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⇱ Bredigite: Mineral information, data and localities.

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Bredigite

A valid IMA mineral species - grandfathered
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About BredigiteHide

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Formula:
Ca7Mg(SiO4)4
Colour:
Colorless, grey
Lustre:
Vitreous
Specific Gravity:
3.42
Crystal System:
Orthorhombic
Name:
Named in honor of Dr. Max Albrecht Bredig (20 June 1902 - 21 November 1977), physical chemist, who studied the polymorphism of Ca2SiO4. Dr. Bredig was former Associate Director of the Chemistry Division Oak Ridge National Laboratory, and expert in the chemistry of molten salts and chemistry of the solid state, especially high temperature and crystal chemistry.
Anthropogenic "Ca7MgSi4O16" is described by Žáček et al. (2005).


Unique IdentifiersHide

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Mindat ID:
762
Long-form identifier:
mindat:1:1:762:9

IMA Classification of BredigiteHide

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Approved, 'Grandfathered' (first described prior to 1959)
First published:
1948

Classification of BredigiteHide

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9.AD.20

9 : SILICATES (Germanates)
A : Nesosilicates
D : Nesosilicates without additional anions; cations in [6] and/or greater coordination
51.4.1.1

51 : NESOSILICATES Insular SiO4 Groups Only
4 : Insular SiO4 Groups Only with cations in [6] and >[6] coordination
14.5.7

14 : Silicates not Containing Aluminum
5 : Silicates of Ca

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.

SymbolSourceReference
BdiIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of BredigiteHide

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Vitreous
Transparency:
Transparent
Colour:
Colorless, grey
Streak:
White
Cleavage:
Distinct/Good
Distinct on {130}
Density:
3.42 g/cm3 (Measured)    3.32 g/cm3 (Calculated)

Optical Data of BredigiteHide

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Type:
Biaxial (+)
RI values:
nα = 1.712 nβ = 1.716 nγ = 1.725
2V:
Measured: 30° , Calculated: 68°
Max. Birefringence:
δ = 0.013
Based on recorded range of RI values above.

Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.

Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.

Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.

Surface Relief:
Moderate
Dispersion:
relatively strong
Pleochroism:
Visible
Comments:
In thick sections, X = pale violet; Y = Z = colorless to pale green. X=b, Y=a, Z=c.

Chemistry of BredigiteHide

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Mindat Formula:
Ca7Mg(SiO4)4
Element Weights:
Element% weight
Ca41.675 %
O38.027 %
Si16.688 %
Mg3.611 %

Calculated from ideal end-member formula.
Common Impurities:
Ti,Fe,Mn,Ba,F

Crystallography of BredigiteHide

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Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Space Group:
Pnn2
Cell Parameters:
a = 10.909(9) Å, b = 18.34(1) Å, c = 6.739(9) Å
Ratio:
a:b:c = 0.595 : 1 : 0.367
Unit Cell V:
1,348.28 ų (Calculated from Unit Cell)
Z:
4
Twinning:
Simple contact and cyclical on {110}.

Crystal StructureHide

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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0000494BredigiteMoore P B, Araki T (1976) The crystal structure of bredigite and the genealogy of some alkaline earth orthosilicates American Mineralogist 61 74-87👁 Image
19760293
CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

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Powder Diffraction Data:
d-spacingIntensity
2.730 Å(100)
2.663 Å(100)
2.259 Å(80)
1.923 Å(80)
2.067 Å(60)
1.574 Å(60)
1.554 Å(60)

Geological EnvironmentHide

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Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Stage 3a: Earth’s earliest Hadean crust>4.50
9 : Lava/xenolith minerals (hornfels, sanidinite facies)
High-? alteration and/or metamorphism
31 : Thermally altered carbonate, phosphate, and iron formations
Stage 5: Initiation of plate tectonics<3.5-2.5
40 : Regional metamorphism (greenschist, amphibolite, granulite facies)
Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere<0.6
50 : Coal and/or oil shale minerals<0.36
51 : Pyrometamorphic minerals (see also #54 and #56)<0.36
Stage 10b: Anthropogenic minerals<10 Ka
54 : Coal and other mine fire minerals (see also #51 and #56)
56 : Slag and smelter minerals (see also #51 and #55)

Type Occurrence of BredigiteHide

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General Appearance of Type Material:
Crystals are squat, barrel- or boat-shaped, with pseudohexagonal cross sections, or as slender prismatic crystals, to 2mm
Place of Conservation of Type Material:
The Natural History Museum, London, England, 1956, 385.
Geological Setting of Type Material:
Type specimen was from slag (Middlesbrough type specimen of Tilley and Vincent)
Associated Minerals at Type Locality:

Other Language Names for BredigiteHide

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Dutch:Bredigiet
German:Bredigit
Spanish:Bredigita

Common AssociatesHide

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Associated Minerals Based on Photo Data:
1 photo of Bredigite associated with SpurriteCa5(SiO4)2(CO3)

Related Minerals - Strunz-mindat GroupingHide

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9.AD.AdrianiteCa12(Al4Mg3Si7)O32Cl6Iso. 43m : I43d
9.AD.05LarniteCa2SiO4Mon. 2/m
9.AD.10Calcio-olivineCa2SiO4Orth. mmm(2/m2/m2/m)
9.AD.15MerwiniteCa3Mg(SiO4)2Mon. 2/m : P21/b
9.AD.25MidbariteCa3Mg2(V2Si)O12Iso. m3m(4/m32/m)
9.AD.25Menzerite-(Y)(Y2Ca)Mg2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25UvaroviteCa3Cr2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25EltyubyuiteCa12Fe3+10Si4O32Cl6Iso. 43m : I43d
9.AD.25EringaiteCa3Sc2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25HenritermieriteCa3Mn3+2(SiO4)2[◻(OH)4]Tet. 4/mmm(4/m2/m2/m) : I41/acd
9.AD.25 vaHydrougrandite(Ca,Mg,Fe2+)3(Fe3+,Al)2[(OH)4(SiO4)2]Iso.
9.AD.25CalderiteMn2+3Fe3+2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25NikmelnikoviteCa12(Fe2+Fe3+3Al3◻)[SiO4]6[◻(OH)4]5◻4Trig. 3 : R3
9.AD.25HutcheoniteCa3Ti2(SiO4)(AlO4)2Iso. m3m(4/m32/m) : Ia3d
9.AD.25Wadalite(Ca,Mg)6(Al,Fe3+)4((Si,Al)O4)3O4Cl3Iso. 43m : I43d
9.AD.25RubiniteCa3Ti3+2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25KerimasiteCa3Zr2(SiO4)(Fe3+O4)2Iso. m3m(4/m32/m) : Ia3d
9.AD.25HoltstamiteCa3Al2(SiO4)2[◻(OH)4]Tet. 4/mmm(4/m2/m2/m) : I41/acd
9.AD.25SpessartineMn2+3Al2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25ToturiteCa3Sn2(SiO4)(Fe3+O4)2Iso. m3m(4/m32/m) : Ia3d
9.AD.25KimzeyiteCa3Zr2(SiO4)(AlO4)2Iso. m3m(4/m32/m) : Ia3d
9.AD.25KhohariteMg3Fe3+2(SiO4)3
9.AD.25IrinarassiteCa3Sn2(SiO4)(AlO4)2Iso. m3m(4/m32/m) : Ia3d
9.AD.25KnorringiteMg3Cr2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25GoldmaniteCa3V3+2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25BlythiteMn2+3Mn3+2[SiO4]3
9.AD.25SkiagiteFe2+3Fe3+2[SiO4]3
9.AD.25UM1984-37-SiO:CrMnMn2+3Cr3+2(SiO4)3
9.AD.25AlmandineFe2+3Al2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25 vaYamatoite(Mn2+,Ca)3(V3+,Al)2(SiO4)3Iso.
9.AD.25MomoiiteMn2+3V3+2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25GrossularCa3Al2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25AndraditeCa3Fe3+2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25MorimotoiteCa3(TiFe2+)(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25MajoriteMg3(MgSi)(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25PyropeMg3Al2(SiO4)3Iso. m3m(4/m32/m) : Ia3d
9.AD.25SchorlomiteCa3Ti2(SiO4)(Fe3+O4)2Iso. m3m(4/m32/m) : Ia3d
9.AD.30HafnonHf(SiO4)Tet. 4/mmm(4/m2/m2/m) : I41/amd
9.AD.30ZirconZr(SiO4)Tet. 4/mmm(4/m2/m2/m) : I41/amd
9.AD.30CoffiniteU(SiO4) · nH2OTet. 4/mmm(4/m2/m2/m) : I41/amd
9.AD.30ThoriteTh(SiO4)Tet. 4/mmm(4/m2/m2/m) : I41/amd
9.AD.30 vaAuerlitenear Th(Si,P)O4
9.AD.30Stetindite-(Ce)Ce(SiO4)Tet. 4/mmm(4/m2/m2/m) : I41/amd
9.AD.35Tombarthite-(Y)Y4(Si,H4)4O12-x(OH)4+2xMon.
9.AD.35HuttoniteThSiO4Mon. 2/m
9.AD.40EulytineBi4(SiO4)3Iso. 43m : I43d
9.AD.45ReiditeZr(SiO4)Tet. 4/m : I41/a
9.AD.55JeffbeniteMg3Al2Si3O12Tet. 42m : I42d

Other InformationHide

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Notes:
Dissolves readily in the weakest acids, leaving a silica pseudomorph, gives no effervescence, and yields abundant evidence of calcium.
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 BredigiteHide

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mindat.org URL:
https://www.mindat.org/min-762.html
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References for BredigiteHide

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Reference List:

Localities for BredigiteHide

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This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the 👁 Image
symbol to view information about a locality. The 👁 Image
symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

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👁 Image
- This locality has map coordinates listed. 👁 Image
- This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. 👁 Image
- Good crystals or important locality for species. 👁 Image
- 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.
Czech Republic
  • Ústí nad Labem Region
    • Teplice District
      • Zabrušany
Žáček et al. (2011)
Georgia
  • South Ossetia
    • Kel’ volcanic area
      • Shadil-Khokh volcano
Galuskina et al. (2015) +1 other reference
Germany
  • Rhineland-Palatinate
    • Mayen-Koblenz
      • Mayen
        • Seekante
Skrzyńska et al. (2023)
      • Vordereifel
        • Ettringen
Blass et al. (1998)
Sharygin (2012)
in the collection of Christof Schäfer
in the collection of Christof Schäfer
    • Vulkaneifel
      • Daun
        • Üdersdorf
Blaß et al. (2014)
Israel
  • Southern District
    • Beersheba Subdistrict
      • Arad
Kahlenberg et al. (2019)
      • Tamar Regional Council
Sharygin et al. (2008)
Jordan
  • Amman Governorate
    • Transjordan Plateau
      • Daba-Siwaqa complex
        • Hashem region
          • Lisdan-Siwaga Fault
            • Siwaga
              • Tulul al Hammam
Sokol +9 other references
Middle East
Gross (1977)
Russia
  • Irkutsk Oblast
    • Narin-Kunta
Armbruster et al. (2011) +1 other reference
  • Krasnoyarsk Krai
    • Evenkiysky District
Sokol et al. (2019) +2 other references
UK
  • Northern Ireland
    • County Antrim
Mineralogical Society of America - ...
      • Larne
        • Glenoe
Sabine et al. (1985)
Tilley et al. (1948) +2 other references
Tindle (2008)
    • Highland
      • Caol and Mallaig
        • Isle of Muck
American Mineralogist: 33: 786
      • Fort William and Ardnamurchan
        • Ardnamurchan
American Mineralogist 35:1080 +1 other reference
USA
  • Texas
    • Brewster County
      • Christmas Mountains
Rocks & Minerals (1991)
    • Culberson County
      • Apache Peak area
Rocks & Minerals: 66 (3) +1 other reference
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