Paralaurionite | |
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Platey clear paralaurionite crystals from slag in the Thorikos area, Lavrion, Attica, Greece | |
General | |
Category | Halide mineral |
Formula (repeating unit) | PbCl(OH) |
IMA symbol | Plri |
Strunz classification | 3.DC.05 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | C2/m |
Unit cell | a = 10.865(4) Å, b = 4.006(2) Å, c = 7.233(3) Å; β = 117.24(4)°; Z = 4 |
Identification | |
Color | Colorless, white, pale greenish, yellowish, yellow-orange, rarely violet |
Crystal habit | Elongated tabular crystals |
Twinning | Contact twinning on {100} |
Cleavage | Perfect on {001} |
Tenacity | Flexible, non-elastic |
Mohs scale hardness | 3 |
Luster | Subadamantine |
Diaphaneity | Transparent to translucent |
Specific gravity | 6.05–6.15 |
Optical properties | Biaxial (−) |
Refractive index | nα = 2.050 nβ = 2.150 nγ = 2.200 |
Birefringence | δ = 0.150 |
Pleochroism | Visible |
References |
Paralaurionite is a colorless mineral consisting of a basic lead chloride PbCl(OH) that is dimorphous with laurionite. It is a member of the matlockite group. The name is derived from para-, the Greek for "near", and laurionite, because of its polymorphic relationship to it. Bright, yellow tips of thorikosite can form on paralaurionite crystals and paralaurionite may also be intergrown with mendipite.
Occurrence
It was first described in 1899 for an occurrence in slag in Laurium, Attica, Greece. In 1952 an occurrences of it was reported from the Mammoth Mine, Arizona.
It occurs in lead bearing slag which has been exposed to seawater. It also occurs in polymetallic ore deposits. It occurs associated with laurionite, penfieldite, fiedlerite, phosgenite in slag deposits; and with leadhillite, matlockite, cerussite, hydrocerussite, diaboleite and wherryite in the Mammoth mine location.
References
- Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- Mineralienatlas
- ^ Handbook of Mineralogy
- ^ Paralaurionite on Mindat.org
- Paralaurionite on Webmineral
- Mineralogical magazine. Mineralogical Society, HighWire Press. 1 January 2006. pp. 643–8. Retrieved 26 January 2012.
- The Mineralogical record. 1986. pp. 185–88. Retrieved 26 January 2012.
- Williams, Peter A. (August 1990). Oxide zone geochemistry. E. Horwood. pp. 262–4. ISBN 978-0-13-647553-8. Retrieved 26 January 2012.
- Mineralogical Society (Great Britain) (1952). The Mineralogical magazine and journal of the Mineralogical Society. Mineralogical Society. pp. 341–2. Retrieved 26 January 2012.
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