Franckeite
A valid IMA mineral species - grandfathered
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About Franckeite
Formula:
Fe2+(Pb,Sn2+)6Sn4+2Sb2S14
Colour:
Grey-black, black; iridescent at times
Lustre:
Metallic
Hardness:
2½ - 3
Specific Gravity:
5.90
Crystal System:
Triclinic
Member of:
Name:
Named in honor of brothers Johann Heinrich Karl (Carl) Francke (1832–1907) and Ernst Otto Francke (16 April 1838, Kassel, Germany - 18 May 1913, Kissingen, Germany), mining engineers, for the promotion of the mineralogy, geology and paleontology of the Bolivian highlands. They supplied the first specimens for study.
Unique Identifiers
Mindat ID:
1592
Long-form identifier:
mindat:1:1:1592:5
IMA Classification of Franckeite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Pb2+21.7Sn4+9.3(Fe2+,Fe3+)4.0Sb3+8.1S2-56.9
First published:
1893
Classification of Franckeite
2.HF.25b
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
H : Sulfosalts of SnS archetype
F : With SnS and PbS archetype structure units
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
H : Sulfosalts of SnS archetype
F : With SnS and PbS archetype structure units
3.1.4.2
3 : SULFOSALTS
1 : ø > 4
3 : SULFOSALTS
1 : ø > 4
6.1.18
6 : Sulphosalts - Sulphostannates, Sulphogermanates,Sulpharsenates, Sulphantimonates, Sulphovanadates and Sulphohalides
1 : Sulphostannates and other sulfides containing Sn
6 : Sulphosalts - Sulphostannates, Sulphogermanates,Sulpharsenates, Sulphantimonates, Sulphovanadates and Sulphohalides
1 : Sulphostannates and other sulfides containing Sn
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Fke | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Fr | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Franckeite
Metallic
Transparency:
Opaque
Colour:
Grey-black, black; iridescent at times
Streak:
Grayish black
Hardness:
2½ - 3 on Mohs scale
Tenacity:
Malleable
Cleavage:
Perfect
{010} perfect.
{010} perfect.
Comment:
Flexible, inelastic
Density:
5.90(2) g/cm3 (Measured) 5.88 g/cm3 (Calculated)
Optical Data of Franckeite
Anisotropism:
Weak
Reflectivity:
| Wavelength | R1 (%) |
|---|---|
| 400nm | 38.2-39.4% |
| 420nm | 37.9-39.2% |
| 440nm | 37.6-39.0% |
| 460nm | 37.3-38.7% |
| 480nm | 36.9-38.5% |
| 500nm | 36.6-38.2% |
| 520nm | 36.2-37.9% |
| 540nm | 35.8-37.6% |
| 560nm | 35.4-37.3% |
| 580nm | 35.0-36.9% |
| 600nm | 34.6-36.5% |
| 620nm | 34.2-36.1% |
| 640nm | 33.8-35.7% |
| 660nm | 33.4-35.3% |
| 680nm | 33.0-34.9% |
| 700nm | 32.6-34.5% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 38.2-39.4%.
Colour in reflected light:
Gray-white
Pleochroism:
Weak
Comments:
Very weak.
Chemistry of Franckeite
Mindat Formula:
Fe2+(Pb,Sn2+)6Sn4+2Sb2S14
Element Weights:
Common Impurities:
Zn,Ag,Ge,In
Crystallography of Franckeite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 46.9 Å, b = 5.82 Å, c = 17.3 Å
α = 90°, β = 94.66°, γ = 90°
α = 90°, β = 94.66°, γ = 90°
Ratio:
a:b:c = 8.058 : 1 : 2.973
Unit Cell V:
4,706.56 ų (Calculated from Unit Cell)
Z:
8
Morphology:
Thin tabular {010}, elongated [100]; {010} striated [001], and less markedly [100]. Usually massive, radial, or foliated; often in spherical, rosette-like or cauliform aggregates of thin plates. Crystals often warped or bent.
Twinning:
Complex.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0018603 | Franckeite | Makovicky E, Petricek V, Dusek M, Topa D (2011) The crystal structure of franckeite, Pb21.7Sn9.3Fe4.0Sb8.1S56.9 American Mineralogist 96 1686-1702 | 2011 | San Jose, Bolivia | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.44 Å | (100) |
| 2.91 Å | (100) |
| 2.86 Å | (100) |
| 2.82 Å | (100) |
| 2.05 Å | (75) |
| 4.30 Å | (50) |
| 3.11 Å | (50) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Geological Setting:
Limestone contact metamorphic rocks
Type Occurrence of Franckeite
Geological Setting of Type Material:
Hydrothermal Ag-Sn deposits
Synonyms of Franckeite
Other Language Names for Franckeite
Varieties of Franckeite
| Incaite | A Sn(II)-rich variety of franckeite. See also potosíite. Originally described from Santa Cruz Mine, Poopó town, Poopó Province, Oruro Department, Bolivia. |
| Potosíite | A Sn(II)-poor variety of franckeite originally thought to be a separate species. See also incaite. Originally reported from Andacaba deposit, Linares Province, Potosí Department, Bolivia. |
Relationship of Franckeite to other Species
Member of:
Other Members of Franckeite Group:
Common Associates
Associations Based on Photo Data:
| 262 photos of Franckeite associated with 'Potosíite' | Pb6Sn3FeSb3S16 |
| 88 photos of Franckeite associated with Pyrite | FeS2 |
| 58 photos of Franckeite associated with Sphalerite | ZnS |
| 45 photos of Franckeite associated with Quartz | SiO2 |
| 31 photos of Franckeite associated with Zinkenite | Pb9Sb22S42 |
| 27 photos of Franckeite associated with Jamesonite | Pb4FeSb6S14 |
| 27 photos of Franckeite associated with Galena | PbS |
| 23 photos of Franckeite associated with Cylindrite | Pb3Sn4FeSb2S14 |
| 20 photos of Franckeite associated with Vauxite | Fe2+Al2(PO4)2(OH)2 · 6H2O |
| 18 photos of Franckeite associated with Boulangerite | Pb5Sb4S11 |
Related Minerals - Strunz-mindat Grouping
| 2.HF. | Ramosite | Pb25.7Sn8.3Mn3.4Sb6.4S56.2 |
| 2.HF.20 | Vrbaite | Hg3Tl4As8Sb2S20 |
| 2.HF.25a | Merelaniite | Mo4Pb4VSbS15 |
| 2.HF.25a | Abramovite | Pb2SnInBiS7 |
| 2.HF.25a | Lévyclaudite | Pb8Sn7Cu3(Bi,Sb)3S28 |
| 2.HF.25a | Cylindrite | Pb3Sn4FeSb2S14 |
| 2.HF.25b | 'Potosíite' | Pb6Sn3FeSb3S16 |
| 2.HF.25b | Coiraite | (Pb,Sn)12.5Sn5FeAs3S28 |
| 2.HF.25b v | 'Plumbostannite' | Pb2Fe2Sn2Sb2S11 |
| 2.HF.30 | Lengenbachite | Ag4Cu2Pb18As12S39 |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Franckeite
mindat.org URL:
https://www.mindat.org/min-1592.html
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References for Franckeite
Reference List:
Prior, G. T. (1904) On Teallite, a new sulphostannite of lead from Bolivia ; and its relations to Franckeite and Cylindrite. Mineralogical Magazine and Journal of the Mineralogical Society, 14 (63) 21-27 doi:10.1180/minmag.1904.014.63.06
Coulon, M., Heitz, F., Le Bihan, Marie-Thérèse (1961) Contribution à l'étude structurale d'un sulfure de plomb, d'antimoine et d'étain : la Frankeite. Bulletin de Minéralogie, 84 (4) 350-353 doi:10.3406/bulmi.1961.5513
Williams, T. B., Hyde, B. G. (1988) Electron microscopy of cylindrite and franckeite. Physics and Chemistry of Minerals, 15 (6) 521-544 doi:10.1007/bf00311023
Wang, S., Kuo, K. H. (1991) Crystal lattices and crystal chemistry of cylindrite and franckeite. Acta Crystallographica Section A Foundations of Crystallography, 47 (4). 381-392 doi:10.1107/s0108767390009242
Makovicky, Emil, Petříček, Václav, Dušek, Michal, Topa, Dan (2009) The misfit layer structure of franckeite. Acta Crystallographica Section A Foundations of Crystallography, 65. doi:10.1107/s0108767309096299
Makovicky, Emil; Petříček, Václav; Dušek, Michal; Topa, Dan (2010) 2D noncommensurate modulated misfit layer structures of franckeite and cylindrite. Acta Crystallographica Section A Foundations of Crystallography, 66 (a1). s62 doi:10.1107/s0108767310098673
Localities for Franckeite
Showing 81 localities.
Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
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The
San José Mine, Oruro, Cercado Province, Oruro, Bolivia