Mineralogy Database

Tephroite Mineral Data

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General Tephroite Information

Help on Chemical  Formula: Chemical Formula: Mn2SiO4
Help on Composition: Composition: Molecular Weight = 201.96 gm
   Manganese  54.41 %  Mn   70.25 % MnO
   Silicon    13.91 %  Si   29.75 % SiO2
   Oxygen     31.69 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Mn2+2(SiO4)
Help on Environment: Environment: Contact metamorphism of manganese bearing rocks.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1823
Help on Locality: Locality: Franklin and Sparta, New Jersey, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: From the Greek tephros - "ash gray" for its color.
Help on Name Pronunciation: Name Pronunciation: Tephroite + Pronunciation Say TEPHROITE
Help on Synonym: Synonym: ICSD 100433
  PDF 35-748
 

Tephroite Image

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  Tephroite

Comments: Sharp crystals of tephroite to 1.2 cm across.
Location: N'Chwaning Mine, Kalahari Manganese Field, Northern Cape Province, South Africa. Scale: Picture size 5 cm.
© John Veevaert

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  Ericssonite   Orthoericssonite   Tephroite

Comments: Dark brown ericssonite, intergrown with orthoericssonite, with pink rhodonite, light brown diopside (var. schefferite) and gray tephroite.
Location: Langban, Varmland, Sweden. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

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  Johnbaumite   Tephroite

Comments: Violet crystalline massive johnbaumite with brown tephroite.
Location: Jacobsberg, Varmland, Sweden. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Tephroite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.4666:1:0.5862
Help on Cell Dimensions: Cell Dimensions: a = 4.76, b = 10.2, c = 5.98, Z = 4; V = 290.34 Den(Calc)= 4.62
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: P nma
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.56(1), 2.86(0.85), 3.61(0.85),
 

Physical Properties of Tephroite

Help on Cleavage: Cleavage: {010} Indistinct
Help on Color: Color: Gray, Olive green, Bluish green, Red, Reddish brown.
Help on Density: Density: 4.11 - 4.39, Average = 4.25
Help on Diaphaneity: Diaphaneity: Transparent to translucent
Help on Fracture: Fracture: Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.
Help on Habit: Habit: Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Help on Habit: Habit: Massive - Granular - Common texture observed in granite and other igneous rock.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Hardness: Hardness: 6.5 - Pyrite
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Vitreous - Greasy
Help on Magnetism: Magnetism: Nonmagnetic
Help on Streak: Streak: gray
 

Optical Properties of Tephroite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.054 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.13 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1743,KPDmeas= 0.1895,KC= 0.2003
Ncalc = 1.82 - 1.93
Help on Optical Data: Optical Data: Biaxial (+), a=1.759, b=1.797, g=1.86, bire=0.1010, 2V(Calc)=78, 2V(Meas)=60-70. Dispersion none.
Help on Pleochroism (x): Pleochroism (x): pale amber.
Help on Pleochroism (y): Pleochroism (y): orange yellow.
 

Calculated Properties of Tephroite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=4.04 gm/cc
note: Specific Gravity of Tephroite =4.25 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0066464499
Boson Index = 0.9933535501
Help on Photoelectric: Photoelectric: PETephroite = 14.67 barns/electron
U=PETephroite x rElectron Density= 59.28 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Tephroite is Not Radioactive
 

Tephroite Classification

Help on  Dana Class: Dana Class: 51.03.01.04 (51)Nesosilicate Insular SiO4 Groups Only
  (51.03)with all cations in octahedral [6] coordination
  (51.03.01)Olivine group
 
51.03.01.00 Olivine* (Mg,Fe)2SiO4 Pbnm 2/m 2/m 2/m
 
51.03.01.01 Fayalite Fe2SiO4 Pbnm 2/m 2/m 2/m
 
51.03.01.02 Forsterite Mg2SiO4 Pbnm 2/m 2/m 2/m
 
51.03.01.03 Liebenbergite (Ni,Mg)2SiO4 Pbnm 2/m 2/m 2/m
 
51.03.01.04 Tephroite Mn2SiO4 P nma 2/m 2/m 2/m
 
51.03.01.05 Laihunite FeFe2(SiO4)2 P 21/b 2/m
Help on  Strunz Class: Strunz Class: 09.AC.05 09 - SILICATES (Germanates)
  09.A - Nesosilicates
  09.AC -Nesosilicates without additional anions;
 
09.AC.05 Forsterite Mg2SiO4 Pbnm 2/m 2/m 2/m
 
09.AC.05 Glaucochroite CaMnSiO4 Pbnm 2/m 2/m 2/m
 
09.AC.05 Fayalite Fe2SiO4 Pbnm 2/m 2/m 2/m
 
09.AC.05 Olivine* (Mg,Fe)2SiO4 Pbnm 2/m 2/m 2/m
 
09.AC.05 Kirschsteinite CaFeSiO4 Pbmn 2/m 2/m 2/m
 
09.AC.05 Laihunite FeFe2(SiO4)2 P 21/b 2/m
 
09.AC.05 Liebenbergite (Ni,Mg)2SiO4 Pbnm 2/m 2/m 2/m
 
09.AC.05 Tephroite Mn2SiO4 P nma 2/m 2/m 2/m
 

Other Tephroite Information

Help on See Also: See Also: Links to other databases for Tephroite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - CalTech Mineral Spectroscopy
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - Franklin Minerals(Dunn)
8 - Franklin Minerals(Palache)
9 - GeoScienceWorld
10 - Google Images
11 - Google Scholar
12 - Handbook of Mineralogy (MinSocAm)
13 - Handbook of Mineralogy (UofA)
14 - MinDAT
15 - Mineral and Gemstone Kingdom
16 - Mineralienatlas (Deutsch)
17 - Online Mineral Museum
18 - QUT Mineral Atlas
19 - Ruff.Info
20 - Scandinavian mineral gallery
21 - University of Colorado - Mineral Structure Data
22 - WWW-MINCRYST

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

Tephroite

Mn2SiO4
Dana No: 51.03.01.04 Strunz No: 09.AC.05
Locality:

 

Notes:

 

 


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