Malladrite Mineral Data

Malladrite Mineral Data +

[New Updates] [Gallery 1] [Gallery 2] [Gallery 3] [Rock Shop Gallery]
Serving the mineral collector and educator community since 1970
Over 900,000 mineral specimens in stock
New minerals acquired weekly - Wright's Rock Shop

General Malladrite Information

Chemical Formula:

Na2SiF6

Composition:

Molecular Weight = 188.06 gm

Sodium 24.45 % Na 32.96 % Na₂O

Silicon 14.93 % Si 31.95 % SiO₂

Fluorine 60.62 % F 60.62 % F

- % F -25.52 % -O=F₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₂SiF₆

Environment:

Sublimate from fumaroles.

IMA Status:

Valid Species (Pre-IMA) 1926

Locality:

Vesuvius, Italy. Link to MinDat.org Location Data.

Name Origin:

Named for Alessandro Malladra (1865-1945), Italian volcanologist, director of the Vesuvius Observatory.

Synonym:

ICSD 16598

PDF 33-1280

Malladrite Image

Images:

Malladrite Avogadrite

Comments: Botryoidal pinkish-white avogadrite with yellow malladrite.
Location: Eruption of 1926, Vesuvius, Campania, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Malladrite Avogadrite

Comments: Yellow-orange crystalline malladrite with pinkish white avogadrite.
Location: Eruption of 1926, Vesuvius, Campania, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Malladrite Crystallography

Axial Ratios:

a:c = 1:0.5688

Cell Dimensions:

a = 8.866, c = 5.043, Z = 3; V = 343.30 Den(Calc)= 2.73

Crystal System:

Trigonal - TrapezohedralH-M Symbol (3 2) Space Group: P 3₂1

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.281(1), 3.325(0.8), 1.795(0.78),

Physical Properties of Malladrite

Color:

Rose, Colorless, White.

Density:

2.714 - 2.755, Average = 2.73

Diaphaniety:

Transparent

Habit:

Crystalline - Fine - Occurs as well-formed fine sized crystals.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

3 - Calcite

Luster:

Vitreous - Greasy

Streak:

white

Optical Properties of Malladrite

Gladstone-Dale:

CI meas= 0.278 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.277 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1139,KPDmeas= 0.1137,KC= 0.1576

Optical Data:

Uniaxial (-), e=1.309, w=1.313, bire=0.0040.

Calculated Properties of Malladrite

Electron Density:

r_electron=2.61 gm/cc
note: r_Malladrite=2.73 gm/cc.

Fermion Index

Fermion Index = 0.00697
Boson Index = 0.99303

Photoelectric:

PE_Malladrite= 1.27 barns/electron
U=PE_Malladrite x r_electron= 3.32 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Malladrite is Not Radioactive

Malladrite Classification

Dana Class:

11.5.2.1 (11)Halide Complexes; Alumino-fluorides

(11.5)where (A)m B (X)6

(11.5.2)Dana Group

11.5.2.1 Malladrite Na2SiF6 P 3₂1 3 2

11.5.2.2 Bararite (NH4)2SiF6 R 3m 3 2/m

Strunz Class:

III/B.02-10 III - Halogenides

III/B - Double halogenides without water, with [BF4]1-,[SiF6]2- and [AlF6]3-

III/B.02 - Mallardite - Bararite series

III/B.02-10 Malladrite Na2SiF6 P 3₂1 3 2

III/B.02-20 Hieratite K2SiF6 F m3m 4/m 3 2/m

III/B.02-30 Cryptohalite (NH4)2SiF6 F m3m 4/m 3 2/m

III/B.02-40 Bararite (NH4)2SiF6 R 3m 3 2/m

Other Malladrite Information

References:

NAME( Ford32) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Malladrite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

Search for Malladrite using:

[ALTAVISTA] [AOL] [About.com] [All-The-Web] [HotBot] [Ixquick] [LookSmart] [MAMMA] [MSN.COM] [Netscape] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Malladrite :
AA Mineral Specimens
B and L Minerals
Dan Weinrich Fine Minerals
Dan Weinrich Auctions
e-Rocks Auctions
Excalibur Minerals
Exceptional Minerals
Fabre Minerals
Greenside Minerals
John Betts Fine Minerals
Masons Minerals
Minernet.it
Mineral News
Mineral of the Month Club
MineralsWeb Fine Minerals
Rockshop.cz Kalat Fine Minerals
T G Fine Minerals
Wrights Rock Shop

Translate Malladrite Mineral Data :

Ask about Malladrite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Malladrite Specimen Label here :

Malladrite

Na2SiF6
Dana No: 11.5.2.1 Strunz No: III/B.02-10
Locality:

Notes: