Matlockite

Matlockite
General
CategoryHalide minerals
Formula
(repeating unit)
PbFCl
IMA symbolMtl[1]
Strunz classification3.DC.25
Dana classification9.2.11.1
Crystal systemTetragonal
Crystal classDitetragonal dipyramidal (4/mmm)
H-M symbol: (4/m 2/m 2/m)
Space groupP4/nmm
Unit cella = 4.11 Å, c = 7.23 Å; Z = 2
Identification
ColourColourless to yellow and greenish
Crystal habitFlattened, tabular crystals occurring as aggregates, rosettelike, radiating, hemispherical; also massive
Cleavage{001}, perfect
FractureUneven to subconchoidal
TenacityBrittle
Mohs scale hardness2.5 – 3
LusterAdamantine, pearly on {001}
DiaphaneityTransparent
Specific gravity7.1 – 7.2
Optical propertiesUniaxial (−)
Refractive indexnω = 2.150 nε = 2.040
References[2][3][4]

Matlockite is a rare lead halide mineral, named after the town of Matlock in Derbyshire, England, where it was first discovered in a nearby mine.[3] Matlockite (chemical formula: PbFCl) gives its name to the matlockite group which consists of rare minerals of a similar structure.

  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. ^ a b Handbook of Mineralogy
  4. ^ Mindat.org