Demicheleite-(Br)
A valid IMA mineral species
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About Demicheleite-(Br)
Formula:
BiSBr
Colour:
Dark red to black
Lustre:
Sub-Metallic
Specific Gravity:
6.312 (Calculated)
Crystal System:
Orthorhombic
Name:
Originally described as demicheleite, but renamed demicheleite-(Br) after the approval of demicheleite-(Cl), a chlorine-dominant analogue. Honors Vincenzo de Michele (b. 1936), former curator of the Natural History Museum, Milan, Italy, and for its chemical composition.
Type Locality:
Isostructural with:
The Br analogue of demicheleite-(Cl) and demicheleite-(I). Unique combination of elements. The only Bi-Br mineral known. The other sulfide-bromide minerals are 'arzakite' and grechishchevite.
Unique Identifiers
Mindat ID:
32198
Long-form identifier:
mindat:1:1:32198:1
GUID
(UUID V4):
(UUID V4):
76d689a6-1e73-4cf7-9dda-8c4f78359b99
IMA Classification of Demicheleite-(Br)
Classification of Demicheleite-(Br)
2.FC.25
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
F : Sulfides of arsenic, alkalies; sulfides with halide, oxide, hydroxide, H2O
C : With Cl, Br, I (halide-sulfides)
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
F : Sulfides of arsenic, alkalies; sulfides with halide, oxide, hydroxide, H2O
C : With Cl, Br, I (halide-sulfides)
2.15.14.1
2 : SULFIDES
15 : Chlor-sulfides
2 : SULFIDES
15 : Chlor-sulfides
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 |
|---|---|---|
| Dem-Br | 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 Demicheleite-(Br)
Sub-Metallic
Transparency:
Translucent
Colour:
Dark red to black
Streak:
Red
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
None observed
Density:
6.312 g/cm3 (Calculated)
Chemistry of Demicheleite-(Br)
Mindat Formula:
BiSBr
Elements listed:
Crystallography of Demicheleite-(Br)
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Pnma
Cell Parameters:
a = 8.0424 Å, b = 9.8511 Å, c = 4.0328 Å
Ratio:
a:b:c = 0.816 : 1 : 0.409
Unit Cell V:
319.50 ų (Calculated from Unit Cell)
Morphology:
Type material: prismatic {110} and {210}, terminated by minor faces of another prism {011}, a pinacoid {010}, and a bipyramid {111}.
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) |
|---|---|---|---|---|---|---|---|
| 0004679 | Demicheleite-(Br) | Demartin F, Gramaccioli C M, Campostrini I, Orlandi P (2008) Demicheleite, BiSBr, a new mineral from La Fossa crater, Vulcano, Aeolian Islands, Italy American Mineralogist 93 1603-1607 |  | 2008 | La Fossa crater, Vulcano, Aeolian Islands, Italy | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.220 Å | (68) |
| 3.740 Å | (62) |
| 3.721 Å | (44) |
| 2.909 Å | (100) |
| 2.429 Å | (43) |
| 2.036 Å | (47) |
| 1.865 Å | (63) |
| 1.774 Å | (88) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 11 : Volcanic fumarole minerals; reduced phases (see also #45) |
Type Occurrence of Demicheleite-(Br)
General Appearance of Type Material:
Well-formed, prismatic translucent crystals up to 0.5 mm in size.
Place of Conservation of Type Material:
Department of Structural Chemistry and Inorganic Stereochemistry, University of Milan, Italy, reference collection 2007-01.
Geological Setting of Type Material:
An active high-temperature fumarole, in an altered pyroclastic breccia.
Associated Minerals at Type Locality:
Synonyms of Demicheleite-(Br)
Demicheleite (in part)
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 2.FC. | Demicheleite-(I) | BiSI |
| 2.FC.05 | Djerfisherite | K6(Fe,Cu,Ni)25S26Cl |
| 2.FC.05 | Thalfenisite | Tl6(Fe,Ni,Cu)25S26Cl |
| 2.FC.05 | Owensite | (Ba,Pb)6(Cu,Fe,Ni)25S27 |
| 2.FC.05 | Cu-djerfisherite | K6(Cu,Fe)25S26Cl |
| 2.FC.05 | Zoharite | (Ba,K)6(Fe,Cu,Ni)25S27 |
| 2.FC.05 | Gmalimite | K6◻Fe2+24S27 |
| 2.FC.10 | Bartonite | K6Fe20S26S |
| 2.FC.10 | Chlorbartonite | K6Fe24S26(Cl,S) |
| 2.FC.15a | Arzakite | Hg2+3S2(Br,Cl)2 |
| 2.FC.15a | Corderoite | Hg2+3S2Cl2 |
| 2.FC.15c | Grechishchevite | Hg2+3S2(Br,Cl,I)2 |
| 2.FC.15a | Lavrentievite | Hg2+3S2(Cl,Br)2 |
| 2.FC.15d | Radtkeite | Hg2+3S2ICl |
| 2.FC.15b | Kenhsuite | Hg2+3S2Cl2 |
| 2.FC.20a | Capgaronnite | AgHgClS |
| 2.FC.20c | Perroudite | Hg5Ag4S5(I,Br)2Cl2 |
| 2.FC.20b | Iltisite | HgAgSCl |
| 2.FC.20d | Hanauerite | AgHgSI |
| 2.FC.25 | Demicheleite-(Cl) | BiSCl |
Fluorescence of Demicheleite-(Br)
Not fluorescent
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 Demicheleite-(Br)
mindat.org URL:
https://www.mindat.org/min-32198.html
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References for Demicheleite-(Br)
Localities for Demicheleite-(Br)
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.
Czech Republic | |
| Dalibor Matýsek |
| Dalibor Matýsek | |
Italy (TL) | |
| Demartin et al. (2008) |
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La Fossa crater, Vulcano Island, Lipari, Eolie Islands, Metropolitan City of Messina, Sicily, Italy