Mineralogy Database

Oftedalite Mineral Data

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General Oftedalite Information

Help on Chemical  Formula: Chemical Formula: (Sc,Ca)2KBe3Si12O30
Help on Composition: Composition: Molecular Weight = 973.03 gm
   Potassium   3.94 %  K     4.74 % K2O
   Calcium     3.25 %  Ca    4.55 % CaO
   Yttrium     0.27 %  Y     0.35 % Y2O3
   Scandium    4.44 %  Sc    6.80 % Sc2O3
   Manganese   1.02 %  Mn    1.31 % MnO
   Beryllium   2.70 %  Be    7.48 % BeO
   Aluminum    0.25 %  Al    0.47 % Al2O3
   Iron        0.23 %  Fe    0.30 % FeO
   Silicon    34.58 %  Si   73.98 % SiO2
   Oxygen     49.33 %  O
             ______        ______ 
             100.00 %       99.98 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula:
Help on Environment: Environment: Occurs intergrown with Sc-rich milarite in the Heftetjern pegmatite. Milarite group
Help on IMA Status: IMA Status: Approved IMA 2004 (Dana # Added)
Help on Locality: Locality: Heftetjern pegmatite, about 4.3 km NW of T�rdal, Telemark county, southern Norway. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Ivar Oftedal (1894-1976), former Professor of Mineralogy at the Institute of Geology, University of Oslo, Norway.
Help on Synonym: Synonym: IMA2003-045a
 

Oftedalite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:1.38565
Help on Cell Dimensions: Cell Dimensions: a = 10.097, c = 13.991, Z = 2; V = 1,235.28 Den(Calc)= 2.62
Help on Crystal System: Crystal System: Hexagonal - Dihexagonal Dipyramidal H-M Symbol (6/m 2/m 2/m) Space Group: P 6/mmc
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.229(1)(104), 2.88(0.8)(114), 4.097(0.7)(112),3.504(0.5)(004), 5.044(0.5)(110), 7.012(0.4)(002), 1.836(0.4)(412), 1.995(0.3)(314), 2.735(0.3)(204),
 

Physical Properties of Oftedalite

Help on Cleavage: Cleavage: {hk0} Poor
Help on Color: Color: Grayish white.
Help on Diaphaneity: Diaphaneity: Transparent
Help on Fracture: Fracture: Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.
Help on Habit: Habit: Hexagonal - Six-sided crystal shape in cross-section or habit.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Hardness: Hardness: 6 - Orthoclase
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: colorless
 

Optical Properties of Oftedalite

Help on Gladstone-Dale: Gladstone-Dale: CI calc= 0.006 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2116,KC= 0.2129
Ncalc = 1.56
Help on Optical Data: Optical Data: Uniaxial (-), e=1.553, w=1.556, bire=0.0030.
 

Calculated Properties of Oftedalite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.59 gm/cc
note: Specific Gravity of Oftedalite =2.62 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.04
Boson Index = 0.96
Help on Photoelectric: Photoelectric: PEOftedalite = 3.42 barns/electron
U=PEOftedalite x relectron= 8.88 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 56.26 (Gamma Ray American Petroleum Institute Units)
Concentration of Oftedalite per GRapi unit = 1.78 (%)

Estimated Radioactivity from Oftedalite - barely detectable

 

Oftedalite Classification

Help on  Dana Class: Dana Class: 63.02.01a.19 (63)Cyclosilicate Condensed Rings
  (63.02)6-membered rings
  (63.02.01a)Milarite - Osumilite group (Milarite - Osumilite subgroup)
 
63.02.01a.01 Brannockite KSn2Li3Si12O30 P 6/mcc 6/m 2/m 2/m
 
63.02.01a.02 Chayesite K(Mg,Fe)4Fe(Si12O30) P 6/mcc 6/m 2/m 2/m
 
63.02.01a.03 Darapiosite KNa2Zr[Li(Mn,Zr)2Si12O30] P 6/mcc 6/m 2/m 2/m
 
63.02.01a.04 Eifelite KNa3Mg4Si12O30 P 6/mcc 6/m 2/m 2/m
 
63.02.01a.05 Merrihueite (K,Na)2(Fe,Mg)5Si12O30 P 6/mcc 6/m 2/m 2/m
 
63.02.01a.06 Osumilite-(Fe) (K,Na)(Fe,Mg)2(Al,Fe)3(Si,Al)12O30 P 6/mcc 6/m 2/m 2/m
 
63.02.01a.07 Osumilite-(Mg) (K,Na)(Mg,Fe)2(Al,Fe)3(Si,Al)12O30 P 6/mcc 6/m 2/m 2/m
 
63.02.01a.08 Poudretteite KNa2B3Si12O30 P 6/mcc 6/m 2/m 2/m
 
63.02.01a.09 Sugilite KNa2(Fe,Mn,Al)2Li3Si12O30 P 6/mcc 6/m 2/m 2/m
 
63.02.01a.10 Yagiite (Na,K)3Mg4(Al,Mg)6(Si,Al)24O60 P 6/mmc 6/m 2/m 2/m
 
63.02.01a.11 Dusmatovite K(K,Na,[])(Mn,Y,Zr)2(Zn,Li)3Si12O30 P 6/mcc 6/m 2/m 2/m
 
63.02.01a.12 Milarite K2Ca4Al2Be4Si24O60•(H2O) P 6/mcc 6/m 2/m 2/m
 
63.02.01a.13 Sogdianite (K,Na)2(Li,Fe,Al)3ZrSi12O30 P 6/mmm 6/m 2/m 2/m
 
63.02.01a.14 Roedderite (Na,K)2(Mg,Fe)5Si12O30 P 63/mmc 6/m 2/m 2/m
 
63.02.01a.15 Berezanskite! KLi3Ti2Si12O30 P 6/mcc 6/m 2/m 2/m
 
63.02.01a.16 Shibkovite! K(Ca,Mn,Na)2(K2-x,[]x)2ZnSi12O30(x~0.8) P 6/mcc 6/m 2/m 2/m
 
63.02.01a.17 Trattnerite! (Fe,Mg)2(Mg,Fe)3(Si12O30) P 6/mcc 6/m 2/m 2/m
 
63.02.01a.18 Almarudite! K([],Na)2(Mn,Fe,Mg)2(Be,Al)3[Si12O30] P 6/mcc 6/m 2/m 2/m
 
63.02.01a.19 Oftedalite! (Sc,Ca)2KBe3Si12O30 P 6/mmc 6/m 2/m 2/m
 
63.02.01a.20 Klochite ([]1Na1)KFe2Zn3[Si12O30] P 6/mcc 6/m 2/m 2/m
 
63.02.01a.21 Friedrichbeckeite! K([],Na)Mg2(Be2Mg)Si12O30 P 6/mcc 6/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 09.CM.05 09 - SILICATES (Germanates)
  09.C - Cyclosilicates
  09.CM -[Si6O18]12- 6-membered double rings (sechser-Doppelringe)
 
09.CM.05 Brannockite KSn2Li3Si12O30 P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Armenite BaCa2Al6Si9O30•2(H2O) Pnc2 mm2
 
09.CM.05 Berezanskite! KLi3Ti2Si12O30 P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Dusmatovite K(K,Na,[])(Mn,Y,Zr)2(Zn,Li)3Si12O30 P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Chayesite K(Mg,Fe)4Fe(Si12O30) P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Shibkovite! K(Ca,Mn,Na)2(K2-x,[]x)2ZnSi12O30(x~0.8) P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Eifelite KNa3Mg4Si12O30 P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Darapiosite KNa2Zr[Li(Mn,Zr)2Si12O30] P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Merrihueite (K,Na)2(Fe,Mg)5Si12O30 P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Roedderite (Na,K)2(Mg,Fe)5Si12O30 P 63/mmc 6/m 2/m 2/m
 
09.CM.05 Milarite K2Ca4Al2Be4Si24O60•(H2O) P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Osumilite-(Fe) (K,Na)(Fe,Mg)2(Al,Fe)3(Si,Al)12O30 P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Osumilite-(Mg) (K,Na)(Mg,Fe)2(Al,Fe)3(Si,Al)12O30 P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Poudretteite KNa2B3Si12O30 P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Sugilite KNa2(Fe,Mn,Al)2Li3Si12O30 P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Sogdianite (K,Na)2(Li,Fe,Al)3ZrSi12O30 P 6/mmm 6/m 2/m 2/m
 
09.CM.05 Oftedalite! (Sc,Ca)2KBe3Si12O30 P 6/mmc 6/m 2/m 2/m
 
09.CM.05 Yagiite (Na,K)3Mg4(Al,Mg)6(Si,Al)24O60 P 6/mmc 6/m 2/m 2/m
 
09.CM.05 Trattnerite! (Fe,Mg)2(Mg,Fe)3(Si12O30) P 6/mcc 6/m 2/m 2/m
 
09.CM.05 Almarudite! K([],Na)2(Mn,Fe,Mg)2(Be,Al)3[Si12O30] P 6/mcc 6/m 2/m 2/m
 

Other Oftedalite Information

Help on References: References: NAME( AmMin, v91, p1948) PHYS. PROP.(AmMin, v91, p1948) OPTIC PROP.(AmMin, v91, p1948)
Help on See Also: See Also: Links to other databases for Oftedalite :
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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Print or Cut-and-Paste your Oftedalite Specimen Label here :

Oftedalite

(Sc,Ca)2KBe3Si12O30
Dana No: 63.02.01a.19 Strunz No: 09.CM.05
Locality:

 

Notes:

 

 
   
 


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