Edwardsite (original) (raw)

A valid IMA mineral species

About EdwardsiteHide

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Formula:

Cu3Cd2(SO4)2(OH)6 · 4H2O

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

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Long-form identifier:

mindat:1:1:39682:4

6807c540-69f4-4660-a5fa-c5270479e19e

IMA Classification of EdwardsiteHide

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IMA Formula:

Cu3Cd2(SO4)2(OH)6 · 4H2O

Type description 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

Classification of EdwardsiteHide

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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

31.6.10.

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

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 EdwardsiteHide

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Comment:

Approximate value.

Cleavage:

Perfect
Excellent cleavage parallel to {100}.

Fracture:

Irregular/Uneven

Density:

3.53 g/cm3 (Calculated)

Optical Data of EdwardsiteHide

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RI values:

_n_α = 1.740 _n_β = 1.762(4) _n_γ = 1.770

δ = 0.030

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

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

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Mindat Formula:

Cu3Cd2(SO4)2(OH)6 · 4H2O

Crystallography of EdwardsiteHide

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Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

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)

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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X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Geological EnvironmentHide

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Type Occurrence of EdwardsiteHide

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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:

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: 39–53.

Synonyms of EdwardsiteHide

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Common AssociatesHide

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Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

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Fluorescence of EdwardsiteHide

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Other InformationHide

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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

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References for EdwardsiteHide

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Reference List:

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

Localities for EdwardsiteHide

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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.