Keyite
A valid IMA mineral species
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About Keyite
Formula:
Cu2+3Zn4Cd2(AsO4)6 · 2H2O
Colour:
Deep sky blue, blue
Hardness:
3½ - 4
Specific Gravity:
5.106
Crystal System:
Monoclinic
Member of:
Name:
Named in honor of Charles Locke Key (b. 1935 - d. 2021), For prominent U.S. mineral dealer, who supplied the mineral for investigation. The mineral ludlockite is also named, in part, after him.
Isostructural with:
Unique Identifiers
Mindat ID:
2191
Long-form identifier:
mindat:1:1:2191:9
GUID
(UUID V4):
(UUID V4):
4db8196e-b312-4716-bb71-5203864822ef
Classification of Keyite
Approved
Approval year:
1975
First published:
1977
Type description reference:
8.CA.50
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
A : With small and large/medium cations
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
A : With small and large/medium cations
40.2.18.
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
2 : AB2(XO4)2·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
2 : AB2(XO4)2·xH2O
20.3.22
20 : Arsenates (also arsenates with phosphate, but without other anions)
3 : Arsenates of Zn, Cd or Hg
20 : Arsenates (also arsenates with phosphate, but without other anions)
3 : Arsenates of Zn, Cd or Hg
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 |
---|---|---|
Key | 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 Keyite
Transparency:
Translucent
Colour:
Deep sky blue, blue
Streak:
Pale blue
Hardness:
3½ - 4 on Mohs scale
Cleavage:
Distinct/Good
{001}
{001}
Density:
5.106 g/cm3 (Measured) 4.95 g/cm3 (Calculated)
Optical Data of Keyite
Type:
Biaxial
RI values:
nα = 1.800 nγ = 1.870
Max Birefringence:
δ = 0.070
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:
Moderate
Dispersion:
r > v, strong
Optical Extinction:
Y = b; X ∧ c = 11°, variable with wavelength.
Chemical Properties of Keyite
Formula:
Cu2+3Zn4Cd2(AsO4)6 · 2H2O
IMA Formula:
(◻0.5Cu0.5)CuCdZn2(AsO4)3 · H2O
Crystallography of Keyite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 11.654(3) Å, b = 12.780(5) Å, c = 6.840(3) Å
β = 99.11°
β = 99.11°
Ratio:
a:b:c = 0.912 : 1 : 0.535
Unit Cell V:
1005.8 ų
Z:
2
Morphology:
Prismatic [001] to tabular {010}, commonly tapering or showing sub-parallel stacking on {010}. Dominant forms observed on SEM photos {010), {110}, {210}, {011}, and perhaps {201}.
Twinning:
None observed.
Comment:
space group I2/a
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) |
---|---|---|---|---|---|---|---|
0005498 | Keyite | Cooper M A, Hawthorne F C (1996) The crystal structure of keyite, Cu3(Zn,Cu)4Cd2(AsO4)6(H2O)2, an oxysalt mineral with essential cadmium The Canadian Mineralogist 34 623-630 | 1996 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
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Radiation - Copper Kα
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
2.795 Å | (very very strong) |
3.29 Å | (very strong) |
2.876 Å | (very strong) |
6.41 Å | (medium strong) |
1.644 Å | (medium strong) |
3.15 Å | (medium) |
1.700 Å | (medium) |
Comments:
Tsumeb, Namibia. Data from the type description.
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 7: Great Oxidation Event | <2.4 |
45a : [Sulfates, arsenates, selenates, antimonates] | |
46 : Near-surface hydrothermal alteration of minerals (see also #22) | |
47a : [Near-surface hydration of prior minerals] | |
47d : [Arsenates, antimonates, selenates, bismuthinates] |
Type Occurrence of Keyite
General Appearance of Type Material:
Small blue prisms in cavities in tennantite ore.
Place of Conservation of Type Material:
The Natural History Museum, London, England, numbers 1973,236 (holotype), 1975,660.
Harvard University, Cambridge, Massachusetts, USA, number 119917.
Harvard University, Cambridge, Massachusetts, USA, number 119917.
Associated Minerals at Type Locality:
Reference:
Embrey, P.G., Fejer, E.E., Clark, A.M. (1977) Keyite: a new mineral from Tsumeb. The Mineralogical Record: 8: 87-90.
Synonyms of Keyite
Other Language Names for Keyite
Relationship of Keyite to other Species
Member of:
Other Members of this group:
Alluaudite | (Na,Ca)Mn2+(Fe3+,Mn2+,Fe2+,Mg)2(PO4)3 | Mon. 2/m : B2/b |
Alluaudite-Ca□ | ◻4Ca4Mn2+4Fe3+8(PO4)12 | Mon. 2/m : B2/b |
Alluaudite-Na□ | ◻4Na4Mn2+4Fe3+8(PO4)12 | Mon. 2/m : B2/b |
Arseniopleite | NaCaMnMn2(AsO4)3 | Mon. 2/m |
Badalovite | Na2Mg2Fe(AsO4)3 | Mon. 2/m : B2/b |
Bradaczekite | NaCu4(AsO4)3 | Mon. 2/m : B2/b |
Calciohatertite | NaNaCa(CaFe3+)(AsO4)3 | Mon. 2/m : B2/b |
Calciojohillerite | NaCaMg3(AsO4)3 | Mon. 2/m : B2/b |
Camanchacaite | NaCaMg2[AsO4][AsO3(OH)]2 | Mon. 2/m : B2/b |
Canutite | NaMn3[AsO4][AsO3(OH)]2 | Mon. 2/m : B2/b |
Caryinite | (Na,Pb)(Ca,Na)CaMn2+2(AsO4)3 | Mon. 2/m |
Erikapohlite | Cu3(Zn,Cu,Mg)4Ca2(AsO4)6 · 2H2O | Mon. 2/m : B2/m |
Ferroalluaudite | (Na,Ca)Fe2+(Fe3+,Mn2+,Fe2+)2(PO4)3 | Mon. 2/m : B2/b |
Ferroalluaudite-NaNa | Na4Na4Fe2+4Fe3+8(PO4)12 | Mon. 2/m : B2/m |
Ferrohagendorfite | NaCaFe2+Fe2+2(PO4)3 | Mon. |
Groatite | NaCaMn2(PO4)[PO3(OH)]2 | Mon. 2/m : B2/b |
Hagendorfite | NaCaMn2+Fe2+2(PO4)3 | Mon. 2/m : B2/b |
Hagendorfite-NaNa | NaNaFe2+(Mn2+,Mn3+)(PO4)3 (?) | Mon. 2/m : B2/b |
Hatertite | Na2(Ca,Na)(Fe3+,Cu)2(AsO4)3 | Mon. 2/m : B2/b |
Johillerite | Na(Mg,Zn)3Cu(AsO4)3 | Mon. 2/m : B2/b |
Khrenovite | Na3Fe3+2(AsO4)3 | Mon. 2/m : B2/b |
Maghagendorfite | (Na,◻)MgMn2+(Fe2+,Fe3+)2(PO4)3 | Mon. 2/m |
Magnesiocanutite | NaMnMg2[AsO4]2[AsO2(OH)2] | Mon. 2/m : B2/b |
Magnesiohatertite | (Na,Ca)2Ca(Mg,Fe3+)2(AsO4)3 | Mon. 2/m : B2/b |
Nickenichite | Na0.8Ca0.4Cu0.4(Mg,Fe)3(AsO4)3 | Mon. 2/m : B2/b |
O'Danielite | Na(Zn,Mg)3(AsO4)(AsO3OH)2 | Mon. 2/m : B2/b |
Paraberzeliite | NaCa2Mg2(AsO4)3 | Mon. 2/m : B2/b |
Unnamed (Na-Mg Arsenate Hydroxyarsenate) | NaMg3(AsO4)(AsO3OH)2 | Mon. 2/m : B2/b |
Unnamed (Na-Zn-H Arsenate Hydrxyarsenate) | Na(Na0.6Zn0.4)Zn2(H0.6AsO4)(AsO3OH)2 | Mon. 2/m : B2/b |
Varulite | NaCaMn2+Mn2+2(PO4)3 | Mon. 2/m : B2/b |
Yazganite | NaFe3+2(Mg,Mn2+)(AsO4)3 · H2O | Mon. 2/m : B2/b |
Zhanghuifenite | Na3Mn4Mg2Al(PO4)6 | Mon. 2/m |
Zincobradaczekite | NaZn2Cu2(AsO4)3 | Mon. 2/m : B2/b |
Common Associates
Associated Minerals Based on Photo Data:
28 photos of Keyite associated with Zincolivenite | CuZn(AsO4)(OH) |
5 photos of Keyite associated with Adamite | Zn2(AsO4)(OH) |
2 photos of Keyite associated with Chalcocite | Cu2S |
2 photos of Keyite associated with Bayldonite | PbCu3(AsO4)2(OH)2 |
2 photos of Keyite associated with Schultenite | Pb(HAsO4) |
1 photo of Keyite associated with Tennantite Subgroup | Cu6(Cu4C2+2)As4S12S |
1 photo of Keyite associated with Niedermayrite | CdCu4(SO4)2(OH)6 · 4H2O |
1 photo of Keyite associated with Thometzekite | PbCu2+2(AsO4)2 · 2H2O |
Related Minerals - Strunz-mindat Grouping
8.CA. | Davidlloydite | Zn3(AsO4)2 · 4H2O | Tric. 1 : P1 |
8.CA. | Apexite | NaMg(PO4) · 9H2O | Tric. 1 : P1 |
8.CA. | Brandãoite | BeAl2(PO4)2(OH)2(H2O)5 | Tric. 1 : P1 |
8.CA.05 | Fransoletite | Ca3Be2(PO4)2(PO3OH)2 · 4H2O | Mon. 2/m : P21/b |
8.CA.05 | Parafransoletite | Ca3Be2(PO4)2(PO3OH)2 · 4H2O | Tric. 1 : P1 |
8.CA.10 | Ehrleite | Ca4Be3Zn2(PO4)6 · 9H2O | Tric. 1 : P1 |
8.CA.15 | Faheyite | Be2Mn2+Fe3+2(PO4)4 · 6H2O | Trig. 3 2 : P31 2 1 |
8.CA.20 | Gainesite | Na(Na,K)(Be,Li)Zr2(PO4)4 · 1.5-2H2O | Tet. 4mm : I41md |
8.CA.20 | Mccrillisite | NaCs(Be,Li)Zr2(PO4)4 · 1-2H2O | Tet. 4/mmm (4/m 2/m 2/m) : I41/amd |
8.CA.20 | Selwynite | NaK(Be,Al)Zr2(PO4)4 · 2H2O | Tet. 4/mmm (4/m 2/m 2/m) : I41/amd |
8.CA.25 | Pahasapaite | Li8(Ca,Li,K)10.5Be24(PO4)24 · 38H2O | Iso. 2 3 : I2 3 |
8.CA.30 | Hopeite | ZnZn2(PO4)2 · 4H2O | Orth. mmm (2/m 2/m 2/m) : Pnma |
8.CA.30 | Arsenohopeite | Zn3(AsO4)2 · 4H2O | Orth. mmm (2/m 2/m 2/m) : Pnma |
8.CA.30 | Nizamoffite | Mn2+Zn2(PO4)2(H2O)4 | Orth. mmm (2/m 2/m 2/m) : Pbcm |
8.CA.30 | Unnamed (Mg-analogue of Hopeite) | Mg3(PO4)2 · 4H2O | |
8.CA.35 | Warikahnite | Zn3(AsO4)2 · 2H2O | Tric. 1 : P1 |
8.CA.40 | Phosphophyllite | Zn2Fe(PO4)2 · 4H2O | Mon. 2/m : P21/b |
8.CA.42 | Steinmetzite | Zn2Fe3+(PO4)2(OH) · 3H2O | Tric. 1 : P1 |
8.CA.45 | Parascholzite | CaZn2(PO4)2 · 2H2O | Mon. |
8.CA.45 | Scholzite | CaZn2(PO4)2 · 2H2O | Orth. mmm (2/m 2/m 2/m) : Pbcm |
8.CA.55 | Pushcharovskite | K0.6Cu18[AsO2(OH)2]4[AsO3OH]10(AsO4)(OH)9.6 · 18.6H2O | Tric. |
8.CA.60 | Prosperite | Ca2Zn4(AsO4)4 · H2O | Mon. |
8.CA.65 | Gengenbachite | KFe3+3(PO3OH)4[PO2(OH)2]2 · 6H2O | Trig. 3m : P3 1c |
8.CA.70 | Parahopeite | Zn3(PO4)2 · 4H2O | Tric. 1 : P1 |
8.CA.70 | Reaphookhillite | MgZn2(PO4)2 · 4H2O | Tric. 1 : P1 |
8.CA.75 | Stergiouite | CaZn2(AsO4)2 · 4H2O | Mon. m : Pb |
8.CA.80 | Limousinite | BaCa[Be4P4O16] · 6H2O | Mon. 2/m : P21/b |
8.CA.85 | Minjiangite | BaBe2(PO4)2 | Hex. 6/mmm (6/m 2/m 2/m) : P6/mmm |
8.CA.85 | Wilancookite | (Ba5Li2◻)Ba6Be24P24O96 · 26H2O | Iso. 2 3 : I2 3 |
Fluorescence of Keyite
Not fluorescent.
Other Information
Thermal Behaviour:
Blackens on heating.
Notes:
Soluble in concentrated HCl or HNO3.
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 Keyite
mindat.org URL:
https://www.mindat.org/min-2191.html
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References for Keyite
Reference List:
Localities for Keyite
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).
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.
All localities listed without proper references should be considered as questionable.
Greece | |
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Namibia (TL) | |
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Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia