Bernalite (original) (raw)

A valid IMA mineral species

About BernaliteHide

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Formula:

Fe(OH)3 · nH2O (n = 0.0 to 0.25)

Colour:

Dark bottle-green to yellow-green; yellowish bottle-green in thin section

Lustre:

Adamantine, Vitreous, Resinous

Crystal System:

Orthorhombic

Name:

Named in honor of John Desmond Bernal (10 May 1901, Nenagh, County Tipperary, Ireland - 15 September 1971, London, England), eminent crystallographer and historian of science. He pioneered the use of X-ray crystallography in molecular biology and determined the structure of graphite. He also investigated the crystal chemistry of iron oxides and hydroxides.

Söhngeite Group.
A highly unusual, pseudo-cubic, bottle-green iron hydroxide. In bernalite, the iron containing octahedra units only share corners, while other iron hydroxides share both corners and edges, resulting in Fe-O distances in bernalite that are more consistent than other iron hydroxides. This causes a low crystal field stabilization energy which results in a green color as compared to the red yellow of other iron hydroxides.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:635:6

8c57f88f-f743-4728-88e5-01b8d598740e

IMA Classification of BernaliteHide

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Type description reference:

Classification of BernaliteHide

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4.FC.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
C : Hydroxides with OH, without H2O; corner-sharing octahedra

6.3.5.3

6 : HYDROXIDES AND OXIDES CONTAINING HYDROXYL
3 : X(OH)3

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Physical Properties of BernaliteHide

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Adamantine, Vitreous, Resinous

Transparency:

Transparent, Opaque

Colour:

Dark bottle-green to yellow-green; yellowish bottle-green in thin section

Fracture:

Irregular/Uneven, Conchoidal

Density:

3.32 g/cm3 (Measured) 3.35 g/cm3 (Calculated)

Optical Data of BernaliteHide

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RI values:

n = 1.92 - 1.94

δ = 0.000

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Chemistry of BernaliteHide

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Mindat Formula:

Fe(OH)3 · nH2O (n = 0.0 to 0.25)

Common Impurities:

C,Pb,Si,Zn

Crystallography of BernaliteHide

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Crystal System:

Orthorhombic

Class (H-M):

m m m _(_2/_m_2/_m_2/m ) - Dipyramidal

Cell Parameters:

a = 7.544 Å, b = 7.56 Å, c = 7.558 Å

Ratio:

a:b:c = 0.998 : 1 : 1

Unit Cell V:

431.05 ų (Calculated from Unit Cell)

Morphology:

Flattened pyramidal crystals, pseudo-octahedral to pseudo-cubic, with slightly concave faces; also skeletal aggregates.

Twinning:

Polysynthetic, crosshatched, observed in thin section, probably pinacoidal.

Comment:

Pseudocubic. Originally described with space group Immm.

Crystal StructureHide

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ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0001607	Bernalite	Birch W D, Pring A, Reller A, Schmalle H W (1993) Bernalite, Fe(OH)3, a new mineral from Broken Hill, New South Wales: Description and structure American Mineralogist 78 827-834		1993	Broken Hill, New South Wales, Australia	0	293

CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Comments:

Recorded on type material

Geological EnvironmentHide

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Type Occurrence of BernaliteHide

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General Appearance of Type Material:

Flattened pyramidal crystals and pseudo-octahedra, to 3 mm.

Place of Conservation of Type Material:

Museum of Victoria, Melbourne, Australia;
South Australian Museum, Adelaide, Australia (No. G17627)

Geological Setting of Type Material:

On a museum specimen from a metamorphosed Pb-Zn deposit, probably from the surface oxidation zone

Associated Minerals at Type Locality:

Reference:

Birch, W. D., Pring, A., Reller, A. and Schmalle, H. W. (1992) Bernalite: a new ferric hydroxide with perovskite structure. Naturwissenschaften: 79: 509-511.

Synonyms of BernaliteHide

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Other Language Names for BernaliteHide

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Relationship of Bernalite to other SpeciesHide

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Other Members of this group:

Common AssociatesHide

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Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

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Other InformationHide

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Health Risks:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for BernaliteHide

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References for BernaliteHide

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Reference List:

Birch, William D., Pring, Allan, Reller, Armin, Schmalle, Helmut W. (1993) Bernalite, Fe(OH)3, a new mineral from Broken Hill, New South Wales: Description and structure. American Mineralogist, 78 (7-8) 827-834

Anthony, John Williams, Bideaux, Richard A., Bladh, Kenneth W., Nichols, Monte C. - Ed. (1997) Handbook of Mineralogy Vol. 3 - Halides, Hydroxides, Oxides. Mineral Data Publishing, Tucson, Arizona. p.1-682.

Localities for BernaliteHide

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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

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- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and 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 (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.