Mineralogy Database

Olmiite Mineral Data

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General Olmiite Information

Help on Chemical  Formula: Chemical Formula: CaMn[SiO3(OH)](OH)
Help on Composition: Composition: Molecular Weight = 203.44 gm
   Calcium    22.65 %  Ca   31.70 % CaO
   Manganese  22.95 %  Mn   29.64 % MnO
   Iron        0.27 %  Fe    0.35 % FeO
   Silicon    13.81 %  Si   29.53 % SiO2
   Hydrogen    0.99 %  H     8.86 % H2O
   Oxygen     39.32 %  O
             ______        ______ 
             100.00 %      100.08 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca1.15Mn2+0.85Fe2+0.01(SiO3)(OH)2
Help on Environment: Environment: Mn-dominant analogue of poldervaartite
Help on IMA Status: IMA Status: Approved IMA 2006 (Dana # Added)
Help on Locality: Locality: N�Chwaning II mine, Kalahari field, Republic of South Africa Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Filippo Olmi, mineralogist at Centre di Studio per la Minerogenesi ela Geochimica Applicata, Florence, Italy
Help on Synonym: Synonym: IMA2006-026

Olmiite Image

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Comments: Spherical aggregate of prismatic crystals of pinkish tan olmiite..
Location: N'chwaning II Mine, section 5 south stope, 46-47 roof, Kuruman South Africa. Scale: Specimen size 2.5 × 2 × 1.4 cm.
© Fabre Minerals

Olmiite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =1.019:1:1.1394
Help on Cell Dimensions: Cell Dimensions: a = 9.249, b = 9.076, c = 10.342, Z = 8; V = 868.15 Den(Calc)= 3.11
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P bca
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.19(1), 4.14(0.6), 2.361(0.4),2.545(0.35), 2.807(0.35), 2.521(0.3), 2.762(0.3),

Physical Properties of Olmiite

Help on Cleavage: Cleavage: None
Help on Color: Color: Reddish pink.
Help on Density: Density: 3.05
Help on Diaphaneity: Diaphaneity: Transparent
Help on Fracture: Fracture: Brittle - Irregular - Very brittle fracture producing irregular fragments
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Hardness: Hardness: 5-5.5 - Apatite-Knife Blade
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Olmiite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.021 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.001 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2175,KPDmeas= 0.2217,KC= 0.2172
Ncalc = 1.66 - 1.68
Help on Optical Data: Optical Data: Biaxial (+), a=1.663, b=1.672, g=1.694, bire=0.0310, 2V(Calc)=66, 2V(Meas)=71.8. Dispersion r > v.

Calculated Properties of Olmiite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.07 gm/cc
note: Specific Gravity of Olmiite =3.11 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0070012151
Boson Index = 0.9929987849
Help on Photoelectric: Photoelectric: PEOlmiite = 9.18 barns/electron
U=PEOlmiite x rElectron Density= 28.22 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Olmiite is Not Radioactive

Olmiite Classification

Help on  Dana Class: Dana Class: (78)Unclassified silicates
  (78.01)possible nesosilicates
  (78.01.08)Dana Group Poldervaartite (Ca,Mn)2SiO3(OH)2 P bca 2/m 2/m 2/m Olmiite! CaMn[SiO3(OH)](OH) P bca 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 09.AF.90 09 - SILICATES (Germanates)
  09.A - Nesosilicates
  09.AF -Nesosilicates with additional anions;
09.AF.90 Poldervaartite (Ca,Mn)2SiO3(OH)2 P bca 2/m 2/m 2/m
09.AF.90 Olmiite! CaMn[SiO3(OH)](OH) P bca 2/m 2/m 2/m

Other Olmiite Information

Help on References: References: NAME( EurJMin, v71:193) PHYS. PROP.(EurJMin, v71:193) OPTIC PROP.(EurJMin, v71:193)
Help on See Also: See Also: Links to other databases for Olmiite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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Dana No: Strunz No: 09.AF.90





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