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Mereheadite

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Mereheadite
General
CategoryHalide
Formula
(repeating unit)
Pb47Cl25(OH)13O24(CO3)(BO3)2
IMA symbolMrh[1]
Strunz classification3.DC.45
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/c
Unit cella = 17.372(1) Å,
b = 27.9419(19) Å,
c = 10.6661(6) Å;
β = 93.152(5)°; Z = 2
Identification
ColorPale yellow
Mohs scale hardness3+12
LusterVitreous, resinous
StreakWhite
Optical propertiesBiaxial
Refractive indexnα = 2.190 nγ = 2.280
Birefringenceδ = 0.090
References[2][3][4][5]

Mereheadite is a rare oxychloride that can be found with Mendipite at Merehead quarry, Cranmore, Somerset, in the United Kingdom. Most specimens are associated with calcite, mendipite or hydrous cerussite in the Manganese pods on vein two at torr works quarry (merehead quarry). This mineral is associated with symesite which is also light yellow to orange. Symesite is found in small blotches on the calcites or mendipites; Mereheadite does not, as it is most often found in veins.

References

[edit]
  1. ^ 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.
  2. ^ Mineralienatlas
  3. ^ Mindat.org
  4. ^ Webmineral.com
  5. ^ Handbook of Mineralogy