Demartinite
A valid IMA mineral species
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About Demartinite
Francesco Demartin
Formula:
K2[SiF6]
Colour:
Colorless
Specific Gravity:
2.85
Crystal System:
Hexagonal
Name:
After Francesco Demartin (born 1953), professor of General and Inorganic Chemistry and Stechiometry at the University of Milan, Italy. He has made significant contributions to the chemistry of metallic clusters in organometallic compounds and to the crystal structure of Alpine rare-earth minerals and uranium minerals.
Type Locality:
Dimorph of:
This page provides mineralogical data about Demartinite.
Unique Identifiers
Mindat ID:
30908
Long-form identifier:
mindat:1:1:30908:6
GUID
(UUID V4):
(UUID V4):
524a1a84-f255-48f1-9e8b-b308a6b2e26b
IMA Classification of Demartinite
Classification of Demartinite
3.CH.20
3 : HALIDES
C : Complex halides
H : Silicofluorides
3 : HALIDES
C : Complex halides
H : Silicofluorides
11.5.2.3
11 : HALIDE COMPLEXES
5 : AmBX6
11 : HALIDE COMPLEXES
5 : AmBX6
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 |
|---|---|---|
| Dma | 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 Demartinite
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Density:
2.85 g/cm3 (Measured) 2.87 g/cm3 (Calculated)
Optical Data of Demartinite
Type:
Uniaxial (-)
RI values:
nω = 1.350(5) nε = 1.340(5)
Max Birefringence:
δ = 0.010
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Pleochroism:
Non-pleochroic
Chemistry of Demartinite
Mindat Formula:
K2[SiF6]
Elements listed:
Crystallography of Demartinite
Crystal System:
Hexagonal
Class (H-M):
6mm - Dihexagonal Pyramidal
Space Group:
P63mc
Cell Parameters:
a = 5.6461(8) Å, c = 9.2322(18) Å
Ratio:
a:c = 1 : 1.635
Unit Cell V:
254.88 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Hexagonal pyramidal crystals. The observed forms are the pedion {001} and the hexagonal pyramid {112}.
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) |
|---|---|---|---|---|---|---|---|
| 0006157 | Demartinite | Gramaccioli C M, Campostrini I (2007) Demartinite, a new polymorph of K2SiF6 from La Fossa Crater, Vulcano, Aeolian Islands, Italy The Canadian Mineralogist 45 1275-1280 |  | 2007 | La Fossa Crater, Vulcano Island, Aeolian Archipelago, Sicily, Italy | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.90 Å | (25) |
| 4.62 Å | (75) |
| 4.32 Å | (43) |
| 2.358 Å | (22) |
| 2.301 Å | (100) |
| 2.155 Å | (54) |
| 1.909 Å | (14) |
| 1.403 Å | (13) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45b : [Other oxidized fumarolic minerals] |
Type Occurrence of Demartinite
General Appearance of Type Material:
Colorless hexagonal pyramidal crystals up to 0.3 mm across.
Place of Conservation of Type Material:
State University of Milan, Italy, number 2006-1.
Geological Setting of Type Material:
From a fumarole, on a fragment of altered pyroclastic breccia.
Associated Minerals at Type Locality:
Synonyms of Demartinite
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 3.CH.05 | Malladrite | Na2[SiF6] |
| 3.CH.10 | Bararite | (NH4)2[SiF6] |
| 3.CH.15 | Cryptohalite | (NH4)2[SiF6] |
| 3.CH.15 | Hieratite | K2[SiF6] |
| 3.CH.25 | Knasibfite | K3Na4[SiF6]3[BF4] |
| 3.CH.30 | Heklaite | KNaSiF6 |
Other Information
Notes:
Not hygroscopic.
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 Demartinite
mindat.org URL:
https://www.mindat.org/min-30908.html
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Please feel free to link to this page.
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References for Demartinite
Localities for Demartinite
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.
Italy (TL) | |
| |
Russia | |
|
Quick NavTopAbout DemartiniteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Vulcano Island, Lipari, Eolie Islands, Metropolitan City of Messina, Sicily, Italy