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Unnamed (OH-analogue of humite)

Valid as an unnamed mineral
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06635870017272473476785.jpg
Unnamed (OH-analogue of humite), etc.

Akhmatov mine, Magnitka, Kusinsky District, Chelyabinsk Oblast, Russia
06635870017272473476785.jpg
Unnamed (OH-analogue of humite), etc.

Akhmatov mine, Magnitka, Kusinsky District, Chelyabinsk Oblast, Russia
06635870017272473476785.jpg
Unnamed (OH-analogue of humite), etc.

Akhmatov mine, Magnitka, Kusinsky District, Chelyabinsk Oblast, Russia
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About Unnamed (OH-analogue of humite)Hide

Formula:
Mg7(SiO4)3(OH)2
Colour:
Pale yellow-orange
Crystal System:
Orthorhombic
Also known as a synthetic material (Wunder et al., 1995). Forms a series with the F-dominant end-member humite; the natural material contains ~0.44 apfu F.


Unique IdentifiersHide

Mindat ID:
470721
Long-form identifier:
mindat:1:1:470721:5

IMA Classification of Unnamed (OH-analogue of humite)Hide

IMA status notes:
Unnamed (probably valid)

Classification of Unnamed (OH-analogue of humite)Hide

Strunz-mindat (2026):
9.AF.50

9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination

Physical Properties of Unnamed (OH-analogue of humite)Hide

Transparency:
Transparent
Colour:
Pale yellow-orange

Optical Data of Unnamed (OH-analogue of humite)Hide

Type:
Biaxial (+)
Dispersion:
weak; r > v
Optical Extinction:
parallel
Pleochroism:
Weak
Comments:
very weak near-colorless/very pale yellow pleochroism
Comments:
~0.020 (2nd order blue) birefringence

Chemistry of Unnamed (OH-analogue of humite)Hide

Mindat Formula:
Mg7(SiO4)3(OH)2
Element Weights:
Element% weight
O46.626 %
Mg35.415 %
Si17.539 %
H0.420 %

Calculated from ideal end-member formula.
O
Mg
Si
H
Elements listed:
H, Mg, O, Si - search for minerals with similar chemistry

Chemical AnalysisHide

Oxide wt%:
 1
P2O50.01 %
SiO236.55 %
TiO20.33 %
Al2O30.01 %
B2O3 (estimated)0.32 %
Fe2O3*0.50 %
FeO*0.55 %
MnO0.08 %
ZnO0.01 %
MgO57.19 %
CaO0.01 %
SrO0.01 %
F1.72 %
H2O (by stoichiometry)2.97 %
-O=F-0.73 %
Total:99.53 %
Empirical formulas:
Sample IDEmpirical Formula
1(Mg6.90Fe2+0.04Fe3+0.03Ti0.02Mn2+0.01)[Si0.99B0.01O4]3((OH)1.52F0.44O0.04)
Sample references:
IDLocalityReferenceNotes
1Akhmatov mine, Magnitka, Kusinsky District, Chelyabinsk Oblast, Russia
Frank K. Mazdab collection; sample FKM-426; https://www.rockptx.com/fkm-426-to-fkm-450/#FKM-426
Unnamed (OH-analogue of humite), or "hydroxylhumite", occurs as abundant pale yellow-orange clusters of crystals in a dolomitic marble, with ludwigite and minor magnetite. In thin section, the mineral is very weakly pleochroic in near-colorless to very pale yellow in PPL. In XP the mineral shows parallel extinction, 2nd order blue birefringence (~0.020), and is B(+) with a 2V° of ~70°±5°. Chemical analysis by EPMA (WDS). *All Fe initially measured as Fe2+; Fe3+ (and Fe2O3) calculated from charge balance, but note that the very small amount of Fe present in the sample results in potentially large errors in Fe3+/∑Fe estimation. H2O calculated from stoichiometry; O in the OH site = 2*Ti. Estimated B2O3 (~1000 ppm B) added in to improve IV-site occupancy and analytical total (this is slated to be verified by ICP-MS and will be updated as necessary).

Crystallography of Unnamed (OH-analogue of humite)Hide

Crystal System:
Orthorhombic

First Recorded Occurrence of Unnamed (OH-analogue of humite)Hide

Relationship of Unnamed (OH-analogue of humite) to other SpeciesHide

Member of:
Humite Subgroup > Humite Group
Other Members of Humite Subgroup:
ChondroditeMg5(SiO4)2F2Mon. 2/m : P21/b
ClinohumiteMg9(SiO4)4F2Mon. 2/m : P21/b
HumiteMg7(SiO4)3F2Orth. mmm(2/m2/m2/m) : Pnma
HydroxylchondroditeMg5(SiO4)2(OH)2Mon. 2/m : P21/b
HydroxylclinohumiteMg9(SiO4)4(OH)2Mon. 2/m : P21/b
NorbergiteMg3(SiO4)F2Orth. mmm(2/m2/m2/m)

Common AssociatesHide

Associations Based on Photo Data:
1 photo of Unnamed (OH-analogue of humite) associated with LudwigiteMg2Fe3+(BO3)O2
1 photo of Unnamed (OH-analogue of humite) associated with DolomiteCaMg(CO3)2
1 photo of Unnamed (OH-analogue of humite) associated with MagnetiteFe2+Fe3+2O4

Related Minerals - Strunz-mindat GroupingHide

9.AF.ChegemiteCa7(SiO4)3(OH)2Orth. mmm(2/m2/m2/m)
9.AF.Jingwenite-(Y)YAlV4+(SiO4)O2(OH)2Mon. 2/m
9.AF.BarwooditeMn2+6Nb5+(SiO4)2O3(OH)3Trig. 3 : P3
9.AF.05SillimaniteAl2(SiO4)OOrth. mmm(2/m2/m2/m)
9.AF.05'Xenolite'Al10Si8O31
9.AF.10KanonaiteMn3+Al(SiO4)OOrth. mmm(2/m2/m2/m) : Pnnm
9.AF.10AndalusiteAl2(SiO4)OOrth. mmm(2/m2/m2/m) : Pnnm
9.AF.15KyaniteAl2(SiO4)OTric. 1 : P1
9.AF.20KrieseliteAl2(GeO4)F2Orth. mmm(2/m2/m2/m) : Pnma
9.AF.20MulliteAl4+2xSi2-2xO10-xOrth. mmm(2/m2/m2/m) : Pbam
9.AF.23BoromulliteAl9BSi2O19Orth. mm2 : Cmc21
9.AF.25YoderiteMg(Al,Fe3+)3(SiO4)2O(OH)Mon. 2/m : P21/m
9.AF.30ZincostauroliteZn2Al9Si4O23(OH)Mon. 2/m : B2/m
9.AF.30StauroliteFe2+2Al9Si4O23(OH)Mon. 2/m : B2/m
9.AF.30MagnesiostauroliteMg(Mg,Li)3(Al,Mg)18Si8O44(OH)4Mon. 2/m : B2/m
9.AF.35TopazAl2(SiO4)(F,OH)2Orth. mmm(2/m2/m2/m)
9.AF.40NorbergiteMg3(SiO4)F2Orth. mmm(2/m2/m2/m)
9.AF.45ChondroditeMg5(SiO4)2F2Mon. 2/m : P21/b
9.AF.45KumtyubeiteCa5(SiO4)2F2Mon. 2/m : P21/b
9.AF.45ReinhardbraunsiteCa5(SiO4)2(OH,F)2Mon. 2/m : P21/b
9.AF.45HydroxylchondroditeMg5(SiO4)2(OH)2Mon. 2/m : P21/b
9.AF.45AlleghanyiteMn2+5(SiO4)2(OH)2Mon. 2/m : P21/b
9.AF.50'Unnamed (Ca-analogue of Humite)'Ca7(SiO4)4F2Orth. mmm(2/m2/m2/m)
9.AF.50HumiteMg7(SiO4)3F2Orth. mmm(2/m2/m2/m) : Pnma
9.AF.50ManganhumiteMn2+7(SiO4)3(OH)2Orth. mmm(2/m2/m2/m)
9.AF.50FluorchegemiteCa7(SiO4)3F2 Orth. mmm(2/m2/m2/m)
9.AF.55HydroxylclinohumiteMg9(SiO4)4(OH)2Mon. 2/m : P21/b
9.AF.55ClinohumiteMg9(SiO4)4F2Mon. 2/m : P21/b
9.AF.55SonoliteMn2+9(SiO4)4(OH)2Mon. 2/m : P21/b
9.AF.60LeucophoeniciteMn2+7(SiO4)3(OH)2Mon. 2/m : P21/b
9.AF.65RibbeiteMn2+5(SiO4)2(OH)2Orth. mmm(2/m2/m2/m)
9.AF.70JerrygibbsiteMn2+9(SiO4)4(OH)2Orth. mmm(2/m2/m2/m) : Pbcn
9.AF.75FranciscaniteMn2+6(V5+,◻)2(SiO4)2(O,OH)6Trig. 3 : P3
9.AF.75ScorticoiteMn6(Sb,◻)Σ2(SiO4)2O3(OH)3Trig. 3 : P3
9.AF.75WeliniteMn2+6(W6+,Mg)2(SiO4)2(O,OH)6Trig. 3 : P3
9.AF.75ÖrebroiteMn2+3(Sb5+,Fe3+)(SiO4)(O,OH)3Trig. 3 : P3
9.AF.80EllenbergeriteMg6(Mg,Ti,Zr,◻)2(Al,Mg)6Si8O28(OH)10Hex. 6 : P63
9.AF.85MagnesiochloritoidMgAl2O(SiO4)(OH)2Mon. 2/m : B2/b
9.AF.85OttréliteMn2+Al2O(SiO4)(OH)2Mon.
9.AF.85ChloritoidFe2+Al2O(SiO4)(OH)2Mon. 2/m : B2/b
9.AF.90OlmiiteCaMn2+[SiO3(OH)](OH)Orth. mmm(2/m2/m2/m) : Pbca
9.AF.90PoldervaartiteCaCa[SiO3(OH)](OH)Orth. mmm(2/m2/m2/m) : Pbca
9.AF.95Pilawite-(Y)Ca2Y2Al4(SiO4)4O2(OH)2Mon. 2/m : P21/b

Other InformationHide

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 Unnamed (OH-analogue of humite)Hide

References for Unnamed (OH-analogue of humite)Hide

Localities for Unnamed (OH-analogue of humite)Hide

Showing 1 localities.

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.
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Locality ListHide

- 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.
Russia (FRL)
 
  • Chelyabinsk Oblast
    • Kusinsky District
      • Magnitka
Frank K. Mazdab collection +2 other references
Quick NavTopAbout Unnamed (OH-analogue of humite)Unique IdentifiersIMA Classification Classification Physical Properties Optical Data Chemistry Chemical AnalysisCrystallography First Recorded Occurrence RelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
 
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