Mineralogy Database

Thortveitite Mineral Data

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General Thortveitite Information

Help on Chemical  Formula: Chemical Formula: (Sc,Y)2Si2O7
Help on Composition: Composition: Molecular Weight = 280.05 gm
   Yttrium   15.87 %  Y    20.16 % Y2O3
   Scandium  24.08 %  Sc   36.93 % Sc2O3
   Silicon   20.06 %  Si   42.91 % SiO2
   Oxygen    39.99 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Sc1.5Y0.5Si2O7
Help on Environment: Environment: Granitic pegmatite rocks.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1911
Help on Locality: Locality: Iveland, Setesdal, Norway. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after the Norwegian engineer, O. Thortveit.
Help on Name Pronunciation: Name Pronunciation: Thortveitite + Pronunciation Say THORTVEITITE
Help on Synonym: Synonym: ICSD 75925
  PDF 20-1037

Thortveitite Image

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Comments: Small white prismatic crystals of thortveitite on matrix.
Location: A4 highway tunnel, Thiemendorf, Königshain, Oberlausitz, Saxony, Germany. Scale: Picture size 1.7 mm.
© Thomas Witzke / Abraxas-Verlag

Thortveitite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.7706:1:0.5493
Help on Cell Dimensions: Cell Dimensions: a = 6.587, b = 8.547, c = 4.695, Z = 2; beta = 102.65° V = 257.91 Den(Calc)= 3.61
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.11(1), 3.13(1), 2.93(0.45),

Physical Properties of Thortveitite

Help on Cleavage: Cleavage: {100} Perfect
Help on Color: Color: Brown, Grayish black, Black, Grayish green.
Help on Density: Density: 3.5
Help on Diaphaneity: Diaphaneity: Translucent to opaque
Help on Fracture: Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Help on Habit: Habit: Crystalline - Fine - Occurs as well-formed fine sized crystals.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Habit: Habit: Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Help on Hardness: Hardness: 6.5 - Pyrite
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Vitreous - Adamantine
Help on Streak: Streak: gray

Optical Properties of Thortveitite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.028 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.003 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2177,KPDmeas= 0.2246,KC= 0.2184
Ncalc = 1.76 - 1.79
Help on Optical Data: Optical Data: Biaxial (-), a=1.756, b=1.793, g=1.809, bire=0.0530, 2V(Calc)=64, 2V(Meas)=65.
Help on Pleochroism (x): Pleochroism (x): deep green.
Help on Pleochroism (y): Pleochroism (y): brownish yellow.
Help on Pleochroism (z): Pleochroism (z): brownish yellow.

Calculated Properties of Thortveitite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.48 gm/cc
note: Specific Gravity of Thortveitite =3.61 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0095586837
Boson Index = 0.9904413163
Help on Photoelectric: Photoelectric: PEThortveitite = 23.53 barns/electron
U=PEThortveitite x rElectron Density= 81.90 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Thortveitite is Not Radioactive

Thortveitite Classification

Help on  Dana Class: Dana Class: 55.02.01a.04 (55)Sorosilicate Si2O7 Groups, Generally with No Additional Anions
  (55.02)with cations in [6] coordination
  (55.02.01a)Thortveitite group
55.02.01a.01 Gittinsite CaZrSi2O7 C 2/m 2/m
55.02.01a.02 Keiviite-(Y) (Y,Yb)2Si2O7 C 2/m 2/m
55.02.01a.03 Keiviite-(Yb) (Yb,Y)2Si2O7 C 2/m 2/m
55.02.01a.04 Thortveitite (Sc,Y)2Si2O7 C 2/m 2/m
Help on  Strunz Class: Strunz Class: 09.BC.05 09 - SILICATES (Germanates)
  09.B - Sorosilicates
  09.BC -Si2O7 groups, without non-tetrahedral anions;
09.BC.05 Keiviite-(Y) (Y,Yb)2Si2O7 C 2/m 2/m
09.BC.05 Gittinsite CaZrSi2O7 C 2/m 2/m
09.BC.05 Keiviite-(Yb) (Yb,Y)2Si2O7 C 2/m 2/m
09.BC.05 Thortveitite (Sc,Y)2Si2O7 C 2/m 2/m
09.BC.05 Yttrialite-(Y) (Y,Th)2Si2O7 P 21/m 2/m

Other Thortveitite Information

Help on References: References: NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)
Help on See Also: See Also: Links to other databases for Thortveitite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Dunn)
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info

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Dana No: 55.02.01a.04 Strunz No: 09.BC.05





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