Keyite
A valid IMA mineral species
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About Keyite
Charles Key in 2011
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
Similar Names
IMA Classification of Keyite
Approved
IMA Formula:
(◻0.5Cu2+0.5)Cu2+Cd2+Zn2+2(As5+O4)3·H2O
Approval year:
1975
First published:
1977
Classification of Keyite
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 for Standard |
|---|---|---|
| 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 = 1.8 nγ = 1.87
Max. Birefringence:
δ = 0.070
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
Dispersion:
r > v, strong
Optical Extinction:
Y = b; X ∧ c = 11°, variable with wavelength.
Chemistry of Keyite
Mindat Formula:
Cu2+3Zn4Cd2(AsO4)6 · 2H2O
Element Weights:
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
Loading XRD data...
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:
Synonyms of Keyite
Other Language Names for Keyite
Relationship of Keyite to other Species
Member of:
Other Members of Alluaudite 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 (Mn-analogue of Alluaudite)' | (Na,Ca)Mn2+(Mn3+,Fe3+,Fe2+)2(PO4)3 | |
| 'Unnamed (Na-Mg Arsenate Hydroxyarsenate)' | NaMg3(AsO4)(AsO3OH)2 | Mon. 2/m : B2/b |
| 'Unnamed (Na-Zn-H Arsenate Hydroxyarsenate)' | 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
Associations Based on Photo Data:
| 29 photos of Keyite associated with Zincolivenite | CuZn(AsO4)(OH) |
| 5 photos of Keyite associated with Adamite | Zn2(AsO4)(OH) |
| 3 photos of Keyite associated with Bayldonite | PbCu3(AsO4)2(OH)2 |
| 2 photos of Keyite associated with Chalcocite | Cu2S |
| 1 photo of Keyite associated with Thometzekite | PbCu2+2(AsO4)2 · 2H2O |
| 1 photo of Keyite associated with Niedermayrite | CdCu4(SO4)2(OH)6 · 4H2O |
| 1 photo of Keyite associated with Tennantite Subgroup | Cu6(Cu4C2+2)As4S12S |
Related Minerals - Strunz-mindat Grouping
| 8.CA. | Apexite | NaMg(PO4) · 9H2O |
| 8.CA. | Brandãoite | BeAl2(PO4)2(OH)2(H2O)5 |
| 8.CA. | Davidlloydite | Zn3(AsO4)2 · 4H2O |
| 8.CA.05 | Parafransoletite | Ca3Be2(PO4)2(PO3OH)2 · 4H2O |
| 8.CA.05 | Fransoletite | Ca3Be2(PO4)2(PO3OH)2 · 4H2O |
| 8.CA.10 | Ehrleite | Ca4Be3Zn2(PO4)6 · 9H2O |
| 8.CA.15 | Faheyite | Be2Mn2+Fe3+2(PO4)4 · 6H2O |
| 8.CA.20 | Mccrillisite | NaCs(Be,Li)Zr2(PO4)4 · 1-2H2O |
| 8.CA.20 | Gainesite | Na(Na,K)(Be,Li)Zr2(PO4)4 · 1.5-2H2O |
| 8.CA.20 | Selwynite | NaK(Be,Al)Zr2(PO4)4 · 2H2O |
| 8.CA.25 | Pahasapaite | Li8(Ca,Li,K)10.5Be24(PO4)24 · 38H2O |
| 8.CA.30 | Nizamoffite | Mn2+Zn2(PO4)2(H2O)4 |
| 8.CA.30 | Arsenohopeite | Zn3(AsO4)2 · 4H2O |
| 8.CA.30 | Hopeite | ZnZn2(PO4)2 · 4H2O |
| 8.CA.35 | Warikahnite | Zn3(AsO4)2 · 2H2O |
| 8.CA.40 | Phosphophyllite | Zn2Fe 2+(PO4)2 · 4H2O |
| 8.CA.42 | Steinmetzite | Zn2Fe3+(PO4)2(OH) · 3H2O |
| 8.CA.45 | Parascholzite | CaZn2(PO4)2 · 2H2O |
| 8.CA.45 | Scholzite | CaZn2(PO4)2 · 2H2O |
| 8.CA.55 | Pushcharovskite | K0.6Cu18[AsO2(OH)2]4[AsO3OH]10(AsO4)(OH)9.6 · 18.6H2O |
| 8.CA.60 | Prosperite | Ca2Zn4(AsO4)4 · H2O |
| 8.CA.65 | Gengenbachite | KFe3+3(PO3OH)4[PO2(OH)2]2 · 6H2O |
| 8.CA.70 | Parahopeite | Zn3(PO4)2 · 4H2O |
| 8.CA.70 | Reaphookhillite | MgZn2(PO4)2 · 4H2O |
| 8.CA.75 | Stergiouite | CaZn2(AsO4)2 · 4H2O |
| 8.CA.80 | Limousinite | BaCa[Be4P4O16] · 6H2O |
| 8.CA.85 | Minjiangite | BaBe2(PO4)2 |
| 8.CA.85 | Wilancookite | (Ba5Li2◻)Ba6Be24P24O96 · 26H2O |
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
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Keyite
Reference List:
Clark, Andrew M., Embrey, Peter G., Fejer, Eva E. (1977) Keyite: a New Mineral from Tsumeb. The Mineralogical Record, 8 (3) 87-90
Fleischer, Michael, Cabri, Louis J., Pabst, and Adolf (1977) New mineral names. American Mineralogist, 62 (11-12) 1259-1262
Clark, Andrew M., Embrey, Peter G., Fejer, Eva E. (1977) Keyite: a New Mineral from Tsumeb. The Mineralogical Record, 8 (3) 87-90
Schlüter, Jochen, Malcherek, Thomas, Mihailova, Boriana, Gebhard, Georg (2013) The new mineral erikapohlite, Cu3(Zn,Cu,Mg)4Ca2(AsO4)6 · 2H2O, the Ca-dominant analogue of keyite, from Tsumeb, Namibia. Neues Jahrbuch für Mineralogie - Abhandlungen, 190 (3) 319-325 doi:10.1127/0077-7757/2013/0239
Localities for Keyite
Showing 3 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.
Greece | |
| Rieck (1999) |
| Rieck (1999) |
Namibia (TL) | |
| Rocks & Minerals: 62: 440. +1 other reference |
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Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia