Avogadrite
A valid IMA mineral species - grandfathered
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About Avogadrite
Formula:
(K,Cs)[BF4]
Colour:
Colourless to white, yellowish to reddish when impure, colourless in transmitted light
Specific Gravity:
2.9 (Calculated)
Crystal System:
Orthorhombic
Name:
For Amadeo Avogadro (Turin August 9 1776 - Turin, July 9 1856), Professor of Physics at the University of Turin, Turin, Italy. Remembered for Avogadro's gas law and Avogadro's number.
This page provides mineralogical data about Avogadrite.
Unique Identifiers
Mindat ID:
438
Long-form identifier:
mindat:1:1:438:5
GUID
(UUID V4):
(UUID V4):
46734927-16a2-4cf8-9dca-a74fb64eb6e1
IMA Classification of Avogadrite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
KBF4
Classification of Avogadrite
3.CA.10
3 : HALIDES
C : Complex halides
A : Borofluorides
3 : HALIDES
C : Complex halides
A : Borofluorides
11.2.2.1
11 : HALIDE COMPLEXES
2 : AmBX4
11 : HALIDE COMPLEXES
2 : AmBX4
8.12.2
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
12 : Fluorborates (BF'4) and fluosilicates (SiF''6)
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
12 : Fluorborates (BF'4) and fluosilicates (SiF''6)
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 |
---|---|---|
Avg | 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 Avogadrite
Transparency:
Translucent
Colour:
Colourless to white, yellowish to reddish when impure, colourless in transmitted light
Density:
2.9 g/cm3 (Calculated)
Optical Data of Avogadrite
Type:
Biaxial (-)
RI values:
nα = 1.324 nβ = 1.325 nγ = 1.325
2V:
Measured: 75° , Calculated: 58°
Max Birefringence:
δ = 0.001
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
Dispersion:
r > v, strong
Chemistry of Avogadrite
Mindat Formula:
(K,Cs)[BF4]
Elements listed:
Crystallography of Avogadrite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Pnma
Cell Parameters:
a = 8.6588 Å, b = 5.48 Å, c = 7.0299 Å
Ratio:
a:b:c = 1.58 : 1 : 1.283
Unit Cell V:
333.57 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Octagonal crystals, tabular to platy on {001}, may be elongated along [010] or [100].
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) |
---|---|---|---|---|---|---|---|
0009363 | Avogadrite | Brunton G (1969) The crystal structure of KBF4 Acta Crystallographica B25 2161-2162 | 1969 | 0 | 293 | ||
0012154 | Avogadrite | Clark M J R, Lynton H (1969) Crystal structures of potassium, ammonium, rubidium and cesium tetrafluoroborates Canadian Journal of Chemistry 47 2579-2586 | 1969 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
3.41 Å | (100) |
3.26 Å | (80) |
3.06 Å | (75) |
2.068 Å | (55) |
3.51 Å | (45) |
2.801 Å | (40) |
2.091 Å | (35) |
Comments:
X-ray data of synthetic K[BF4] (ICDD 16-378)
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 7: Great Oxidation Event | <2.4 |
45b : [Other oxidized fumarolic minerals] |
Geological Setting:
Volcanic fumaroles
Type Occurrence of Avogadrite
General Appearance of Type Material:
minute octagonal crystals and dense crusts
Place of Conservation of Type Material:
Natural History Museum, Paris, France (No. 126.148)
Geological Setting of Type Material:
Sublimation products around volcanic fumaroles
Associated Minerals at Type Locality:
Other Language Names for Avogadrite
Common Associates
Associated Minerals Based on Photo Data:
6 photos of Avogadrite associated with Malladrite | Na2[SiF6] |
1 photo of Avogadrite associated with Ferruccite | Na[BF4] |
1 photo of Avogadrite associated with Knasibfite | K3Na4[SiF6]3[BF4] |
1 photo of Avogadrite associated with Verneite | Na2Ca3Al2F14 |
Related Minerals - Strunz-mindat Grouping
3.CA.05 | Ferruccite | Na[BF4] |
3.CA.10 | Barberiite | (NH4)[BF4] |
Other Information
Thermal Behaviour:
The mineral becomes cubic above 273°C.
Notes:
Slightly soluble in water.
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 Avogadrite
mindat.org URL:
https://www.mindat.org/min-438.html
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Please feel free to link to this page.
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References for Avogadrite
Reference List:
Localities for Avogadrite
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).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
Italy (TL) | |
| Palache et al. (1951) |
Russo et al. (2004) | |
Palache et al. (1951) +2 other references | |
| Gramaccioli et al. (2007) |
Russia | |
Anthony (1997) |
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Vesuvius fumaroles, Mount Vesuvius, Somma-Vesuvius Complex, Naples, Campania, Italy