Oftedalite Mineral Data

[How the Club Works] [Memberships - Junior, Deluxe , and Platinum] [FAQ] [Past Minerals]
Join the Club - Junior, Deluxe and Platinum Memberships Available
High Quality Minerals Sent to Your Home or School Each Month
Mineral of the Month Club - An Inexpensive Way to Enjoy Minerals

General Oftedalite Information

Chemical Formula:

(Sc,Ca)2KBe3Si12O30

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

Empirical Formula:

Environment:

Occurs intergrown with Sc-rich milarite in the Heftetjern pegmatite. Milarite group

IMA Status:

Approved IMA 2004 (Dana # Added)

Locality:

Heftetjern pegmatite, about 4.3 km NW of Tørdal, Telemark county, southern Norway. Link to MinDat.org Location Data.

Name Origin:

Named for Ivar Oftedal (1894-1976), former Professor of Mineralogy at the Institute of Geology, University of Oslo, Norway.

Synonym:

IMA2003-045a

Search for Oftedalite Images

Images:

Image not yet available on Webmineral.com

Try searching images.google.com or Mindat Picture Gallary for mineral pictures. Caution: The images retrieved may not be appropriate.

Oftedalite Crystallography

Axial Ratios:

a:c = 1:1.38565

Cell Dimensions:

a = 10.097, c = 13.991, Z = 2; V = 1,235.28 Den(Calc)= 2.62

Crystal System:

Hexagonal - Dihexagonal DipyramidalH-M Symbol (6/m 2/m 2/m) Space Group: P 6/mmc

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 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),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Cooper M A , Hawthorne F C , Ball N A , Cerny P , Kristiansen R , The Canadian Mineralogist , 44 (2006) p.943-949, Oftedalite, (Sc,Ca,Mn2+)2 K (Be,Al)3 Si12 O30, a new member of the milarite, group from the Heftetjern pegmatite, Tordal, Norway: description and crystal, structure, Locality: Heftetjern pegmatite, Tordal, Norway

Physical Properties of Oftedalite

Cleavage:

{hk0} Poor

Color:

Grayish white.

Diaphaneity:

Transparent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Hexagonal - Six-sided crystal shape in cross-section or habit.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

6 - Orthoclase

Luster:

Vitreous (Glassy)

Streak:

colorless

Optical Properties of Oftedalite

Gladstone-Dale:

CI calc= 0.006 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2116,KC= 0.2129
Ncalc = 1.56

Optical Data:

Uniaxial (-), e=1.553, w=1.556, bire=0.0030.

Calculated Properties of Oftedalite

Electron Density:

Bulk Density (Electron Density)=2.59 gm/cc
note: Specific Gravity of Oftedalite =2.62 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_Oftedalite= 3.42 barns/electron
U=PE_Oftedalite x r_electron= 8.88 barns/cc.

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

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

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

References:

NAME( AmMin, v91, p1948) PHYS. PROP.(AmMin, v91, p1948) OPTIC PROP.(AmMin, v91, p1948)

See Also:

Links to other databases for Oftedalite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - Google Images
4 - Google Scholar
5 - MinDAT
6 - MinMax(Deutsch)
7 - MinMax(English)
8 - Mineralienatlas (Deutsch)
9 - QUT Mineral Atlas
10 - Ruff.Info

Search for Oftedalite using:

[ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Oftedalite :

AA Mineral Specimens

B & L Fine Minerals

Crystalarium.com

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

Dakota Matrix

Diamond Dan Publications

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

Wrights Rock Shop

Translate Oftedalite Mineral Data :

Ask about Oftedalite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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: