Chevkinite-(Ce) Mineral Data
General Chevkinite-(Ce) Information
Chemical Formula:
(Ce,La,Ca,Th)4(Fe++,Mg)2(Ti,Fe+++)3Si4O22
Composition:
Molecular Weight = 1,205.27 gm
Calcium 2.66 % Ca 3.72 % CaO
Lanthanum 16.13 % La 18.92 % La2 O3
Cerium 19.76 % Ce 23.15 % Ce2 O3
Thorium 1.93 % Th 2.19 % ThO2
Magnesium 0.40 % Mg 0.67 % MgO
Titanium 9.93 % Ti 16.57 % TiO2
Iron 10.66 % Fe 10.73 % FeO / 3.31 % Fe2 O3
Silicon 9.32 % Si 19.94 % SiO2
Oxygen 29.20 % O
______ ______
100.00 % 99.20 % = TOTAL OXIDE
Empirical Formula:
Ce1.7 La1.4 Ca0.8 Th0.1 Fe2+ 1.8 Mg0.2 Ti2.5 Fe3+ 0.5 Si4 O22
Environment:
Secondary mineral in titanium and cerium bearing rocks and as an accessory mineral in some granites.
IMA Status:
Valid Species (Pre-IMA) 1839
Locality:
Miask in the Ilmen Mountains, Russia. Link to MinDat.org Location Data.
Name Origin:
Named for General Konstatin Vladimirovich Tschevkin [Chevkin] (1802-1875), Chief o f Staff of the Russian Mining Engineers Corps.
Name Pronunciation:
Chevkinite-(Ce) + Pronunciation
Synonym:
Tscheffkinite
Chevkinite-(Ce) Image
Images:
Chevkinite-(Ce)
Comments: Dark brown crystal of chevkinite-(Ce).
Location: Miass, Central Ural Mountains, Russia.
Scale: 3 cm.
© Dave Barthelmy
Chevkinite-(Ce) Crystallography
Axial Ratios:
a:b:c =2.3298:1:1.9261
Cell Dimensions:
a = 13.56, b = 5.82, c = 11.21, Z = 2; beta = 100.75° V = 869.16 Den(Calc)= 4.61
Crystal System:
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m
X Ray Diffraction:
By Intensity(I/Io ): 2.71(1), 3.14(1), 3.17(1),
Physical Properties of Chevkinite-(Ce)
Cleavage:
None
Color:
Brownish black, Dark red.
Density:
4.5
Diaphaneity:
Translucent to subtranslucent to opaque
Fracture:
Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.
Habit:
Acicular - Occurs as needle-like crystals.
Habit:
Massive - Uniformly indistinguishable crystals forming large masses.
Habit:
Metamict - Mineral originally crystalline, now amorphous due to radiation damage.
Hardness:
5-5.5 - Apatite-Knife Blade
Luminescence:
Non-fluorescent.
Luster:
Earthy (Dull)
Streak:
black
Optical Properties of Chevkinite-(Ce)
Gladstone-Dale:
CI meas = -0.066 (Fair) - where the CI = (1-KPDmeas /KC ) CI calc = -0.04 (Good) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.2198,KPDmeas = 0.2252,KC = 0.2113 Ncalc = 1.95 - 1.97
Optical Data:
Biaxial (-), a=1.967-1.973, b=2.02, g=2.05, bire=0.0770-0.0830
Pleochroism (x):
nearly colorless.
Pleochroism (y):
pale reddish brown.
Pleochroism (z):
dark reddish brown.
Calculated Properties of Chevkinite-(Ce)
Electron Density:
Bulk Density (Electron Density)=4.23 gm/cc note: Specific Gravity of Chevkinite-(Ce) =4.61 gm/cc.
Fermion Index:
Fermion Index = 0.02 Boson Index = 0.98
Photoelectric:
PEChevkinite-(Ce) = 225.16 barns/electronU=PEChevkinite-(Ce) x r electron = 951.82 barns/cc.
Radioactivity:
GRapi = 37,661.04 (Gamma Ray American Petroleum Institute Units)
Concentration of Chevkinite-(Ce) per GRapi unit = 26.55 (PPM)
Chevkinite-(Ce) is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.
Estimated Maximum U.S. Postal Shipping Size
(10 mRem/hr limit, Unshielded 10 cm box)
807.64 ±201.91 grams of pure Chevkinite-(Ce) .
Estimated Radioactivity from Chevkinite-(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 / 7.45 cm
862,490
2.33E-05
37,661.04
12.38
100 gm / 3.46 cm
86,249
2.33E-06
3,766.10
1.24
10 gm / 1.61 cm
8,625
2.33E-07
376.61
0.12
1 gm / 7.45 mm
862
2.33E-08
37.66
0.01
0.1 gm / 3.46 mm
86
2.33E-09
3.77
0.00
0.01 gm / 1.61 mm
9
2.33E-10
0.38
0.00
0.001 gm / 0.75 mm
1
2.33E-11
0.04
0.00
Weight of pure Chevkinite-(Ce) in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.61 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
Chevkinite-(Ce) Classification
Dana Class:
56.02.08.01 (56) Sorosilicate Si2O7 Groups and O, OH, F. and H2O
(56.02) with cations in [4] and/or >[4] coordination
(56.02.08) Perierite - Chevkinite group
56.02.08.01 Chevkinite-(Ce) (Ce,La,Ca,Th)4(Fe,Mg)2(Ti,Fe)3Si4O22 C 2/m 2/m
56.02.08.02 Strontiochevkinite (Sr,REE)4Fe(Ti,Zr)2Ti2Si4O22 C 2/a 2/m
56.02.08.03 Perrierite-(Ce) (Ce,La,Ca)4(Fe,Mg)2(Ti,Fe)3Si4O22 C 21/a 2/m
56.02.08.04 Orthochevkinite * (Ce,La,Ca,Na,Th)4(Fe,Mg)2(Ti,Fe)3Si4O22 Unk Ortho
56.02.08.05 Rengeite ! Sr4ZrTi4Si4O22 P 21 /a 2/m
56.02.08.06 Matsubaraite ! Sr4TiTi4Si4O22 P 21 /a 2/m
56.02.08.07 Polyakovite-(Ce) ! (Ce,La,Nd,Pr,Ca)4(Mg,Fe)(Cr,Fe)2(Ti,Nb)2Si4O22 C 2/m 2/m
56.02.08.08 Maoniupingite-(Ce) ! (REE,Ca)4(Fe,Ti,Fe,[])(Ti,Fe,Fe,Nb)4Si4O22 C 2/m 2/m
56.02.08.09 Dingdaohengite-(Ce) ! (Ce,La)4Fe(Ti,Fe,Mg,Fe)2Ti2Si4O22 P 21 /a (pseudo-C 2/m) 2/m
Strunz Class:
09.BE.70 09 - SILICATES (Germanates)
09.B - Sorosilicates
09.BE -Si2O7 groups with additional anions;
09.BE.70 Chevkinite-(Ce) (Ce,La,Ca,Th)4(Fe,Mg)2(Ti,Fe)3Si4O22 C 2/m 2/m
09.BE.70 Karnasurtite-(Ce) (Ce,La,Th)(Ti,Nb)(Al,Fe)(Si,P)2O7(OH)4•3(H2O)(?) Unk. Hex
09.BE.70 Perrierite-(Ce) (Ce,La,Ca)4(Fe,Mg)2(Ti,Fe)3Si4O22 C 21/a 2/m
09.BE.70 Strontiochevkinite (Sr,REE)4Fe(Ti,Zr)2Ti2Si4O22 C 2/a 2/m
09.BE.70 Rengeite ! Sr4ZrTi4Si4O22 P 21 /a 2/m
09.BE.70 Maoniupingite-(Ce) ! (REE,Ca)4(Fe,Ti,Fe,[])(Ti,Fe,Fe,Nb)4Si4O22 C 2/m 2/m
09.BE.70 Matsubaraite ! Sr4TiTi4Si4O22 P 21 /a 2/m
09.BE.70 Polyakovite-(Ce) ! (Ce,La,Nd,Pr,Ca)4(Mg,Fe)(Cr,Fe)2(Ti,Nb)2Si4O22 C 2/m 2/m
09.BE.70 Dingdaohengite-(Ce) ! (Ce,La)4Fe(Ti,Fe,Mg,Fe)2Ti2Si4O22 P 21 /a (pseudo-C 2/m) 2/m
Other Chevkinite-(Ce) Information
References:
NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
See Also:
Links to other databases for Chevkinite-(Ce) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (UofA)
9 - MinDAT
10 - Mineralienatlas (Deutsch)
11 - Online Mineral Museum
12 - QUT Mineral Atlas
13 - Ruff.Info
14 - Uranium Minerals
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Chevkinite-(Ce)
(Ce,La,Ca,Th)4(Fe++,Mg)2(Ti,Fe+++)3Si4O22
Dana No: 56.02.08.01 Strunz No: 09.BE.70
Locality:
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