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Cafeosite
A valid IMA mineral species
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Formula:
Ca4Fe2+3Fe3+2◻O6S4
(□1−xFex) denotes structural vacancy partially occupied by semimetallic-type Fe (x = 0.2–0.3)
Crystal System:
Orthorhombic
Name:
named сafeosite after its chemical composition
Type Locality:
Known synthetic analogue
A natural iron-bearing oxysulfide, named сafeosite after its chemical composition, is a unique example of a mineral that simultaneously contains iron in three oxidation states: Fe3+, Fe2+, and intermediate between Fe2+ and Fe0 involved in metallic-type FeFe bonding.
A natural iron-bearing oxysulfide, named сafeosite after its chemical composition, is a unique example of a mineral that simultaneously contains iron in three oxidation states: Fe3+, Fe2+, and intermediate between Fe2+ and Fe0 involved in metallic-type FeFe bonding.
Unique Identifiers
Mindat ID:
470994
Long-form identifier:
mindat:1:1:470994:3
IMA Classification of Cafeosite
Approved
IMA Formula:
Ca4Fe2+3Fe3+2 ◻O6S2-4
Approval year:
2024
Classification of Cafeosite
2.MA.15
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
M : Oxysulfosalts
A : Oxysulfosalts of Alkalies and Alkali Earths
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
M : Oxysulfosalts
A : Oxysulfosalts of Alkalies and Alkali Earths
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 |
|---|---|---|
| Cfo | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Optical Data of Cafeosite
Anisotropism:
moderate
Bireflectance:
gray hues
Colour in reflected light:
gray
Internal Reflections:
none
Chemistry of Cafeosite
Mindat Formula:
Ca4Fe2+3Fe3+2◻O6S4
(□1−xFex) denotes structural vacancy partially occupied by semimetallic-type Fe (x = 0.2–0.3)
(□1−xFex) denotes structural vacancy partially occupied by semimetallic-type Fe (x = 0.2–0.3)
Element Weights:
Elements listed:
Crystallography of Cafeosite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pcca
Setting:
Pcca
Cell Parameters:
a = 17.4856(9) Å, b = 11.1516(5) Å, c = 11.1543(5) Å
Ratio:
a:b:c = 1.568 : 1 : 1
Unit Cell V:
2,175.00 ų (Calculated from Unit Cell)
Z:
8
Comment:
Cmce space group. Owing to the small grain size, the crystal structure of the mineral has been studied using synthetic analog, which was found to be isostructural with natural cafeosite based on electron backscatter diffraction (EBSD) data.
Type Occurrence of Cafeosite
General Appearance of Type Material:
tiny anhedral grains that coalesce into irregular aggregates up to 20 μm, commonly encrusted by micrometer-thick troilite or pyrrhotite rims
Place of Conservation of Type Material:
In the collections of the Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Kosygin St. 19, Moscow 119991, Russia, catalogue number 16185
Geological Setting of Type Material:
metamorphosed carbonaceous chondrite
Associated Minerals at Type Locality:
Synonyms of Cafeosite
Other Language Names for Cafeosite
Related Minerals - Strunz-mindat Grouping
| 2.MA.05 | Ottensite | (Na,K)3Sb3+6(Sb3+S3)O9 · 3H2O |
| 2.MA.05 | Cetineite | (K,Na)6Sb3+12(Sb3+S3)2O18(OH)0.5 · 5,5H2O |
| 2.MA.10 | Sarabauite | CaSb3+10S6O10 |
| 2.MA.20 | Thionasilite | Na2Si2S2O3 |
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 Cafeosite
mindat.org URL:
https://www.mindat.org/min-470994.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Cafeosite
Localities for Cafeosite
Showing 1 localities.
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.
Oman (TL) | |
| Bosi et al. (2024) +1 other reference |
