Fettelite
A valid IMA mineral species
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About Fettelite
Formula:
[Ag6As2S7][Ag10HgAs2S8]
Colour:
Dark violet to scarlet
Lustre:
Adamantine, Sub-Metallic
Hardness:
3½
Specific Gravity:
6.29 (Calculated)
Crystal System:
Monoclinic
Name:
Named in honor of Michael Fettel, a collector who contributed to the geology of the Odenwald, and who first collected the mineral.
The Hg analogue of ferrofettelite.
Easy to confuse with polybasite.
Structurally related to the members of the Pearceite Group.
Easy to confuse with polybasite.
Structurally related to the members of the Pearceite Group.
Unique Identifiers
Mindat ID:
1543
Long-form identifier:
mindat:1:1:1543:7
GUID
(UUID V4):
(UUID V4):
d3ee009c-c8b9-453e-88bf-569d428af39e
IMA Classification of Fettelite
Approved
IMA Formula:
[Ag6As2S7][Ag10HgAs2S8]
Approval year:
1994
Classification of Fettelite
2.LA.30
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
L : Unclassified Sulfosalts
A : Without essential Pb
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
L : Unclassified Sulfosalts
A : Without essential Pb
3.2.10.
3 : SULFOSALTS
2 : ø = 4
3 : SULFOSALTS
2 : ø = 4
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 |
|---|---|---|
| Ftt | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Fettelite
Adamantine, Sub-Metallic
Transparency:
Opaque
Colour:
Dark violet to scarlet
Streak:
Vermillion
Hardness:
3½ on Mohs scale
Hardness:
VHN20=138 - 174 kg/mm2 - Vickers
Tenacity:
Brittle
Cleavage:
Perfect
{001}
{001}
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
6.29 g/cm3 (Calculated)
Optical Data of Fettelite
Anisotropism:
Weak
Bireflectance:
From white to brownish grey
Reflectivity:
| Wavelength | R1 | R2 | imR1 | imR2 |
|---|---|---|---|---|
| 470nm | 30.3% | 31.0% | 13.8% | 14.2% |
| 546nm | 27.6% | 29.2% | 12.0% | 13.1% |
| 589nm | 26.0% | 27.6% | 10.8% | 11.7% |
| 650nm | 23.9% | 24.8% | 9.6% | 10.3% |
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 31.0%.
R1 shown in black, R2 shown in red, imR1 shown in green, imR2 shown in blue
Colour in reflected light:
Greyish white
Internal Reflections:
Red
Chemistry of Fettelite
Mindat Formula:
[Ag6As2S7][Ag10HgAs2S8]
Elements listed:
Crystallography of Fettelite
Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Space Group:
B2
Setting:
C2
Cell Parameters:
a = 26.0388(10) Å, b = 15.0651(8) Å, c = 15.5361(8) Å
β = 90.48(1)°
β = 90.48(1)°
Ratio:
a:b:c = 1.728 : 1 : 1.031
Unit Cell V:
6094.2 ų
Z:
8
Morphology:
Platy.
Twinning:
Intimately twinned with six twin domains.
Comment:
Strong hexagonal pseudosymmetry (a = 15.00, c = 15.46 A).
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0004906 | Fettelite | Bindi L, Keutsch F N, Francis C A, Menchetti S (2009) Fettelite, [Ag6As2S7][Ag10HgAs2S8] from Chanarcillo, Chile: Crystal structure, pseudosymmetry, twinning, and revised chemical formula American Mineralogist 94 609-615 |  | 2009 | Chanarcillo, Chile | 0 | 293 |
| 0018386 | Fettelite | Bindi L, Menchetti S (2011) Fast ion conduction character and ionic phase-transition in silver sulfosalts: The case of fettelite [Ag6As2S7][Ag10HgAs2S8] American Mineralogist 96 792-796 | 2011 | Synthetic | 0 | 400 | |
| 0018797 | Fettelite | Bindi L, Downs R T, Spry P G, Pinch W W, Menchetti S (2012) A chemical and structural re-examination of fettelite samples from the type locality, Odenwald, southwest Germany Mineralogical Magazine 76 551-566 | 2012 | Odenwald, southwest Germany | 0 | 293 | |
| 0018798 | Fettelite | Bindi L, Downs R T, Spry P G, Pinch W W, Menchetti S (2012) A chemical and structural re-examination of fettelite samples from the type locality, Odenwald, southwest Germany Mineralogical Magazine 76 551-566 | 2012 | Odenwald, southwest Germany | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.175 Å | (60) |
| 3.091 Å | (100) |
| 2.998 Å | (40) |
| 2.755 Å | (30) |
| 1.878 Å | (80) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-𝑇 alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Type Occurrence of Fettelite
General Appearance of Type Material:
Clusters consisting of hexagonal flakes up to 10 x 200 μm, and as compact, subparallel aggregates of hexagonal tablets up to 50 μm thick.
Place of Conservation of Type Material:
Institute of Mineralogy, University of Heidelberg, Germany.
Associated Minerals at Type Locality:
Reference:
Wang, N., Paniagua, A. (1996) Fettelite, a new Hg-sulfosalt mineral from Odenwald. Neues Jahrbuch für Mineralogie, Monatshefte (1996): 313-320.
Synonyms of Fettelite
Other Language Names for Fettelite
Relationship of Fettelite to other Species
Structurally related to group(s):
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 2.LA. | Gladkovskyite | MnTlAs3S6 |
| 2.LA. | Biagioniite | Tl2SbS2 |
| 2.LA. | Thunderbayite | TlAg3Au3Sb7S6 |
| 2.LA. | Auerbakhite | MnTl2As2S5 |
| 2.LA. | Ferrofettelite | [Ag6As2S7][Ag10FeAs2S8] |
| 2.LA.10 | Dervillite | Ag2AsS2 |
| 2.LA.15 | Daomanite | CuPtAsS2 |
| 2.LA.20 | Vaughanite | TlHgSb4S7 |
| 2.LA.25 | Criddleite | TlAg2Au3Sb10S10 |
| 2.LA.35 | Chaméanite | (Cu,Fe)4As(Se,S)4 |
| 2.LA.40 | Arcubisite | Ag6CuBiS4 |
| 2.LA.45 | Mgriite | Cu3AsSe3 |
| 2.LA.50 | Benleonardite | [Ag6(Sb,As)2S6Te][Ag9Cu(S,Te)2Te2] |
| 2.LA.55 | Tsnigriite | Ag9SbTe3S3 |
| 2.LA.60 | Borovskite | Pd3SbTe4 |
| 2.LA.65 | Jonassonite | AuBi5S4 |
| 2.LA.65 | Nuwaite | Ni6GeS2 |
| 2.LA.65 | Butianite | Ni6SnS2 |
| 2.LA.70 | Raberite | Tl5Ag4As6SbS15 |
| 2.LA.75 | Spaltiite | Tl2Cu2As2S5 |
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 Fettelite
mindat.org URL:
https://www.mindat.org/min-1543.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
References for Fettelite
Reference List:
Localities for Fettelite
symbol to view information about a locality.
The 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.
Chile | |
| Maurizio Dini collection |
| Bindi et al. (2009) | |
| Harvard University specimen | |
| A. Moesta +3 other references | |
Germany (TL) | |
| Neues Jahrbuch Min. Monatschefte 1996 |
| LAPIS 12/1996 +1 other reference |
Italy | |
| Biagioni et al. (2014) |
Morocco | |
| Conclusive SEM-EDS analysis Vincent ... +1 other reference |
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Glasberg quarry, Nieder-Beerbach, Mühltal, Darmstadt-Dieburg, Darmstadt, Hesse, Germany