Mindat Logo


This page is currently not sponsored. Click here to sponsor this page.

System:OrthorhombicColour:Colourless to white, ...
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

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:3/B.01-20
Nickel-Strunz 10th (pending) edition ID:3.CA.10

C : Complex halides
A : Borofluorides
Dana 8th edition ID:

2 : AmBX4
Hey's CIM Ref.:8.12.2

8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
12 : Fluorborates (BF'4) and fluosilicates (SiF''6)
mindat.org URL:http://www.mindat.org/min-438.html
Please feel free to link to this page.

Type Occurrence of Avogadrite

Type Locality:Mt Vesuvius, Somma-Vesuvius Complex, Naples Province, Campania, Italy
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)
Year of Discovery:1926
Geological Setting of type material:Sublimation products around volcanic fumaroles
Associated Minerals at type 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 (calculated):2.9 g/cm3

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)
Morphology:Octagonal crystals, tabular to platy on {001}, may be elongated along [010] or [100].
X-Ray Powder Diffraction:
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°
Maximum Birefringence:δ = 0.001

Chart 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

Simplified for copy/paste:(K,Cs)[BF4]
Essential elements:B, F, K
All elements listed in formula:B, Cs, F, K
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

Related Minerals - Nickel-Strunz Grouping):

- +
Related Minerals - Hey's Index Grouping:

- +

Other Names for Avogadrite

Other Languages:

Other Information

Thermal Behaviour:The mineral becomes cubic above 273°C.
Other Information:Slightly soluble in water.
Health Warning: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

Search Engines:
  • Look for Avogadrite on Google
  • Look for Avogadrite images on Google
  • External Links:
  • Look for Avogadrite on Webmineral
  • Look for Avogadrite on Athena Mineralogy
  • Look for Avogadrite on Wikipedia
  • Look for Avogadrite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Avogadrite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Rare and Unusual minerals at Mineralogical Research Company
  • Fine and rare minerals from mintreasure.com
  • Buy from McDougall Minerals
  • High-end worldwide specimens & outstanding customer service
  • rare and unusual minerals mainly crystallized
  • DAKOTA MATRIX offers Cabinet and Rare Species from Worldwide Localities.
  • SpiriferMinerals.com - high quality low prices
  • Top quality minerals from Kristalle of California
  • Fine Minerals from Weinrich Minerals, Inc.
  • Buy rare minerals from Excalibur Minerals
  • The Arkenstone - Fine Minerals
  • Buy from Dave Bunk Minerals
  • Localities for Avogadrite

    The 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. ? 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.
    • 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.
    • Far-Eastern Region
    Anthony, J. W. et al. (1997): Handbook of Mineralogy, Vol. 3, 32
    Mineral and/or Locality  
    Search Google  
    Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
    Current server date and time: September 4, 2014 00:54:11
    Mineral and Locality Search
    and/or Locality:
    Fade toolbar when not in focusFix toolbar to bottom of page
    Hide Social Media Links
    Slideshow frame delay seconds