Liskeardite
A valid IMA mineral species - grandfathered
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About Liskeardite
Formula:
[(Al,Fe)32(AsO4)18(OH)42(H2O)22] · 52H2O
Formerly thought to be (Al,Fe3+)3(AsO4)(OH)6.5H2O.
Colour:
White, greenish, bluish, brownish; colourless in transmitted light.
Crystal System:
Monoclinic
Name:
Named after the community of Liskeard, Cornwall, England, UK, near the type locality.
A secondary mineral resulting from the oxidation of arsenic-bearing sulfides.
Chemically similar to bettertonite.
Chemically similar to bettertonite.
Unique Identifiers
Mindat ID:
2416
Long-form identifier:
mindat:1:1:2416:3
GUID
(UUID V4):
(UUID V4):
6755c4ad-3d80-4b13-9af6-661b985885d0
IMA Classification of Liskeardite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
(Al,Fe)32(AsO4)18(OH)42(H2O)22 · 52H2O
First published:
1878
Type description reference:
Classification of Liskeardite
8.DF.10
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
F : With only medium-sized cations, (OH,etc.):RO4 > 3:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
F : With only medium-sized cations, (OH,etc.):RO4 > 3:1
42.1.1.1
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
1 : A3(XO4)Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
1 : A3(XO4)Zq·xH2O
20.9.14
20 : Arsenates (also arsenates with phosphate, but without other anions)
9 : Arsenates of Fe
20 : Arsenates (also arsenates with phosphate, but without other anions)
9 : Arsenates of Fe
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 |
---|---|---|
Lsk | 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 Liskeardite
Pronunciation:
Play | Recorded by | Country |
---|---|---|
Jolyon Ralph | United Kingdom |
Physical Properties of Liskeardite
Transparency:
Translucent
Colour:
White, greenish, bluish, brownish; colourless in transmitted light.
Optical Data of Liskeardite
Type:
Biaxial (+)
RI values:
nα = 1.661 nβ = 1.675 nγ = 1.689
2V:
Measured: 90° , Calculated: 88°
Max Birefringence:
δ = 0.028
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:
High
Dispersion:
r < v strong
Chemistry of Liskeardite
Mindat Formula:
[(Al,Fe)32(AsO4)18(OH)42(H2O)22] · 52H2O
Formerly thought to be (Al,Fe3+)3(AsO4)(OH)6.5H2O.
Formerly thought to be (Al,Fe3+)3(AsO4)(OH)6.5H2O.
Crystallography of Liskeardite
Crystal System:
Monoclinic
Cell Parameters:
a = 24.576(5) Å, b = 7.754(2) Å, c = 24.641(5) Å
β = 90.19(1)°
β = 90.19(1)°
Ratio:
a:b:c = 3.169 : 1 : 3.178
Unit Cell V:
4,695.62 ų (Calculated from Unit Cell)
Morphology:
Massive, crusts with a radial-fibrous structure.
Comment:
space group I2, crystal structure was determined using synchrotron data collected on a 2 μm diameter fibre at 100 K.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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CIF File Best | x | y | z | a | b | c
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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) |
---|---|---|---|---|---|---|---|
0020528 | Liskeardite | Grey I E, Mumme W G, Macrae C M, Caradoc-Davies T, Price J R, Rumsey M S, Mills S J (2013) Chiral edge-shared octahedral chains in liskeardite, [(Al,Fe)32(AsO4)18(OH)42(H2O)22] *52H2O, an open framework mineral with a pharmacoalumite-related structure Mineralogical Magazine 77 3125-3135 | 2013 | Marke Valley mine, Liskeard District, Cornwall, UK | 0 | 100 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
17.6 Å | (100) |
12.2 Å | (60) |
8.65 Å | (80) |
7.85 Å | (65) |
7.44 Å | (60) |
5.66 Å | (20) |
4.76 Å | (20) |
4.56 Å | (20) |
4.25 Å | (40) |
3.95 Å | (40) |
3.44 Å | (20) |
3.33 Å | (100) |
3.22 Å | (40) |
3.12 Å | (20) |
2.85 Å | (40) |
2.78 Å | (40) |
2.59 Å | (40) |
2.47 Å | (20) |
2.37 Å | (60) |
2.28 Å | (40) |
2.24 Å | (40) |
Comments:
Data from Guillemin (1952) for specimen from Cap Garonne.
Type material gives a poor X-ray pattern.
Type material gives a poor X-ray pattern.
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 7: Great Oxidation Event | <2.4 |
47a : [Near-surface hydration of prior minerals] | |
47d : [Arsenates, antimonates, selenates, bismuthinates] |
Type Occurrence of Liskeardite
General Appearance of Type Material:
Occurs as a layer, several millimeters thick, with uniform, fibrous structure, coating quartz in pockets.
Place of Conservation of Type Material:
The Natural History Museum, London, England, UK - #50821.
Associated Minerals at Type Locality:
Reference:
Maskelyne, N.S. (1878) A new mineral. Nature: 18: 426-426.
Other Language Names for Liskeardite
German:Liskeardit
Spanish:Liskeardita
Common Associates
Associated Minerals Based on Photo Data:
3 photos of Liskeardite associated with Scorodite | Fe3+AsO4 · 2H2O |
1 photo of Liskeardite associated with Chalcophyllite | Cu18Al2(AsO4)4(SO4)3(OH)24 · 36H2O |
1 photo of Liskeardite associated with Cyanotrichite | Cu4Al2(SO4)(OH)12 · 2H2O |
Related Minerals - Strunz-mindat Grouping
8.DF. | Kernowite | Cu2Fe(AsO4)(OH)4 · 4H2O |
8.DF. | Wiperamingaite | NaCaFe3+Al(PO4)F5(OH) · H2O |
8.DF.05 | Hotsonite | Al11(SO4)3(PO4)2(OH)21 · 16H2O |
8.DF.10 | Bolivarite | Al2(PO4)(OH)3 · 4-5H2O |
8.DF.10 | Evansite | Al3(PO4)(OH)6 · 6H2O |
8.DF.10 | Rosièresite | (Pb, Cu, Al, P, O, H) |
8.DF.15 | Rusakovite | (Fe3+,Al)5(VO4,PO4)2(OH)9 · 3H2O |
8.DF.20 | Liroconite | Cu2Al(AsO4)(OH)4 · 4H2O |
8.DF.25 | Sieleckiite | Cu3Al4(PO4)2(OH)12 · 2H2O |
8.DF.30 | Chalcophyllite | Cu18Al2(AsO4)4(SO4)3(OH)24 · 36H2O |
8.DF.35 | Parnauite | Cu9(AsO4)2(SO4)(OH)10 · 7H2O |
8.DF.40 | Gladiusite | Fe2(Fe,Mg)4(PO4)(OH)11(H2O) |
8.DF.50 | Forêtite | Cu2Al2(AsO4)(OH,O,H2O)6 |
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 Liskeardite
mindat.org URL:
https://www.mindat.org/min-2416.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Liskeardite
Localities for Liskeardite
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.
France | |
| Guillemin (1952) |
Germany | |
| rruff.geo.arizona.edu (n.d.) |
Russia | |
| Bortnikova et al. (2017) |
UK | |
| |
| |
| Bulletin de la Société française de Minéralogie et de Cristallographie (1952) |
| Golley et al. (1995) +1 other reference |
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Marke Valley Mine, Upton Cross, Linkinhorne, Cornwall, England, UK