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Matlockite
A valid IMA mineral species - grandfathered
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About Matlockite
Formula:
PbFCl
Colour:
Colourless, light yellow to light golden-yellow, greenish
Lustre:
Adamantine, Pearly
Hardness:
2½ - 3
Specific Gravity:
7.12
Crystal System:
Tetragonal
Member of:
Name:
After the locality near Matlock, Derbyshire, England.
Unique Identifiers
Mindat ID:
2593
Long-form identifier:
mindat:1:1:2593:1
Similar Names
| Matlockite (of Chapman) | A synonym of Phosgenite |
IMA Classification of Matlockite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Pb2+ClF
First published:
1851
Classification of Matlockite
3.DC.25
3 : HALIDES
D : Oxyhalides, hydroxyhalides and related double halides
C : With Pb (As,Sb,Bi), without Cu
3 : HALIDES
D : Oxyhalides, hydroxyhalides and related double halides
C : With Pb (As,Sb,Bi), without Cu
9.2.11.1
9 : NORMAL HALIDES
2 : AX2
9 : NORMAL HALIDES
2 : AX2
8.8.2
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
8 : Halides of Pb
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
8 : Halides of Pb
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Mtl | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Matlockite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Matlockite
Adamantine, Pearly
Transparency:
Transparent
Colour:
Colourless, light yellow to light golden-yellow, greenish
Hardness:
2½ - 3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
On {001}.
On {001}.
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
7.12 g/cm3 (Measured) 7.16 g/cm3 (Calculated)
Optical Data of Matlockite
Type:
Uniaxial (-)
RI values:
nω = 2.15 nε = 2.04
Max. Birefringence:
δ = 0.110
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Comments:
Biaxial with small 2V at times, the result of subparallel growth or strain.
Chemistry of Matlockite
Mindat Formula:
PbFCl
Element Weights:
Elements listed:
Crystallography of Matlockite
Crystal System:
Tetragonal
Class (H-M):
4/mmm(4/m2/m2/m) - Ditetragonal Dipyramidal
Space Group:
P4/nmm
Cell Parameters:
a = 4.11 Å, c = 7.23 Å
Ratio:
a:c = 1 : 1.759
Unit Cell V:
122.13 ų (Calculated from Unit Cell)
Morphology:
Crystals usually tabular {001}; also as stout pyramidal crystals with smal prism faces. Subparallel aggregates of platy crystals; as hemispherical, rosette-like groups. Massive; coarsely lamellar.
Crystal Structure
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Labels
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0014521 | Matlockite | Pasero M, Perchiazzi N (1996) Crystal structure refinement of matlockite Mineralogical Magazine 60 833-836 |  | 1996 | Baratti beach, Tuscany, Italy | 0 | 293 |
| 0014434 | Matlockite | Bannister F A, Hey M H (1934) The crystal-structure and optical properties of matlockite (PbFCl) Mineralogical Magazine 23 587-597 | 1934 | Matlock, Derbyshire, England | 0 | 293 | |
| 0011855 | Matlockite | Wyckoff R W G (1963) Second edition. Interscience Publishers, New York, New York Crystal Structures 1 294-296 | 1963 | 0 | 293 | ||
| 0017948 | Matlockite | Nieuwenkamp W, Bijvoet J (1932) Die Kristallstruktur von Bleifluochlorid Pb F Cl _cod_database_code 1011046 Zeitschrift fur Kristallographie 81 469-473 | 1932 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.574 Å | (100) |
| 2.906 Å | (45) |
| 3.617 Å | (40) |
| 2.265 Å | (40) |
| 2.715 Å | (35) |
| 1.781 Å | (25) |
| 2.055 Å | (20) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45b : [Other oxidized fumarolic minerals] | |
| 47a : [Near-surface hydration of prior minerals] |
Type Occurrence of Matlockite
Place of Conservation of Type Material:
Natural History Museum, London, England, 89055.
Associated Minerals at Type Locality:
Synonyms of Matlockite
Lead oxychloride (in part)
Other Language Names for Matlockite
Relationship of Matlockite to other Species
Member of:
Other Members of Matlockite Group:
| Bismoclite | BiOCl | Tet. 4/mmm(4/m2/m2/m) : P4/nmm |
| Daubréeite | BiO(OH) | Tet. 4/mmm(4/m2/m2/m) : P4/nmm |
| Laurionite | PbCl(OH) | Orth. mmm(2/m2/m2/m) |
| Paralaurionite | PbCl(OH) | Mon. 2/m : B2/m |
| Rorisite | CaFCl | Tet. 4/mmm(4/m2/m2/m) : P4/nmm |
| Zavaritskite | (BiO)F | Tet. 4/mmm(4/m2/m2/m) : P4/nmm |
Common Associates
Associations Based on Photo Data:
| 13 photos of Matlockite associated with Diaboleite | Pb2CuCl2(OH)4 |
| 8 photos of Matlockite associated with Phosgenite | Pb2CO3Cl2 |
| 6 photos of Matlockite associated with Wherryite | Pb7Cu2(SO4)4(SiO4)2(OH)2 |
| 6 photos of Matlockite associated with Leadhillite | Pb4(CO3)2(SO4)(OH)2 |
| 5 photos of Matlockite associated with Galena | PbS |
| 4 photos of Matlockite associated with Laurionite | PbCl(OH) |
| 4 photos of Matlockite associated with Anglesite | PbSO4 |
| 4 photos of Matlockite associated with Paralaurionite | PbCl(OH) |
| 3 photos of Matlockite associated with Baryte | BaSO4 |
| 2 photos of Matlockite associated with Mattheddleite | Pb5(SiO4)1.5(SO4)1.5(Cl,OH) |
Related Minerals - Strunz-mindat Grouping
| 3.DC. | Gajardoite | KCa0.5As3+4O6Cl2 · 5H2O |
| 3.DC. | Lucabindiite | (K,NH4)As4O6(Cl,Br) |
| 3.DC. | Cuatrocapaite-(NH4) | (NH4)3(NaMg◻)(As2O3)6Cl6 · 16H2O |
| 3.DC. | Cuatrocapaite-(K) | K3(NaMg◻)(As2O3)6Cl6 · 16H2O |
| 3.DC. | Napoliite | Pb2OFCl |
| 3.DC. | Torrecillasite | Na(As,Sb)3+4O6Cl |
| 3.DC.05 | Paralaurionite | PbCl(OH) |
| 3.DC.05 | Laurionite | PbCl(OH) |
| 3.DC.05 | Mauriziodiniite | (NH4)(As2O3)2I |
| 3.DC.05 | Russoite | (NH4)ClAs2O3(H2O)0.5 |
| 3.DC.10 | Fiedlerite | Pb3FCl4(OH) · H2O |
| 3.DC.15 | Penfieldite | Pb2Cl3(OH) |
| 3.DC.15 | Telluroperite | Pb3TeO4Cl2 |
| 3.DC.20 | Laurelite | Pb7F12Cl2 |
| 3.DC.25 | Zhangpeishanite | BaFCl |
| 3.DC.25 | Zavaritskite | (BiO)F |
| 3.DC.25 | Rorisite | CaFCl |
| 3.DC.25 | Bismoclite | BiOCl |
| 3.DC.25 | Vegrandisite | BaCl2 |
| 3.DC.30 | Nadorite | PbSbClO2 |
| 3.DC.30 | Perite | PbBiClO2 |
| 3.DC.40 | Thorikosite | Pb3Cl2(OH)(SbO3,AsO3) |
| 3.DC.45 | Mereheadite | Pb47Cl25(OH)13O24(CO3)(BO3)2 |
| 3.DC.50 | Blixite | Pb8O5(OH)2Cl4 |
| 3.DC.52 | Rumseyite | Pb2OClF |
| 3.DC.55 | Vladkrivovichevite | [Pb32O18][Pb4Mn2O]Cl14(BO3)8 · 2H2O |
| 3.DC.55 | Pinalite | Pb3WO5Cl2 |
| 3.DC.57 | Yeomanite | Pb2O(OH)Cl |
| 3.DC.60 | Symesite | Pb10(SO4)O7Cl4 · H2O |
| 3.DC.60 |
Passa Limani Cove slag locality, Lavreotiki Municipal Unit, Lavreotiki, East Attica, Attica, Greece