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Malladrite

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About MalladriteHide

Formula:
Na2[SiF6]
Colour:
Pale rose.
Hardness:
3
Specific Gravity:
2.714
Crystal System:
Trigonal
Name:
After Alessandro Malladra (born in Turin, 1865; died in Rome, 1945), professor at the College Mellerio Rosmini-Domodossola; director (1927–1935) of the Vesuvius Observatory.
This page provides mineralogical data about Malladrite.


Classification of MalladriteHide

Approved, 'Grandfathered' (first described prior to 1959)
3.CH.05

3 : HALIDES
C : Complex halides
H : Silicofluorides
11.5.2.1

11 : HALIDE COMPLEXES
5 : AmBX6
8.12.3

8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
12 : Fluorborates (BF'4) and fluosilicates (SiF''6)

Physical Properties of MalladriteHide

Colour:
Pale rose.
Hardness:
Density:
2.714 g/cm3 (Measured)    

Optical Data of MalladriteHide

Type:
Uniaxial (-)
RI values:
nω = 1.313 nε = 1.309
Max Birefringence:
δ = 0.004
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Moderate

Chemical Properties of MalladriteHide

Formula:
Na2[SiF6]
IMA Formula:
Na2SiF6

Crystallography of MalladriteHide

Crystal System:
Trigonal
Cell Parameters:
a = 8.86 Å, c = 5.04 Å
Ratio:
a:c = 1 : 0.569
Unit Cell V:
342.63 ų (Calculated from Unit Cell)
Morphology:
Crystals prismatic [0001] with basal plane and pyramid.

Type Occurrence of MalladriteHide

Geological Setting of Type Material:
Lava deposits on an active volcano.
Associated Minerals at Type Locality:

Other Language Names for MalladriteHide

Common AssociatesHide

Associated Minerals Based on Photo Data:
Avogadrite2 photos of Malladrite associated with Avogadrite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

3.CH.10Bararite(NH4)2[SiF6]Trig. 3m (3 2/m)
3.CH.15Cryptohalite(NH4)2[SiF6]Iso. m3m (4/m 3 2/m) : Fm3m
3.CH.15HieratiteK2[SiF6]Iso. m3m (4/m 3 2/m) : Fm3m
3.CH.20DemartiniteK2[SiF6]Hex. 6mm : P63mc
3.CH.25KnasibfiteK3Na4[SiF6]3[BF4]Orth. mm2 : Imm2

Related Minerals - Dana Grouping (8th Ed.)Hide

11.5.2.2Bararite(NH4)2[SiF6]Trig. 3m (3 2/m)
11.5.2.3DemartiniteK2[SiF6]Hex. 6mm : P63mc

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

8.12.1FerrucciteNa[BF4]Orth.
8.12.2Avogadrite(K,Cs)[BF4]Orth. mmm (2/m 2/m 2/m) : Pnma
8.12.4HieratiteK2[SiF6]Iso. m3m (4/m 3 2/m) : Fm3m
8.12.5Cryptohalite(NH4)2[SiF6]Iso. m3m (4/m 3 2/m) : Fm3m
8.12.6Bararite(NH4)2[SiF6]Trig. 3m (3 2/m)

Other InformationHide

Notes:
Slightly soluble in cold water; slightly more so in hot 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 MalladriteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Stolba (1872) Zeitschrift für anorganische und allgemeine Chemie, Hamburg, Leipzig: 11: 199.
Bertrand (1880) Bulletin de la Société française de Minéralogie: 3: 57.
Raiteri (1922) Reale accademia nazionale dei Lincei, Rendus, Rome: 31: 115.
Zambonini and Carobbi (1926) Reale accademia nazionale dei Lincei, Rendus, Rome: 4: 173.
American Mineralogist (1927): 12: 379.
Collins (1929) Chemical News and Journal of Industrial Science, London: 318: 184.
Carobbi (1933) Periodico de Mineralogia-Roma: 4: 410.
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: 105-106.
Acta Crystallographica (1964): 17: 1408-1412.

Internet Links for MalladriteHide

Localities for MalladriteHide

This 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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for 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 (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Iceland
 
  • Southern Region
Garavelli, A., Balić-Žunić, T., Mitolo, D., Acquafredda, P., Leonardsen, E., Jakobson, S.P. (2010): Heklaite, KNaSiF6, a new fumarolic mineral from Hekla volcano, Iceland. Mineralogical Magazine, 74, 147-157.
Italy (TL)
 
  • Campania
    • Naples Province
      • Somma-Vesuvius Complex
Accad.Lincei.Rend.Cl.Sci.fis.mat.nat., Roma (1926) ser.6, 4, 171-175; 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: 99, 106; Lapis (1994): 5: 13-23, 58.
Russo, M., Punzo, I. (2004): I minerali del Somma-Vesuvio, AMI
  • Sicily
    • Messina Province
      • Eolie Islands (Aeolian Islands)
        • Lipari
          • Vulcano Island
GARAVELLI A., LAVIANO R., VURRO F. (1997): Sublimate deposition from hydrothermal fluids at the Fossa Crater - Vulcano, Italy. - European Journal of Mineralogy - 9, 2, 423-432. [Found in sample tubes only]
Poland
 
  • Upper Silesia (Śląskie)
    • Upper Silesian Coal Basin
      • Rybnik Coal Area
        • Radlin
Łukasz Kruszewski (2012) Unique chloride assemblage of exhalative origin from burning coal-mining dump in Radlin (Rybnik Coal Area, S Poland). Mineralogical Society of Poland Special Papers 40
Russia
 
  • Far-Eastern Region
    • Kamchatka Oblast'
American Mineralogist, Volume 82, pages 1038–1041, 1997
Mineral and/or Locality  
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