Chemistry:Liroconite
Liroconite | |
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General | |
Category | Arsenate minerals |
Formula (repeating unit) | Cu2Al[(OH)4|AsO4]·4(H2O) |
Strunz classification | 8.DF.20 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | I2/a |
Unit cell | a = 12.66, b = 7.57 c = 9.89 [Å]; β = 91.25°; Z = 4 |
Identification | |
Color | Bright blue to green |
Crystal habit | Typically as striated flattened octahedral or lenticular crystals, also massive to granular |
Cleavage | Indistinct on {110} and {011} |
Fracture | Irregular/uneven, conchoidal |
Mohs scale hardness | 2–2 1⁄2 |
|re|er}} | Vitreous to resinous |
Streak | Light blue |
Diaphaneity | Transparent, translucent |
Specific gravity | 2.9–3 |
Optical properties | Biaxial (−) |
Refractive index | nα = 1.612 nβ = 1.652 nγ = 1.675 |
Birefringence | δ = 0.063 |
2V angle | Measured: 67° |
References | [1][2][3] |
Liroconite is a complex mineral: Hydrated copper aluminium arsenate hydroxide, with the formula Cu2Al[(OH)4|AsO4]·4(H2O). It is a vitreous monoclinic mineral, colored bright blue to green, often associated with malachite, azurite, olivenite, and clinoclase. It is quite soft, with a Mohs hardness of 2–2.5, and has a specific gravity of 2.9–3.0.
![](/wiki/images/thumb/c/cb/Liroconite-Clinoclase-120699.jpg/250px-Liroconite-Clinoclase-120699.jpg)
It was first identified in 1825 in the tin and copper mines of Devon and Cornwall, England. Although it remains quite rare it has subsequently been identified in a variety of locations including France , Germany , Australia , New Jersey and California .[1]
The type locality for liroconite is Wheal Gorland in St Day, Cornwall in the United Kingdom.[1] The largest crystal specimen on public display is in the Royal Cornwall Museum in Truro.[5]
It occurs as a secondary mineral in copper deposits in association with olivenite, chalcophyllite, clinoclase, cornwallite, strashimirite, malachite, cuprite and limonite.[3]
Structure
Liroconite crystallizes in the monoclinic crystal system.[3]:1[6] The crystal structure consists of a framework of AsO4 tetrahedra, Jahn-Teller-distorted [CuO2(OH)2(H2O)2] octahedra and [AlO2(OH)4] octahedra.[7]
See also
- Kernowite – an isostructural mineral with iron in place of aluminium
References
- ↑ 1.0 1.1 1.2 Mindat.org: Liroconite mineral information and data
- ↑ Webmineral data
- ↑ 3.0 3.1 3.2 Handbook of Mineralogy
- ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode: 2021MinM...85..291W.
- ↑ Aubrey-Jones, David (2008). "Liroconite". http://britishrocks.com/.
- ↑ Kolesova, R.V.; Fesenko, E.G. (Dec 1968). "Determination of the crystal structure of Liroconite Cu2Al[AsO4(OH)4 [math]\displaystyle{ \cdot }[/math] 4 H2O"]. Soviet Physics – Crystallography (Rostov University) 13 (3): 396–402. https://rruff-2.geo.arizona.edu/uploads/SPC13_324.pdf.
- ↑ Burns, Peter C.; Eby, Ray K.; Hawthorne, Frank C. (1991). "Refinement of the structure of liroconite, a heteropolyhedral framework oxysalt mineral". Acta Crystallogr. C 47 (5): 916–919. doi:10.1107/S0108270190010939.
![]() | Original source: https://en.wikipedia.org/wiki/Liroconite.
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