Ekanite Mineral Data

Ekanite Mineral Data +

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General Ekanite Information

Chemical Formula:

ThCa2Si8O20

Composition:

Molecular Weight = 856.87 gm

Calcium 9.35 % Ca 13.09 % CaO

Thorium 27.08 % Th 30.81 % ThO₂

Silicon 26.22 % Si 56.10 % SiO₂

Oxygen 37.34 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

ThCa₂Si₈O₂₀

IMA Status:

Approved IMA 1961

Locality:

Link to MinDat.org Location Data.

Synonym:

ICSD 64745

PDF 35-532

Ekanite Image

Images:

Ekanite

Comments: Complex specimen of many minerals, most notable are four red ekanite crystals (rare!) scattered around the specimen.
Location: Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mt Saint-Hilaire, Rouville Co., Qu?bec, Canada. Scale: 6x4x4 cm.
© John Betts - Fine Minerals

Ekanite Crystallography

Axial Ratios:

a:c = 1:1.99024

Cell Dimensions:

a = 7.483, c = 14.893, Z = 2; V = 833.94 Den(Calc)= 3.41

Crystal System:

Tetragonal - TrapezohedralH-M Symbol (4 2 2) Space Group: I 422

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

By Intensity(I/I_o): 4.14(1), 3.34(0.96), 6.69(0.61),

Crystal Structure:

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Szymanski J T , Owens D R , Roberts A C , Ansell H G , Chao G Y , The Canadian Mineralogist , 20 (1982) p.65-75, A mineralogical study and crystal-structure determination of, nonmetamict ekanite, ThCa2Si8O20, Note: Changed O2-x coordinate to match reported bond lengths

Physical Properties of Ekanite

Cleavage:

[101] Distinct

Color:

Green, Yellow, Dark red.

Density:

3.08

Diaphaniety:

Translucent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Ekanite

Gladstone-Dale:

CI meas= 0.047 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.14 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1683,KPDmeas= 0.1864,KC= 0.1956

Optical Data:

Uniaxial (-), e=1.568, w=1.58, bire=0.0120.

Calculated Properties of Ekanite

Electron Density:

r_electron=2.89 gm/cc
note: r_Ekanite=3.08 gm/cc.

Fermion Index

Fermion Index = 0.01255
Boson Index = 0.98745

Photoelectric:

PE_Ekanite= 609.37 barns/electron
U=PE_Ekanite x r_electron=1,761.05 barns/cc.

Radioactivity:

GRapi = 542,060.77 (Gamma Ray American Petroleum Institute Units)

Ekanite 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) 56.11 ± 14.03 grams of pure Ekanite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 5611.3 ±1402.8 grams of pure Ekanite .

**Estimated Radioactivity from Ekanite** - strong
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 / 8.53 cm	12,131,773	3.28E-04	542,060.77	178.21
100 gm / 3.96 cm	1,213,177	3.28E-05	54,206.08	17.82
10 gm / 1.84 cm	121,318	3.28E-06	5,420.61	1.78
1 gm / 8.53 mm	12,132	3.28E-07	542.06	0.18
0.1 gm / 3.96 mm	1,213	3.28E-08	54.21	0.02
0.01 gm / 1.84 mm	121	3.28E-09	5.42	0.00
0.001 gm / 0.85 mm	12	3.28E-10	0.54	0.00

Weight of pure Ekanite in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.08 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

Ekanite Classification

Dana Class:

72.1.1.1 (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings

(72.1)with 4-membered rings

(72.1.1)Dana Group

72.1.1.1 Ekanite ThCa2Si8O20 I 422 4 2 2

Strunz Class:

VIII/E.10-10 VIII - Silicates

VIII/E - Cyklosilicates, double quadruplet rings [Si8O20]8-

VIII/E.10 - Ekanite - Steacyite series

VIII/E.10-10 Ekanite ThCa2Si8O20 I 422 4 2 2

VIII/E.10-20 Iraqite-(La) K(La,Ce,Th)2(Ca,Na)4(Si,Al)16O40 P 4/mcc 4/m 2/m 2/m

VIII/E.10-30 Steacyite K1-x(Ca,Na)2ThSi8O20(x=0.2to0.4) P 4/mcc 4/m 2/m 2/m

VIII/E.10-40 Turkestanite! Th(Ca,Na)2(K1-x,[]x)Si8O20·n(H2O) P 4/mcc 4/m 2/m 2/m

Other Ekanite Information

References:

PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

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Print or Cut-and-Paste your Ekanite Specimen Label here :

Ekanite

ThCa2Si8O20
Dana No: 72.1.1.1 Strunz No: VIII/E.10-10
Locality:

Notes: