Dissakisite-(Ce) Mineral Data

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General Dissakisite-(Ce) Information

Chemical Formula:

Ca(Ce,REE)(Mg,Fe++)(Al,Fe+++)2Si3O12(OH)

Composition:

Molecular Weight = 599.36 gm

Calcium 6.69 % Ca 9.36 % CaO

Cerium 10.52 % Ce 12.32 % Ce₂O₃

La,Ce,Pr,Nd,Sm, 15.62 % RE 18.22 % REE₂O₃

Magnesium 4.46 % Mg 7.40 % MgO

Aluminum 5.40 % Al 10.21 % Al₂O₃

Iron 8.39 % Fe 5.39 % FeO / 5.99 % Fe₂O₃

Silicon 14.06 % Si 30.07 % SiO₂

Hydrogen 0.17 % H 1.50 % H₂O

Oxygen 34.70 % O

______ ______

100.00 % 100.47 % = TOTAL OXIDE

Empirical Formula:

CaCe_0.45REE_0.65Mg_1.1Fe²⁺_0.45Al_1.2Fe³⁺_0.45Si₃O₁₂(OH)

Environment:

Formed in marble under amphibolite-facies metamorphism (600 deg C and 7 Kbar).

IMA Status:

Approved IMA 1991- Dana Number Modified from 58.2.1a.5

Locality:

On the Balchen Mountain, Sor Rondane Mountains, east Antarctica. Link to MinDat.org Location Data.

Name Origin:

From the Greek for "twice over," for a magnesium analog of allanite being described twice.

Synonym:

ICSD 75920

IMA1990-004

PDF 47-1788

Dissakisite-(Ce) Image

Images:

Click Here for Larger Dissakisite-(Ce) Image

Dissakisite-(Ce) Dolomite

Comments: Small, prisimatic, acicular crystals of tan-colored dissakisite-(Ce) scatterd on white crystalline dolomite.
Location: Trimouns mine, Luzenac, Ariège France. Scale: Picture size 5 cm.
© Fabre Minerals

Dissakisite-(Ce) Crystallography

Axial Ratios:

a:b:c =1.5642:1:1.7789

Cell Dimensions:

a = 8.916, b = 5.7, c = 10.14, Z = 2; beta = 114.72° V = 468.10 Den(Calc)= 4.25

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/m

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

By Intensity(I/I_o): 2.698(1), 2.91(0.9), 2.622(0.6),

Crystal Structure:

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Rouse R C , Peacor D R , The Canadian Mineralogist , 31 (1993) p.153-157, The crystal structure of dissakisite-(Ce),the, Mg analogue of allanite-(Ce), Locality: Balchen Mountain, East Antartica

Physical Properties of Dissakisite-(Ce)

Cleavage:

{001} Good

Color:

Yellow brown, Reddish brown.

Density:

3.75

Diaphaneity:

Transparent

Habit:

Anhedral Grains - Granular minerals without the expression of crystal shapes

Hardness:

6.5-7 - Pyrite-Quartz

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Dissakisite-(Ce)

Gladstone-Dale:

CI meas= -0.025 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.096 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1752,KPDmeas= 0.1986,KC= 0.1937
Ncalc = 1.73 - 1.82

Optical Data:

Biaxial (+), a=1.735, b=1.741, g=1.758, bire=0.0230, 2V(Calc)=62, 2V(Meas)=64.2. Dispersion r < v medium.

Pleochroism (x):

pale brown.

Pleochroism (y):

light yellow brown.

Pleochroism (z):

light yellow brown.

Calculated Properties of Dissakisite-(Ce)

Electron Density:

Bulk Density (Electron Density)=3.57 gm/cc
note: Specific Gravity of Dissakisite-(Ce) =3.75 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_{Dissakisite-(Ce)}= 148.37 barns/electron
U=PE_{Dissakisite-(Ce)} x r_electron= 529.05 barns/cc.

Radioactivity:

GRapi = 26,565.28 (Gamma Ray American Petroleum Institute Units)
Concentration of Dissakisite-(Ce) per GRapi unit = 37.64 (PPM)

Dissakisite-(Ce) is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.

**Estimated Radioactivity from Dissakisite-(Ce)** - weak
Specimen Size Weight/Volume (Sphere) *	Calculated Activity Bequerols (Bq)	Calculated Activity Curies (Ci)	Estimated Activity GR(api)	Estimated Exposure (mRem**)/hr If Held in Hand For One Hour
1000 gm / 7.99 cm	586,711	1.59E-05	26,565.28	8.73
100 gm / 3.71 cm	58,671	1.59E-06	2,656.53	0.87
10 gm / 1.72 cm	5,867	1.59E-07	265.65	0.09
1 gm / 7.99 mm	587	1.59E-08	26.57	0.01
0.1 gm / 3.71 mm	59	1.59E-09	2.66	0.00
0.01 gm / 1.72 mm	6	1.59E-10	0.27	0.00
0.001 gm / 0.80 mm	1	1.59E-11	0.03	0.00

Weight of pure Dissakisite-(Ce) in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.75 gm/cc.*
Goverment Estimate of Average Annual Exposure ( 360 mRem) **
Note: 10 microsieverts/hr = 1 mRem/hr **
Max Permissable Adult Dose 50,000 mRem/yr (hands), 15,000 mRem/yr (eyes)
Lethal Dose LD(50) Exposure 400,000 to 500,000 mRem
Estimated Thorium Activity ( 1.31 % Th) From Sum REE Elements (26.14 % REE)

Dissakisite-(Ce) Classification

Dana Class:

58.02.01c.04 (58)Sorosilicate Insular, Mixed, Single, and Larger Tetrahedral Groups

(58.02)with cations in [6] and higher coordination; single and double groups (n=1,2)

(58.02.01c)Epidote group (Allanite subgroup)

58.02.01c.01 Allanite-(Ce) (Ce,Ca,Y)2(Al,Fe)3(SiO4)3(OH) P 2₁/m 2/m

58.02.01c.02 Allanite-(La)! Ca(REE,Ca)Al2(Fe,Fe)(SiO4)(Si2O7)O(OH) P 2₁/m 2/m

58.02.01c.03 Allanite-(Y) (Y,Ce,Ca)2(Al,Fe)3(SiO4)3(OH) P 2₁/m 2/m

58.02.01c.04 Dissakisite-(Ce) Ca(Ce,REE)(Mg,Fe)(Al,Fe)2Si3O12(OH) P 2₁/m 2/m

58.02.01c.05 Dissakisite-(La)! (Ca,Fe,Th,La)(La,REE,Ca)(Al,Cr,Ti)2(Mg,Fe,Al)Si3O12(OH,F)withLa>Ce P 2₁/m 2/m

58.02.01c.06 Manganiandrosite-(La)! (Mn,Ca)(La,Ce,Ca,Nd)AlMnMn(SiO4)(Si2O7)O(OH) P 2₁/m 2/m

58.02.01c.07 Ferriallanite-(Ce)! CaCe(Fe,Fe,Al)3[SiO4][Si2O7]O(OH) P 2₁/m 2/m

58.02.01c.08 Vastmanlandite-(Ce)! (Ce,La)3CaAl2Mg2[Si2O7][SiO4]3F(OH)2 P 2₁/m 2/m

58.02.01c.09 Manganiandrosite-(Ce)! (Mn,Ca)(Ce,REE)AlMnMn(Si2O7)(SiO4)O(OH) P 2₁/m 2/m

58.02.01c.10 Vanadoandrosite-(Ce)! (Mn,Ca)(REE)VAlMn(Si2O7)(SiO4)O(OH) P 2₁/m 2/m

Strunz Class:

09.BG.05b 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BG -Sorosilicates with mixed SiO4 and Si2O7 groups;

09.BG.05b Allanite-(La)! Ca(REE,Ca)Al2(Fe,Fe)(SiO4)(Si2O7)O(OH) P 2₁/m 2/m

09.BG.05b Allanite-(Y) (Y,Ce,Ca)2(Al,Fe)3(SiO4)3(OH) P 2₁/m 2/m

09.BG.05b Allanite-(Ce) (Ce,Ca,Y)2(Al,Fe)3(SiO4)3(OH) P 2₁/m 2/m

09.BG.05b Manganiandrosite-(La)! (Mn,Ca)(La,Ce,Ca,Nd)AlMnMn(SiO4)(Si2O7)O(OH) P 2₁/m 2/m

09.BG.05b Dissakisite-(Ce) Ca(Ce,REE)(Mg,Fe)(Al,Fe)2Si3O12(OH) P 2₁/m 2/m

09.BG.05b Manganiandrosite-(Ce)! (Mn,Ca)(Ce,REE)AlMnMn(Si2O7)(SiO4)O(OH) P 2₁/m 2/m

09.BG.05b Vanadoandrosite-(Ce)! (Mn,Ca)(REE)VAlMn(Si2O7)(SiO4)O(OH) P 2₁/m 2/m

09.BG.05b Dissakisite-(La)! (Ca,Fe,Th,La)(La,REE,Ca)(Al,Cr,Ti)2(Mg,Fe,Al)Si3O12(OH,F)withLa>Ce P 2₁/m 2/m

09.BG.05b Ferriallanite-(Ce)! CaCe(Fe,Fe,Al)3[SiO4][Si2O7]O(OH) P 2₁/m 2/m

09.BG.05b Uedaite-(Ce)! MnCeAl2Fe(Si2O7)(SiO4)O(OH) P 2₁/m 2/m

Other Dissakisite-(Ce) Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Am.Min.,Vol.76,p1990-1997,1991) OPTIC PROP.(AntBidBlaNic2)

See Also:

Links to other databases for Dissakisite-(Ce) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info
13 - WWW-MINCRYST

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Dissakisite-(Ce)

Ca(Ce,REE)(Mg,Fe++)(Al,Fe+++)2Si3O12(OH)
Dana No: 58.02.01c.04 Strunz No: 09.BG.05b
Locality:

Notes: