Ewaldite Mineral Data

Ewaldite Mineral Data +

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General Ewaldite Information

Chemical Formula:

(Ba,Sr)(Ca,Na,Y,Ce)(CO3)2

Composition:

Molecular Weight = 294.76 gm

Barium 34.94 % Ba 39.01 % BaO

Sodium 2.34 % Na 3.15 % Na₂O

Strontium 7.43 % Sr 8.79 % SrO

Calcium 6.80 % Ca 9.51 % CaO

Cerium 4.75 % Ce 5.57 % Ce₂O₃

Yttrium 3.02 % Y 3.83 % Y₂O₃

Carbon 8.15 % C 29.86 % CO₂

Oxygen 32.57 % O

______ ______

100.00 % 99.73 % = TOTAL OXIDE

Empirical Formula:

Ba_0.75Sr_0.25Ca_0.5Na_0.3Y_0.1Ce_0.1(CO₃)₂

Environment:

Eocene-aged lacustrine deposits.

IMA Status:

Approved IMA 1971

Locality:

Green River Formation, Sweetwater County, Wyoming, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Paul P. Ewald (1888-1985), German crystallographer, founder of Acta Crystallographica, and professor at Brooklyn Polytechnical Institute, New, York.

Synonym:

ICSD 27421

PDF 46-1453

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Ewaldite Crystallography

Axial Ratios:

a:c = 1:2.41387

Cell Dimensions:

a = 5.318, c = 12.837, Z = 2; V = 314.41 Den(Calc)= 3.11

Crystal System:

Hexagonal - Dihexagonal PyramidalH-M Symbol (6mm) Space Group: P 6₃mc

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

By Intensity(I/I_o): 6.39(1), 3.72(0.4), 4.58(0.2),1.714(0.1), 2.44(0.1), 3.2(0.1),

Physical Properties of Ewaldite

Cleavage:

None

Color:

Bluish green, Greenish gray, White.

Density:

3.25

Diaphaniety:

Transparent

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Streak:

white

Optical Properties of Ewaldite

Dichroism (e):

pale yellow green.

Dichroism (w):

dark blue green.

Gladstone-Dale:

CI meas= -0.128 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.178 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1958,KPDmeas= 0.1874,KC= 0.1662

Optical Data:

Uniaxial (-), e=1.572, w=1.646, bire=0.0740.

Calculated Properties of Ewaldite

Electron Density:

r_electron=2.97 gm/cc
note: r_Ewaldite=3.25 gm/cc.

Fermion Index

Fermion Index = 0.06862
Boson Index = 0.93138

Photoelectric:

PE_Ewaldite= 191.06 barns/electron
U=PE_Ewaldite x r_electron= 566.67 barns/cc.

Radioactivity:

GRapi = 4,627.40 (Gamma Ray American Petroleum Institute Units)

Ewaldite is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.

**Estimated Radioactivity from Ewaldite** - mild
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 / 8.38 cm	106,480	2.88E-06	4,627.40	1.52
100 gm / 3.89 cm	10,648	2.88E-07	462.74	0.15
10 gm / 1.80 cm	1,065	2.88E-08	46.27	0.02
1 gm / 8.38 mm	106	2.88E-09	4.63	0.00
0.1 gm / 3.89 mm	11	2.88E-10	0.46	0.00
0.01 gm / 1.80 mm	1	2.88E-11	0.05	0.00
0.001 gm / 0.84 mm	0	2.88E-12	0.00	0.00

Weight of pure Ewaldite in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.25 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 ( 0.24 % Th) From Sum REE Elements ( 4.75 % REE)

Ewaldite Classification

Dana Class:

14.2.4.1 (14)Anhydrous Carbonates

(14.2)with Compound Formula A+ B++ (CO3)2

(14.2.4)Dana Group

14.2.4.1 Ewaldite (Ba,Sr)(Ca,Na,Y,Ce)(CO3)2 P 6₃mc 6mm

Strunz Class:

V/D.04-05 V - Nitrates, Carbonates and Borates

V/D - Water-bearing carbonates without unfamiliar anions

V/D.04 - Donnayite-(Y) - Weloganite series

V/D.04-05 Ewaldite (Ba,Sr)(Ca,Na,Y,Ce)(CO3)2 P 6₃mc 6mm

V/D.04-10 Donnayite-(Y) Sr3NaCaY(CO3)6·3(H2O) P1 1

V/D.04-20 Mckelveyite-(Y) Ba3Na(Ca,U)Y(CO3)6·3(H2O) P1 1

V/D.04-25 Mckelveyite-(Nd)* (Ba,Sr)(Ca,Na,Nd,REE)(CO3)2·3-10(H2O) P1 1

V/D.04-30 Weloganite Sr3Na2Zr(CO3)6·3(H2O) P1 1

Other Ewaldite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

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Ewaldite

(Ba,Sr)(Ca,Na,Y,Ce)(CO3)2
Dana No: 14.2.4.1 Strunz No: V/D.04-05
Locality:

Notes: