHex.
7.DD.35Hydrowoodwardite(Cu1-xAlx)(OH)2[SO4]x/2 · nH2OTrig. 3m(32/m) : R3m
7.DD.35Honessite(Ni1-xFe3+x)(OH)2[SO4]x/2 · nH2OTrig.
7.DD.35Carrboydite(Ni1-xAlx)(SO4)x/2(OH)2 · nH2OHex.
7.DD.35Glaucocerinite(Zn1-xAlx)(OH)2(SO4)x/2 · nH2OHex.
7.DD.35WermlanditeMg7Al2(OH)18[Ca(H2O)6][SO4]2 · 6H2OTrig. 3m(32/m) : P3c1
7.DD.35NikischeriteFe2+6Al3(OH)18[Na(H2O)6](SO4)2 · 6H2OTrig. 3 : R3
7.DD.35Hydrohonessite(Ni1-xFe3+x)(OH)2(SO4)x/2 · nH2OHex.
7.DD.35WoodwarditeCu1-xAlx(OH)2(SO4)x/2 · nH2OTrig. 3m(32/m) : R3m
7.DD.35MotukoreaiteMg6Al3(OH)18[Na(H2O)6][SO4]2 · 6H2OTrig. 3m(32/m) : R3m
7.DD.35Mountkeithite[(Mg1-xFe3+x)(OH)2][SO4]x/2 · nH2OHex.
7.DD.40Lawsonbauerite(Mn2+,Mg)9Zn4(SO4)2(OH)22 · 8H2OMon. 2/m : P21/b
7.DD.40Torreyite(Mg,Mn2+)7◻2Mn2+2Zn4(SO4)2(OH)22 · 8H2OMon. 2/m : P21/b
7.DD.40IsseliteCu6(SO4)(OH)10(H2O)4 · H2OOrth. mm2 : Pmn21
7.DD.45MooreiteMg9◻2Mn2Zn4(SO4)2(OH)26 · 8H2OMon. 2/m : P2/b
7.DD.45Hodgesmithite(Cu,Zn)6Zn(SO4)2(OH)10 · 3H2OTrig. 3 : P3
7.DD.47LahnsteiniteZn4(SO4)(OH)6 · 3H2OTric. 1 : P1
7.DD.50NamuwiteZn4(SO4)(OH)6 · 4H2OTrig. 3 : P3
7.DD.50Minohlite(Cu,Zn)7(SO4)2(OH)10 · 8H2OHex.
7.DD.52LauraniiteCu6Cd2(SO4)2(OH)12 · 5H2OMon. 2/m : P21/b
7.DD.55BechereriteZn7Cu(OH)13[(SiO(OH)3(SO4)]Trig. 3 : P3
7.DD.60Ramsbeckite(Cu,Zn)15(SO4)4(OH)22 · 6H2OMon. 2/m
7.DD.65VonbezingiteCa6Cu3(SO4)3(OH)12 · 2H2OMon. 2/m : P21/b
7.DD.70RedgilliteCu6(SO4)(OH)10 · H2OMon. 2/m : P21/b
7.DD.75NickelalumiteNiAl4(SO4)(OH)12(H2O)3Mon. 2/m
7.DD.75KyrgyzstaniteZnAl4(SO4)(OH)12 · 3H2OMon. 2/m : P21/b
7.DD.75ChalcoalumiteCuAl4(SO4)(OH)12 · 3H2OMon. 2 : P21
7.DD.80Schulenbergite(Cu,Zn)7(SO4)2(OH)10 · 3H2OTrig. 3
7.DD.80'UM1992-30-SO:CCuHZn'(Zn,Cu)7(SO4,CO3)2(OH)10 · 3H2OTrig. 3 : P3
7.DD.80ThérèsemagnaniteNaCo4(SO4)(OH)6Cl · 6H2OTrig. 3 : P3
7.DD.80GuarinoiteZn6(SO4)(OH)10 · 5H2OHex.
7.DD.85MontetrisaiteCu6(SO4)(OH)10 · 2H2OOrth. mm2 : Cmc21

Fluorescence of EdwardsiteHide

In UV light:
Not fluorescent

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 EdwardsiteHide

References for EdwardsiteHide

Localities for EdwardsiteHide

Showing 5 localities.

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.
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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.
Australia (TL)
 
  • New South Wales
    • Yancowinna Co.
      • Broken Hill district
        • Broken Hill
Elliott et al. (2010)
Greece
 
  • Attica
    • East Attica
      • Lavreotiki
        • Agios Konstantinos (Kamariza)
          • Kamariza Mines (Kamareza Mines)
Rieck et al. (2018)
        • Km 3
          • Kaminiza mines
Rieck et al. (2018) +1 other reference
        • Sounion
          • Cato Sounio mines
Rieck et al. (2018)
Namibia
 
  • Oshikoto Region
    • Tsumeb
Joy Desor specimen
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