Zajacite-(Ce) Mineral Data

General Zajacite-(Ce) Information

Chemical Formula:

Na(REExCa1-x)(REEyCa1-y)F6 where (x ne y)

Composition:

Molecular Weight = 295.08 gm

Sodium 7.79 % Na 10.50 % Na₂O

Calcium 16.98 % Ca 23.76 % CaO

La,Ce,Pr,Nd,Sm, 36.60 % RE 42.70 % REE₂O₃

Fluorine 38.63 % F 38.63 % F

- % F -16.27 % -O=F₂

______ ______

100.00 % 99.32 % = TOTAL OXIDE

Empirical Formula:

NaREE_0.5Ca_0.5REE_0.25Ca_0.75F₆

Environment:

In a Precambrian perialkaline granitic complex.

IMA Status:

Approved IMA 1995

Locality:

The Strange Lake rare-earth-element deposit, about 250 km northeast of Schefferville, Quebec, on the Quebec-Labrador border, Canada. Link to MinDat.org Location Data.

Name Origin:

For Dr. Ihor Stephan Zajac (1935- ), the geologist who lead the exploration group that discovered the Strange Lake deposit and who first reconized the mineral.

Name Pronunciation:

Zajacite-(Ce)

Synonym:

IMA1993-038

Zajacite-(Ce) Image

Images:

Zajacite-(Ce)

Comments: Specimen of granodiorite hosting cream colored phenocrysts of zajacite-Ce. This is one of the few minerals (less than 20) that contain Praseodymium.
Location: Strange Lake, Lac Brasson, Quebec, Canada. Scale: 4.3 x 2.9 cm.
© John Veevaert

Zajacite-(Ce) Crystallography

Axial Ratios:

a:c = 1:1.81406

Cell Dimensions:

a = 6.099, c = 11.064, Z = 3; V = 356.42 Den(Calc)= 4.12

Crystal System:

Trigonal - Rhombohedral H-M Symbol ( 3) Space Group: P 3

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

By Intensity(I/I_o): 3.036(1), 1.757(0.8), 5.29(0.7),

Physical Properties of Zajacite-(Ce)

Cleavage:

None

Color:

Colorless, Pale pink, Orange.

Density:

4.44 - 4.55, Average = 4.49

Diaphaneity:

Transparent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Hardness:

3.5 - Copper Penny

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Zajacite-(Ce)

Optical Data:

Uniaxial (+), w=1.483, e=1.503, bire=0.0200.

Calculated Properties of Zajacite-(Ce)

Electron Density:

Bulk Density (Electron Density)=3.79 gm/cc
note: Specific Gravity of Zajacite-(Ce) =4.12 gm/cc.

Fermion Index:

Fermion Index = 0.06
Boson Index = 0.94

Photoelectric:

PE_{Zajacite-(Ce)}= 227.92 barns/electron
U=PE_{Zajacite-(Ce)} x r_electron= 863.98 barns/cc.

Radioactivity:

GRapi = 36,050.05 (Gamma Ray American Petroleum Institute Units)
Concentration of Zajacite-(Ce) per GRapi unit = 27.74 (PPM)

Zajacite-(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) 843.73 ±210.93 grams of pure Zajacite-(Ce) .

**Estimated Radioactivity from Zajacite-(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 / 7.74 cm	822,795	2.22E-05	36,050.05	11.85
100 gm / 3.59 cm	82,280	2.22E-06	3,605.00	1.19
10 gm / 1.67 cm	8,228	2.22E-07	360.50	0.12
1 gm / 7.74 mm	823	2.22E-08	36.05	0.01
0.1 gm / 3.59 mm	82	2.22E-09	3.61	0.00
0.01 gm / 1.67 mm	8	2.22E-10	0.36	0.00
0.001 gm / 0.77 mm	1	2.22E-11	0.04	0.00

Weight of pure Zajacite-(Ce) in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.12 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 ( 1.83 % Th) From Sum REE Elements (36.60 % REE)

Zajacite-(Ce) Classification

Dana Class:

11.05.07.01 (11)Halide Complexes; Alumino-fluorides

(11.05)where (A)m B (X)6

(11.05.07)Dana Group

11.05.07.01 Zajacite-(Ce) Na(REExCa1-x)(REEyCa1-y)F6where(xney) P 3 3

Strunz Class:

03.AB.35 03 - HALIDES

03.A - Simple Halides, Without H2O

03.AB -M:X = 1:2

03.AB.35 Gagarinite-(Y) NaCaY(F,Cl)6 P 3 3

03.AB.35 Zajacite-(Ce) Na(REExCa1-x)(REEyCa1-y)F6where(xney) P 3 3

Other Zajacite-(Ce) Information

References:

NAME( MinRec) PHYS. PROP.(Am.Min.,Vol.82,p1040,1997) OPTIC PROP.(MinRec)

See Also:

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

Search for Zajacite-(Ce) using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Zajacite-(Ce) :

Ask about Zajacite-(Ce) here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Zajacite-(Ce) Specimen Label here :

Zajacite-(Ce)

Na(REExCa1-x)(REEyCa1-y)F6 where (x ne y)
Dana No: 11.05.07.01 Strunz No: 03.AB.35
Locality:

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.