Keckite
A valid IMA mineral species
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About Keckite
Formula:
CaMn2+(Fe3+Mn2+)Fe3+2(PO4)4(OH)3 · 7H2O
Colour:
Golden brown, orange brown
Lustre:
Sub-Vitreous, Resinous
Hardness:
4½
Specific Gravity:
2.6
Crystal System:
Monoclinic
Member of:
Name:
Named by Arno Mücke in 1979 in honor of Erich Keck (b. 1938) of Germany, mineral collector specializing in Hagendorf minerals. His large collection of Hagendorf minerals is now preserved at Mineralogische Staatssammlung, Munich, Germany.
A member of the jahnsite group which contains trivalent iron not only at the C site but also at the B site.
Note: According to Hochleitner & Fehr (2010), keckite from Hagendorf forms golden-yellow to orange fibrous crusts which are intimately associated with rockbridgeite-frondelite. Specimens showing distinct "keckite" crystals in collections were found to be always either jahnsite-(CaMnFe) or jahnsite-(CaMnMn).
Compare Jahnsite-(CaMnFe).
Possibly intermediate between Jahnsite-(CaMnMn) and Jahnsite-(CaMnFe) and not a valid species, requires investigation into valance state and occupancy of the Fe.
Note: According to Hochleitner & Fehr (2010), keckite from Hagendorf forms golden-yellow to orange fibrous crusts which are intimately associated with rockbridgeite-frondelite. Specimens showing distinct "keckite" crystals in collections were found to be always either jahnsite-(CaMnFe) or jahnsite-(CaMnMn).
Compare Jahnsite-(CaMnFe).
Possibly intermediate between Jahnsite-(CaMnMn) and Jahnsite-(CaMnFe) and not a valid species, requires investigation into valance state and occupancy of the Fe.
Unique Identifiers
Mindat ID:
2174
Long-form identifier:
mindat:1:1:2174:2
Similar Names
Classification of Keckite
The structure archetype of jahnsite group minerals, which includes the jahnsite and whiteite subgroups. Keckite is a special member of the jahnsite group that has additional cation ordering of its M2 site resulting in different dominant site occupants at each symmetrically unique M2 site. A similar situation is responsible for rittmannite.
IMA Classification of Keckite
Approved
IMA Formula:
CaMn2+(Fe3+,Mn2+)2Fe3+2(PO4)4(OH)3·7H2O
Approval year:
1977
First published:
1979
Type description reference:
8.DH.15
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
H : With large and medium-sized cations, (OH, etc.):RO4 < 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
H : With large and medium-sized cations, (OH, etc.):RO4 < 1:1
42.11.4.1
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
11 : (AB)3(XO4)2Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
11 : (AB)3(XO4)2Zq·xH2O
19.12.44
19 : Phosphates
12 : Phosphates of Mn
19 : Phosphates
12 : Phosphates of Mn
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 |
|---|---|---|
| Kec | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Keckite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Keckite
Sub-Vitreous, Resinous
Transparency:
Transparent, Translucent
Colour:
Golden brown, orange brown
Comment:
Possibly sore are red brown, but these tend to be other jahnsites.
Streak:
Yellow brown
Hardness:
4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
{001}, {100}
{001}, {100}
Fracture:
Irregular/Uneven, Splintery
Density:
2.6 g/cm3 (Measured) 2.682 g/cm3 (Calculated)
Comment:
Also D= 2.649
Optical Data of Keckite
Type:
Biaxial (-)
Dispersion:
weak to distinct
Optical Extinction:
X ^ c = 15-20 degrees
Pleochroism:
Strong
Comments:
X reddish brown, Y yellow, Z bright yellow
Comments:
Undulatory extinction; Birefringence probably similar to other jahnsites
Chemistry of Keckite
Mindat Formula:
CaMn2+(Fe3+Mn2+)Fe3+2(PO4)4(OH)3 · 7H2O
Element Weights:
Common Impurities:
Mg
Crystallography of Keckite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P2/b
Setting:
P2/a
Cell Parameters:
a = 15.02 Å, b = 7.19 Å, c = 19.74 Å
β = 110.5°
β = 110.5°
Ratio:
a:b:c = 2.089 : 1 : 2.745
Unit Cell V:
1,996.80 ų (Calculated from Unit Cell)
Morphology:
Tightly clustered bladed to stout crystals arranged in subparallel groups.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.3 Å | (80) |
| 4.98 Å | (50) |
| 4.63 Å | (30) |
| 3.51 Å | (50) |
| 2.86 Å | (100) |
| 2.59 Å | (40) |
| 2.34 Å | (30) |
| 1.879 Å | (40) |
Comments:
ICDD 33-289
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Keckite
General Appearance of Type Material:
Crusts of yellow-brown to golden brown indistinct crystals.
Geological Setting of Type Material:
Late stage oxidized mineralization in secondary phosphate-rich granite pegmatites.
Associated Minerals at Type Locality:
Synonyms of Keckite
Other Language Names for Keckite
Relationship of Keckite to other Species
Member of:
Other Members of Jahnsite Subgroup:
| 'Jahnsite-(CaFeFe)' | {Ca}{Fe2+}{Fe2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. |
| Jahnsite-(CaFeMg) | {Ca}{Fe2+}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
| 'Jahnsite-(CaMgMg)' | {Ca}{Mg}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O | |
| Jahnsite-(CaMnFe) | {Ca}{Mn2+}{Fe2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
| Jahnsite-(CaMnMg) | {Ca}{Mn2+}{(Mg,Fe2+)2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
| Jahnsite-(CaMnMn) | {Ca}{Mn2+}{Mn2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
| Jahnsite-(CaMnZn) | {Ca}{Mn2+}{Zn2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
| Jahnsite-(MnMnFe) | {Mn2+}{Mn2+}{Fe2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
| Jahnsite-(MnMnMg) | {Mn2+}{Mn2+}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
| Jahnsite-(MnMnMn) | {Mn2+}{Mn2+}{Mn2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P21/b |
| Jahnsite-(MnMnZn) | {Mn2+}{Mn2+}{Zn2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
| Jahnsite-(NaFeMg) | {Na}{Fe3+}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
| Jahnsite-(NaMnMg) | {(Na,Ca)}{(Mn2+,Fe3+)}{(Mg,Fe3+)2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
| Jahnsite-(NaMnMn) | {Na}{Mn2+}{(Mn2+,Fe3+)2}{Fe3+2}(PO4)4(OH)2 · 8H2O | Mon. 2/m : P2/b |
Common Associates
Associations Based on Photo Data:
| 5 photos of Keckite associated with Rockbridgeite | (Fe2+0.5Fe3+0.5)2Fe3+3(PO4)3(OH)5 |
| 5 photos of Keckite associated with Strunzite | Mn2+Fe3+2(PO4)2(OH)2 · 6H2O |
| 5 photos of Keckite associated with Strengite | FePO4 · 2H2O |
| 4 photos of Keckite associated with Phosphophyllite | Zn2Fe 2+(PO4)2 · 4H2O |
| 3 photos of Keckite associated with Kingsmountite | Ca3Mn2+FeAl4(PO4)6(OH)4 · 12H2O |
| 3 photos of Keckite associated with Scholzite | CaZn2(PO4)2 · 2H2O |
| 2 photos of Keckite associated with Cryptomelane | K(Mn4+7Mn3+)O16 |
| 1 photo of Keckite associated with Phosphosiderite | FePO4 · 2H2O |
| 1 photo of Keckite associated with Beraunite | Fe3+6(PO4)4O(OH)4 · 6H2O |
| 1 photo of Keckite associated with Schoonerite | ZnMn2+Fe2+2Fe3+(PO4)3(OH)2 · 9H2O |
Related Minerals - Strunz-mindat Grouping
| 8.DH. | Thebaite-(NH4) | (NH4)3Al(C2O4)(PO3OH)2(H2O) |
| 8.DH. | Whiteite-(MnMnMn) | Mn2+Mn2+Mn2+2Al2(PO4)4(OH)2 · 8H2O |
| 8.DH. | Ammoniotinsleyite | (NH4)Al2(PO4)2(OH) · 2H2O |
| 8.DH. | Bergbauerite | (H2O)2Mn2(Fe2Ti)(PO4)4(OH)2(H2O)10 · 4H2O |
| 8.DH. | Dendoraite-(NH4) | (NH4)2NaAl(C2O4)(PO3OH)2(H2O)2 |
| 8.DH. | Rowleyite | [Na(NH4,K)9Cl4][V5+,4+2(P,As)O8]6 · n[H2O,Na,NH4,K,Cl] |
| 8.DH. | Hochleitnerite | Mn2Ti3(PO4)4O2(H2O)2 · 14H2O |
| 8.DH. | Whiteite-(CaMnFe) | CaMnFe2Al2(PO4)4(OH)2 · 8H2O |
| 8.DH.05 | Minyulite | KAl2(PO4)2F · 4H2O |
| 8.DH.10 | Leucophosphite | KFe3+2(PO4)2(OH) · 2H2O |
| 8.DH.10 | Tinsleyite | KAl2(PO4)2(OH) · 2H2O |
| 8.DH.10 | Spheniscidite | (NH4,K)(Fe3+,Al)2(PO4)2(OH) · 2H2O |
| 8.DH.15 | Jahnsite-(CaMnFe) | {Ca}{Mn2+}{Fe2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(NaMnMn) | {Na}{Mn2+}{(Mn2+,Fe3+)2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(CaMnMg) | {Ca}{Mn2+}{(Mg,Fe2+)2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(CaMnMn) | {Ca}{Mn2+}{Mn2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(MnMnMg) | MnMnMg2Al2(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(CaMnZn) | {Ca}{Mn2+}{Zn2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(MnMnMg) | {Mn2+}{Mn2+}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(MnMnFe) | {Mn2+}{Mn2+}{Fe2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | 'Jahnsite-(CaFeFe)' | {Ca}{Fe2+}{Fe2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Rittmannite | {(Mn2+,Ca)}{Mn2+}{(Fe2+,Mn2+,Mg)2}{(Al,Fe3+)2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(NaMnMg) | {(Na,Ca)}{(Mn2+,Fe3+)}{(Mg,Fe3+)2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | 'Jahnsite-(CaMgMg)' | {Ca}{Mg}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(MnMnZn) | {Mn2+}{Mn2+}{Zn2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(CaMgMg) | CaMg3Al2(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(CaFeMg) | {Ca}{(Fe2+,Mn2+)}{Mg2}{Al2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(CaMnMg) | {Ca}{Mn2+}{Mg2}{Al2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(MnFeMg) | {(Mn2+,Ca)}{(Fe2+,Mn2+)}{Mg2}{Al2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(MnMnMn) | {Mn2+}{Mn2+}{Mn2+2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | 'Kaluginite' | (Mn2+,Ca)MgFe3+(PO4)2(OH) · 4H2O |
| 8.DH.15 | Jahnsite-(CaFeMg) | {Ca}{Fe2+}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Whiteite-(CaMnMn) | {Ca}{Mn2+}{Mn2}{Al2}(PO4)4(OH)2 · 8H2O |
| 8.DH.15 | Jahnsite-(NaFeMg) | {Na}{Fe3+}{Mg2}{Fe3+2}(PO4)4(OH)2 · 8H2O |
| 8.DH.20 | Segelerite | Ca2 Mg2 Fe3+2(PO4)4(OH)2 · 8H2O |
| 8.DH.20 | Lun'okite | (Mn,Ca)(Mg,Fe,Mn)Al(PO4)2OH · 4H2O |
| 8.DH.20 | Manganosegelerite | (Mn2+,Ca)(Mn2+,Fe2+,Mg)Fe3+(PO4)2(OH) · 4H2O |
| 8.DH.20 | Wilhelmvierlingite | CaMnFe3+(PO4)2(OH) · 2H2O |
| 8.DH.20 | Juonniite | CaMgSc(PO4)2(OH) · 4H2O |
| 8.DH.20 | Overite | CaMgAl(PO4)2(OH) · 4H2O |
| 8.DH.25 | Calcioferrite | Ca4MgFe3+4(PO4)6(OH)4 · 12H2O |
| 8.DH.25 | Zodacite | Ca4Mn2+Fe3+4(PO4)6(OH)4 · 12H2O |
| 8.DH.25 | Fanfaniite | Ca4Mn2+Al4(PO4)6(OH)4 · 12H2O |
| 8.DH.25 | Kingsmountite | Ca3Mn2+FeAl4(PO4)6(OH)4 · 12H2O |
| 8.DH.25 | Montgomeryite | Ca4MgAl4(PO4)6(OH)4 · 12H2O |
| 8.DH.30 | Pararobertsite | Ca2Mn3+3(PO4)3O2 · 3H2O |
| 8.DH.30 | Robertsite | Ca2Mn3+3(PO4)3O2 · 3H2O |
| 8.DH.30 | Arseniosiderite | Ca2Fe3+3(AsO4)3O2 · 3H2O |
| 8.DH.30 | Sailaufite | (Ca,Na,◻)2Mn3+3(AsO4)2(CO3)O2 · 3H2O |
| 8.DH.30 | Mitridatite | Ca2Fe3+3(PO4)3O2 · 3H2O |
| 8.DH.30 | Kolfanite | Ca2Fe3+3O2(AsO4)3 · 2H2O |
| 8.DH.35 | Mantienneite | KMg2Al2Ti(PO4)4(OH)3 · 15H2O |
| 8.DH.35 | Sperlingite | (H2O)K(Mn2+Fe3+)(Al2Ti)(PO4)4[O(OH)] [(H2O)9(OH)] · 4H2O |
| 8.DH.35 | Paulkerrite | K(Mg,Mn2+)2(Fe3+,Al,Ti,Mg)2Ti(PO4)4(OH)3 · 15H2O |
| 8.DH.35 | Hydroxylbenyacarite | (H2O)2Mn2(Ti2Fe)(PO4)4[O(OH)](H2O)10 · 4H2O |
| 8.DH.35 | Macraeite | K(H2O)Mn2(Fe2Ti)(PO4)4[O(OH)](H2O)10 · 4H2O |
| 8.DH.35 | Benyacarite | (H2O)2Mn2Ti2Fe3+(PO4)4(OF)(H2O)10 · 4H2O |
| 8.DH.35 | Fluormacraeite | [(H2O)K]Mn2(Fe2Ti)(PO4)4(OF)(H2O)10 · 4H2O |
| 8.DH.40 | Xanthoxenite | Ca4Fe3+2(PO4)4(OH)2 · 3H2O |
| 8.DH.45 | Mahnertite | NaCu3(AsO4)2Cl · 5H2O |
| 8.DH.50 | Andyrobertsite | KCdCu5(AsO4)4(H2AsO4) · 2H2O |
| 8.DH.50 | Calcioandyrobertsite | KCaCu5(AsO4)4(H2AsO4) · 2H2O |
| 8.DH.55 | Englishite | K3Na2Ca10Al15(PO4)21(OH)7 · 26H2O |
| 8.DH.60 | Bouazzerite | Bi6(Mg,Co)11Fe3+14(AsO4)18(OH)4O12 · 86H2O |
| 8.DH.65 | Galliskiite | Ca4Al2(PO4)2F8 · 5H2O |
| 8.DH.70 | Joteite | Ca2CuAl(AsO4)[AsO3(OH)]2(OH)2 · 5H2O |
| 8.DH.75 | Kampelite | Ba6Mg3Sc8(PO4)12(OH)6 · 7H2O |
| 8.DH.80 | Kapundaite | NaCaFe4(PO4)4(OH)3 · 5H2O |
| 8.DH.85 | Vaniniite | Ca2Mn2+3Mn3+2O2(AsO4)4 · 2H2O |
Fluorescence of Keckite
Not fluorescent
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 Keckite
mindat.org URL:
https://www.mindat.org/min-2174.html
Please feel free to link to this page.
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References for Keckite
Reference List:
Fleischer, Michael, Burns, Roger G., Cabri, Louis J., Chao, George Y., Hogarth, D. D., Pabst, Adolf (1979) New Mineral Names. American Mineralogist, 64 (11-12) 1329-1334
Localities for Keckite
Showing 11 localities.
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.
Australia | |
| Dr. Bill Birch - Museum Victoria |
DR Congo | |
| Mills et al. (2010) |
Germany | |
| Weiß (1990) +1 other reference |
| Dill et al. (2008) |
| Dill (2009) |
| Neues Jahrb.Min. (1979) +2 other references | |
| Kastning et al. (1996) +2 other references |
Portugal | |
| |
| Schnorrer-Köhler et al. (1991) |
Spain | |
| www.foro-minerales.com (n.d.) |
USA | |
| Whitmore et al. (2004) +2 other references |
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The
Hagendorf South Pegmatite, Hagendorf, Waidhaus, Neustadt an der Waldnaab District, Upper Palatinate, Bavaria, Germany