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Malladrite

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Huelva, Andalusia, Spain
© 2008, JGW

Formula:
Na
 
2
[SiF
 
6
]
System:TrigonalColour:Pale rose.
Hardness:3
Name:After Alessandro Malladra, Director, Vesuvius Observatory.
This page provides mineralogical data about Malladrite.

Classification of Malladrite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:3/B.02-10
Nickel-Strunz 10th (pending) edition ID:3.CH.05

3 : HALIDES
C : Complex halides
H : Silicofluorides
Dana 8th edition ID:11.5.2.1

11 : HALIDE COMPLEXES
5 : AmBX6
Hey's CIM Ref.:8.12.3

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

Type Locality:Mt. Vesuvius, Somma-Vesuvius Complex, Naples Province, Campania, Italy
Year of Discovery:1926
Geological Setting of type material:Lava deposits on an active volcano.
Associated Minerals at type locality:
SalammoniacHieratiteFerrucciteAvogadrite

Physical Properties of Malladrite

Colour:Pale rose.
Hardness (Mohs):3
Density (measured):2.714 g/cm3

Crystallography of Malladrite

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

Optical Data of Malladrite

Type:Uniaxial (-)
RI values: nω = 1.313 nε = 1.309
Maximum Birefringence:δ = 0.004

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate

Chemical Properties of Malladrite

Formula:
Na
 
2
[SiF
 
6
]
Essential elements:F, Na, Si
All elements listed in formula:F, Na, Si

Relationship of Malladrite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
3.CH.10Bararite
(NH
 
4
)
 
2
[SiF
 
6
]
3.CH.15Cryptohalite
(NH
 
4
)
 
2
[SiF
 
6
]
3.CH.15Hieratite
K
 
2
[SiF
 
6
]
3.CH.20Demartinite
K
 
2
[SiF
 
6
]
3.CH.25Knasibfite
K
 
3
Na
 
4
[SiF
 
6
]
 
3
[BF
 
4
]
Related Minerals - Hey's Index Grouping:

- +
8.12.1Ferruccite
Na[BF
 
4
]
8.12.2Avogadrite
(K,Cs)[BF
 
4
]
8.12.4Hieratite
K
 
2
[SiF
 
6
]
8.12.5Cryptohalite
(NH
 
4
)
 
2
[SiF
 
6
]
8.12.6Bararite
(NH
 
4
)
 
2
[SiF
 
6
]

Other Names for Malladrite

Other Languages:
German:Malladrit
Spanish:Malladrita

Other Information

Other Information:Slightly soluble in cold water; slightly more so in hot 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 Malladrite

Reference List: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 Malladrite

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    Localities for Malladrite

    Hide Locality List
    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.
    Italy
     
    • 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
        • Lipari
          • Eolie Islands (Aeolian Islands)
            • 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]
    Russia
     
    • Far-Eastern Region
      • Kamchatka Oblast'
    Mineral and/or Locality
    Google
     
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