Where it forms, where it's found
- Type locality
- Marke Valley Mine
- Upton Cross
- Linkinhorne
- Cornwall
- England
- UK
50.5197°, -4.4308°
8recorded occurrences
Safety & handling
Physical
- Transparency
- Translucent
- Colour
- White · greenish · bluish · brownish · colourless in transmitted light.
Optical
- Optical type
- Biaxial (+) · 2V measured = 90° · 2V calc = 88°
- Refractive index
- 1.661 – 1.689
- Surface relief
- High
- Principal indices
- nα 1.661 · nβ 1.675 · nγ 1.689
- Dispersion
- r < v strong
Δ = 0Δmax
PPLpleochroism per grain
XPLindependent extinctions · rotate the stage
PPLpleochroism only · colour blends on rotation
XPLinterference colour · extinct every 90°
Retardation280 nm
Order1st order
XPL colour
Crystallography
- Cell parameters
- a = 24.576(5) Å · b = 7.754(2) Å · c = 24.641(5) Å
- Cell angles
- β = 90.19(1) °
- Ratio a:b:c
- 1 : 0.316 : 1.003
- Morphology
Massive, crusts with a radial-fibrous structure.
- Type-locality form
Occurs as a layer, several millimeters thick, with uniform, fibrous structure, coating quartz in pockets.
- Comment
space group I2, crystal structure was determined using synchrotron data collected on a 2 μm diameter fibre at 100 K.
Crystal structure
Chemical composition
Synonyms
- Liskeardiet
In other languages
- German
- Liskeardit
- Italian
- liskeardite
Classification
Strunz
10th ed.8.DF.10
- 8Phosphates, Arsenates, VanadatesClass
- 8.DPhosphates, etc. with additional anions, with H2ODivision
- 8.DFWith only medium-sized cations, (OH,etc.):RO4 > 3:1Group
- 8.DF.10LiskearditeSpecies
Dana
8th ed.42.01.01.01
- 42Hydrated Phosphates, Etc.containing Hydroxyl or HalogenClass
- 42.01A3(XO4)Zq·xH2OType
- 42.01.01— unnamed intermediate level —Group
- 42.01.01.01LiskearditeSpecies
CIM
—20.9.14
- 20Arsenates (also arsenates with phosphate, but without other anions)Class
- 20.9Arsenates of FeGroup
- 20.9.14LiskearditeSpecies
Literature, links & citation
Citations
- 1874Talling, R. (1874).
- 1878Maskelyne, N.S. (1878) A new mineral. Nature: 18: 426-426.
- 1883Flight, W. (1883) Two new aluminous mineral species, Evigtokite and Liskeardite. Journal of the Chemical Society, Transactions: 43: 140-142.
- 1901Lacroix, A. (1901) Bulletin de la Société française de Minéralogie: 24: 27.
- 1910Lacroix, A. (1910) Minéralogie de la France et de ses colonies Vol. 4. Library Polytechnique, Paris.
Cite this entry
@misc{mineral2026,
author = {Mineral Index editorial board},
title = {Liskeardite — Mineral Index},
year = {2026},
url = {https://mineralindex.org/minerals/liskeardite-2416},
note = {Accessed 2026-05-11}
}