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Avogadrite

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Lorenzo Romano Amedeo Carlo Avogadro di Quaregna (Quaregga) e di Cerreto
Formula:
(K,Cs)[BF4]
System:
Orthorhombic
Colour:
Colourless to white, ...
Name:
For Amadeo Avogadro (1776-1856), Professor of Physics at the University of Turin, Turin, Italy.
This page provides mineralogical data about Avogadrite.

Classification of Avogadrite

Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
3.CA.10

3 : HALIDES
C : Complex halides
A : Borofluorides
11.2.2.1

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)
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First Recorded Occurrence of Avogadrite

General Appearance of First Recorded Material:
minute octagonal crystals and dense crusts
Place of Conservation of First Recorded Material:
Natural History Museum, Paris, France (No. 126.148)
Year of Discovery:
1926
Geological Setting of First Recorded Material:
Sublimation products around volcanic fumaroles
Associated Minerals at First Recorded Locality:

Occurrences of Avogadrite

Geological Setting:
Volcanic fumaroles

Physical Properties of Avogadrite

Diaphaneity (Transparency):
Translucent
Colour:
Colourless to white, yellowish to reddish when impure, colourless in transmitted light
Density:
2.9 g/cm3 (Calculated)

Crystallography of Avogadrite

Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Pnma
Cell Parameters:
a = 8.6588Å, b = 5.48Å, c = 7.0299Å
Ratio:
a:b:c = 1.58 : 1 : 1.283
Unit Cell Volume:
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].
X-Ray Powder Diffraction Data:
d-spacingIntensity
3.41 (100)
3.26 (80)
3.06 (75)
2.068 (55)
3.51 (45)
2.801 (40)
2.091 (35)
Comments:
X-ray data of synthetic K[BF4] (ICDD 16-378)

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.
Surface Relief:
Moderate
Dispersion:
r > v, strong

Chemical Properties of Avogadrite

Formula:
(K,Cs)[BF4]
Essential elements:
All elements listed in formula:
Analytical Data:
Partial analysis of material from Vesuvius, Italy, determined on aqueous extracts from mixtures of sublimates.
K (15.2)
Cs (7.0)
B (12.0)

Relationship of Avogadrite to other Species

8.12.1FerrucciteNa[BF4]
8.12.3MalladriteNa2[SiF6]
8.12.4HieratiteK2[SiF6]
8.12.5Cryptohalite(NH4)2[SiF6]
8.12.6Bararite(NH4)2[SiF6]

Other Names for Avogadrite

Name in Other Languages:

Other Information

Thermal Behaviour:
The mineral becomes cubic above 273°C.
Other Information:
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.

References for Avogadrite

Reference List:
Carobbi (1926) Reale accademia nazionale dei Lincei, Rome, Rend.: (6), 4, 382.

Zambonini (1926) Reale accademia nazionale dei Lincei, Rome, Rend.: (6), 3, 644.

Zambonini and Coniglio (1926) Reale accademia nazionale dei Lincei, Rome, Rend.: (6), 3, 521.

American Mineralogist (1927) 12, 232.

Pesce (1930) Gazzetta chimica italiana, Rome: 60: 936.

Finbak and Hassel (1936) Zeitschrift für Physikalische Chemie, Leipzig, Berlin: 32: 433 (isometric polymorph).

Klinkenberg (1937) Recueil des travaux chimiques des Pays-Bas et de la Belgique, Leyden: 56: 36.

Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged: 97-98.

Vlasov, K. A., Ed. (1966): Mineralogy of rare elements, Vol. 2, 65-66.

Brunton, G. (1969): The crystal structure of KBF4. Acta Crystallographica 25, 2161-2162.

Anthony, J. W. et al. (1997): Handbook of Mineralogy, Vol. 3, 32.

Internet Links for Avogadrite

Localities for Avogadrite

map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
(TL) indicates type locality for a valid mineral species. (FRL) indicates first recorded locality for everything else. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
Italy
 
  • Campania
    • Naples Province
      • Somma-Vesuvius Complex
Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 98.
Russo, M., Punzo, I. (2004): I minerali del Somma-Vesuvio, AMI
  • Sicily
    • Messina Province
      • Eolie Islands (Aeolian Islands)
        • Lipari
          • Vulcano Island
GRAMACCIOLI, C.M., CAMPOSTRINI, I. (2007): Demartinite, a new natural polymorph of K2SiF6 from La Fossa crater, Vulcano, Aeolian Islands, Italy. - Canadian Mineralogist - 45, 1275-1280.
Russia
 
  • Far-Eastern Region
Anthony, J. W. et al. (1997): Handbook of Mineralogy, Vol. 3, 32
Mineral and/or Locality  
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