Tadzhikite-(Ce) Mineral Data

General Tadzhikite-(Ce) Information

Chemical Formula: Ca4(Ce,Y)2(Ti,Al,Fe+++,[ ])2[Si4B4O22](OH)2 Composition: Molecular Weight = 998.93 gm    Calcium   16.05 %  Ca   22.46 % CaO    Cerium    21.04 %  Ce   24.64 % Ce₂O₃    Yttrium    4.45 %  Y     5.65 % Y₂O₃    Titanium   2.88 %  Ti    4.80 % TiO₂    Aluminum   0.81 %  Al    1.53 % Al₂O₃    Iron       0.56 %  Fe    0.80 % Fe₂O₃    Silicon   11.25 %  Si   24.06 % SiO₂    Boron      4.33 %  B    13.94 % B₂O₃    Hydrogen   0.20 %  H     1.80 % H₂O    Oxygen    38.44 %  O             ______        ______              100.00 %       99.68 % = TOTAL OXIDE Empirical Formula: Ca₄Ce_1.5Y_0.5Ti_0.6Al_0.3Fe³⁺_0.1B₄Si₄O₂₂(OH)₂ IMA Status: Approved IMA 1987 Locality: In the Dara-i-Pioz massif, Alai Range, Tien Shan, Tajikistan (Tadzhikistan). Link to MinDat.org Location Data. Name Origin: Named for the locality and its cerium content. Name Pronunciation: Tadzhikite-(Ce) + Pronunciation Synonym: ICSD 20528   IMA2000-F   PDF 24-137   Tadzhikite  

Tadzhikite-(Ce) Image

Images:

Tadzhikite-(Ce) Comments: Brown crystal of tadzhikite-(Ce) with baratovite, polylithionite and zektzerite in matrix. Location: Dara-I-Pioz, Tajikistan. Scale: Specimen Size 1.5x2 cm. © Diederik Visser

Tadzhikite-(Ce) Crystallography

Axial Ratios: a:b:c =3.8067:1:2.2059 Cell Dimensions: a = 17.93, b = 4.71, c = 10.39, Z = 2; beta = 100.75° V = 862.04 Den(Calc)= 3.85 Crystal System: Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2/a X Ray Diffraction: By Intensity(I/I_o): 2.65(1), 1.913(0.55), 4.97(0.3), Crystal Structure:

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Hawthorne F C , Cooper M A , Taylor M C , The Canadian Mineralogist , 36 (1998) p.817-822, Refinement of the crystal structure of tadzhikite, Locality: Dara-i-Pioz, Tadzhikistan

 

Physical Properties of Tadzhikite-(Ce)

Cleavage: {010} Distinct Color: Gray brown, Reddish brown. Density: 3.73 - 3.86, Average = 3.79 Diaphaneity: Translucent Hardness: 6 - Orthoclase Luster: Vitreous (Glassy) Streak: white  

Optical Properties of Tadzhikite-(Ce)

Gladstone-Dale: CI meas= 0.011 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.025 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1978,KPDmeas= 0.2007,KC= 0.2029
Ncalc = 1.76 - 1.78 Optical Data: Biaxial (+/-), a=1.75-1.761, g=1.763-1.772, bire=0.0110-0.0130, 2V(Meas)=80-92.  

Calculated Properties of Tadzhikite-(Ce)

Electron Density: Bulk Density (Electron Density)=3.62 gm/cc
note: Specific Gravity of Tadzhikite-(Ce) =3.80 gm/cc.
Fermion Index: Fermion Index = 0.01
Boson Index = 0.99 Photoelectric: PE_{Tadzhikite-(Ce)} = 110.60 barns/electron
U=PE_{Tadzhikite-(Ce)} x r_electron= 400.17 barns/cc.
Radioactivity:

GRapi = 21,397.15 (Gamma Ray American Petroleum Institute Units)
Concentration of Tadzhikite-(Ce) per GRapi unit = 46.74 (PPM)

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

Estimated Radioactivity from Tadzhikite-(Ce) - weak

Specimen Size Weight/Volume (Sphere) *	Calculated Activity Becquerels (Bq)	Calculated Activity Curies (Ci)	Estimated Activity GR(api)	Estimated Exposure (mRem**)/hr If Held in Hand For One Hour
1000 gm / 7.95 cm	471,292	1.27E-05	21,397.15	7.03
100 gm / 3.69 cm	47,129	1.27E-06	2,139.72	0.70
10 gm / 1.71 cm	4,713	1.27E-07	213.97	0.07
1 gm / 7.95 mm	471	1.27E-08	21.40	0.01
0.1 gm / 3.69 mm	47	1.27E-09	2.14	0.00
0.01 gm / 1.71 mm	5	1.27E-10	0.21	0.00
0.001 gm / 0.80 mm	0	1.27E-11	0.02	0.00

Weight of pure Tadzhikite-(Ce) in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.80 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 ( 1.05 % Th) From Sum REE Elements (21.04 % REE)

 

Tadzhikite-(Ce) Classification

Dana Class: 54.02.02.03 (54)Nesosilicate Borosilicates and Some Beryllosilicates   (54.02)with B in [4] coordination   (54.02.02)Hellandite group  

54.02.02.01 Hellandite-(Y) (Ca,REE)4(Y,Ce)2(Al,[])2[Si4B4O22](OH)2 P 2/a 2/m

 

54.02.02.02 Tadzhikite-(Y)! Ca4(Y,Ce)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

 

54.02.02.03 Tadzhikite-(Ce) Ca4(Ce,Y)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

 

54.02.02.04 Hellandite-(Ce)! (Ca3REE)4Ce2Al[]2[Si4B4O22](OH)2 P 2/a 2/m

 

54.02.02.05 Mottanaite-(Ce)! Ca4(Ce,Ca)2AlBe2[Si4B4O22]O2 P 2/a 2/m

 

54.02.02.06 Ciprianiite! Ca4[(Th,U)(REE)]2(Al,[])2[Si4B4O22](OH,F)2 P 2/a 2/m

 

54.02.02.07 Piergorite-(Ce)! Ca8Ce2(Al0.5Fe0.5)([],Li,Be)2Si6B8O36(OH,F)2 P 2/a 2/m

Strunz Class: 09.DK.20 09 - SILICATES (Germanates)   09.D - Inosilicates* Structural terminology according to Liebau (1985)   09.DK -Inosilicates with 5-periodic single chains  

09.DK.20 Hellandite-(Y) (Ca,REE)4(Y,Ce)2(Al,[])2[Si4B4O22](OH)2 P 2/a 2/m

 

09.DK.20 Tadzhikite-(Ce) Ca4(Ce,Y)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

 

09.DK.20 Tadzhikite-(Y)! Ca4(Y,Ce)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

 

09.DK.20 Ciprianiite! Ca4[(Th,U)(REE)]2(Al,[])2[Si4B4O22](OH,F)2 P 2/a 2/m

 

09.DK.20 Hellandite-(Ce)! (Ca3REE)4Ce2Al[]2[Si4B4O22](OH)2 P 2/a 2/m

 

09.DK.20 Mottanaite-(Ce)! Ca4(Ce,Ca)2AlBe2[Si4B4O22]O2 P 2/a 2/m

 

Other Tadzhikite-(Ce) Information

References: PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990) See Also: Links to other databases for Tadzhikite-(Ce) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info
12 - WWW-MINCRYST
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