Okayamalite Mineral Data

Okayamalite Mineral Data +

General Okayamalite Information

Chemical Formula:

Ca2B2SiO7

Composition:

Molecular Weight = 241.86 gm

Calcium 33.14 % Ca 46.37 % CaO

Silicon 11.61 % Si 24.84 % SiO₂

Boron 8.94 % B 28.78 % B₂O₃

Oxygen 46.31 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂B₂SiO₇

Environment:

The boron-dominant analogue of gehlenite. Skarn mineral probably formed by the desilication-dehydroxylation of datolite.

IMA Status:

Approved IMA 1998 (Dana # Added)

Locality:

The Fuka mine, Bicchu-cho, Okayama Prefecture, Japan. Link to MinDat.org Location Data.

Name Origin:

Named after it's locality.

Synonym:

ICSD 89739

IMA1997-002

Search for Okayamalite 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.

Okayamalite Crystallography

Axial Ratios:

a:c = 1:0.67664

Cell Dimensions:

a = 7.116, c = 4.815, Z = 2; V = 243.82 Den(Calc)= 3.29

Crystal System:

Tetragonal - ScalenohedralH-M Symbol (4 2m) Space Group: P 42₁m

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

By Intensity(I/I_o): 2.655(1), 2.862(0.56), 3.479(0.4),1.92(0.35), 1.644(0.2), 2.128(0.2), 2.23(0.15), 1.726(0.1), 2.25(0.1),

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

Giuli G , Bindi L , Bonazzi P , American Mineralogist , 85 (2000) p.1512-1515, Rietveld refinement of okayamalite, Ca2SiB2O7: Structural evidence for the, B/Si ordered distribution

Physical Properties of Okayamalite

Cleavage:

None

Color:

Creamy white.

Density:

3.3

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Hardness:

5.5 - Knife Blade

Luster:

Earthy (Dull)

Streak:

white

Optical Properties of Okayamalite

Gladstone-Dale:

CI meas= 0.016 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.013 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2082,KPDmeas= 0.2076,KC= 0.2109

Optical Data:

Uniaxial (-), e=1.67, w=1.7, bire=0.0300.

Calculated Properties of Okayamalite

Electron Density:

r_electron=3.26 gm/cc
note: r_Okayamalite=3.29 gm/cc.

Fermion Index

Fermion Index = 0.02388
Boson Index = 0.97612

Photoelectric:

PE_Okayamalite= 4.63 barns/electron
U=PE_Okayamalite x r_electron= 15.11 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Okayamalite is Not Radioactive

Okayamalite Classification

Dana Class:

55.4.1.4 (55)Sorosilicate Si2O7 Groups, Generally with No Additional Anions

(55.4)with cations in [8] and lower coordination

(55.4.1)Melilite group

55.4.1.1 Akermanite Ca2MgSi2O7 P 42₁m 4 2m

55.4.1.2 Gehlenite Ca2Al(AlSi)O7 P 42₁m 4 2m

55.4.1.3 Melilite (Ca,Na)2(Al,Mg,Fe)(Si,Al)2O7 P 42₁m 4 2m

55.4.1.4 Okayamalite ! Ca2B2SiO7 P 42₁m 4 2m

Strunz Class:

VIII/C.02-14 VIII - Silicates

VIII/C - Sorosilicates, with [Si2O7]6-, without anions unfamiliar to tetraheders

VIII/C.02 - Melilite group

VIII/C.02-10 Akermanite Ca2MgSi2O7 P 42₁m 4 2m

VIII/C.02-14 Okayamalite Ca2B2SiO7 P 42₁m 4 2m

VIII/C.02-15 Gehlenite Ca2Al(AlSi)O7 P 42₁m 4 2m

VIII/C.02-30 Gugiaite Ca2BeSi2O7 P 42₁m 4 2m

VIII/C.02-40 Hardystonite Ca2ZnSi2O7 P 42₁m 4 2m

VIII/C.02-50 Leucophanite (Na,Ca)2BeSi2(O,OH,F)7 P1 1

VIII/C.02-60 Jeffreyite (Ca,Na)2(Be,Al)Si2(O,OH)7 C 222₁ 2 2 2

VIII/C.02-70 Meliphanite (Ca,Na)2Be[(Si,Al)2O6(F,OH)] I 4 4

VIII/C.02-80 Barylite BaBe2Si2O7 Pn21a mm2

VIII/C.02-85 Clinobarylite! BaBe2Si2O7 Pmn2 2/m 2/m 2/m

VIII/C.02-90 Andremeyerite BaFe(Fe,Mn,Mg)Si2O7 P 2₁/c 2/m

Other Okayamalite Information

References:

NAME( MinRec) PHYS. PROP.(Eur. J. Min.,Vol.10,1998) OPTIC PROP.(MinRec)

See Also:

Links to other databases for Okayamalite :
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 - WWW-MINCRYST

Search for Okayamalite using:

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

Visit our Advertisers for Okayamalite :
AA Mineral Specimens
A-Rocks Auction
Adams Minerals
B and L Minerals
Dakota Matrix
Dan Weinrich Fine Minerals
Dan Weinrich Auctions
e-Rocks Auctions
Excalibur Minerals
Exceptional Minerals
Fabre Minerals
Greenside Minerals
John Betts Fine Minerals
Masons Minerals
Mineral News
Mineral of the Month Club
MineralsWeb Fine Minerals
Minernet.it
Rockshop.cz Kalat Fine Minerals
T G Fine Minerals
Wrights Rock Shop

Translate Okayamalite Mineral Data :

Ask about Okayamalite 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 Okayamalite Specimen Label here :

Okayamalite

Ca2B2SiO7
Dana No: 55.4.1.4 Strunz No: VIII/C.02-14
Locality:

Notes: