Burkeite Mineral Data

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General Burkeite Information

Chemical Formula:

Na6(CO3)(SO4)2

Composition:

Molecular Weight = 390.08 gm

Sodium 35.36 % Na 47.67 % Na₂O

Carbon 3.08 % C 11.28 % CO₂

Sulfur 16.44 % S 41.05 % SO₃

Oxygen 45.12 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₆(CO₃)(SO₄)₂

Environment:

Continental evaporite deposits.

IMA Status:

Valid Species (Pre-IMA) 1921

Locality:

Searles Lake, San Bernardino Co. California. Found in the lake clays as porphyroblastic crystals. Link to MinDat.org Location Data.

Name Origin:

Named for William Edmund Burke (1880-1966), chemical engineer, American Potash and Chemical Co., who discovered the artificial salt.

Name Pronunciation:

Burkeite

Synonym:

ICSD 71020

PDF 24-1134

Burkeite Image

Images:

Burkeite

Comments: Translucent to opaque vuggy mass of burkeite.
Location: Searles Lake, San Bernardino County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Burkeite Crystallography

Axial Ratios:

a:b:c =0.7654:1:0.1867

Cell Dimensions:

a = 21.15, b = 27.63, c = 5.16, Z = 12; V = 3,015.37 Den(Calc)= 2.58

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: P mmm

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

By Intensity(I/I_o): 2.78(1), 2.58(0.8), 3.78(0.8),

Forms:

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Forms: ( 0 1 0) ( 1 1 0) ( 1 0 0) ( 0 0 1)

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Crystal Structure:

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Giuseppetti G , Mazzi F , Tadini C , Neues Jahrbuch fur Mineralogie, Monatshefte , 1988 (1988) p.203-221, The crystal structure of synthetic burkeite Na4SO4(CO3)t(SO4)1-t, Sample A, Note sign of y-coordinate for O3 and O5 altered to reproduce reported bond lengths, Locality: synthetic

View Additional jPOWD Structure files for Burkeite
[1] [2]

Physical Properties of Burkeite

Cleavage:

{???} Indistinct

Color:

Gray, Gray white, White, Light brown, Pink.

Density:

2.57

Diaphaneity:

Transparent

Fracture:

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

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Nodular - Tuberose forms having irregular protuberances over the surface.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

3.5 - Copper Penny

Luminescence:

Fluorescent and phosphorescent, Short UV=yellow-white, Long UV=yellow-white.

Luster:

Vitreous - Greasy

Streak:

white

Optical Properties of Burkeite

Gladstone-Dale:

CI meas= 0.008 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.012 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1848,KPDmeas= 0.1855,KC= 0.187
Ncalc = 1.48

Optical Data:

Biaxial (-), a=1.448, b=1.489, g=1.493, bire=0.0450, 2V(Calc)=32, 2V(Meas)=34. Dispersion r > v distinct.

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Calculated Properties of Burkeite

Electron Density:

Bulk Density (Electron Density)=2.53 gm/cc
note: Specific Gravity of Burkeite =2.57 gm/cc.

Fermion Index:

Fermion Index = 0.0017883428
Boson Index = 0.9982116572

Photoelectric:

PE_Burkeite= 1.59 barns/electron
U=PE_Burkeite x rElectron Density= 4.03 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Burkeite is Not Radioactive

Burkeite Classification

Dana Class:

32.01.01.01 (32)Compound Sulfates

(32.01)(anhydrous) with simple bi-anionic formula

(32.01.01)Dana Group

32.01.01.01 Burkeite Na6(CO3)(SO4)2 P mmm 2/m 2/m 2/m

Strunz Class:

07.BD.25 07 - SULFATES (SELENATES, TELLURATES)

07.B - Sulfates (selenates, etc.) with Additional Anions, without H2O

07.BD -With only large cations

07.BD.25 Burkeite Na6(CO3)(SO4)2 P mmm 2/m 2/m 2/m

Other Burkeite Information

See Also:

Links to other databases for Burkeite :
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 (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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

Burkeite

Na6(CO3)(SO4)2
Dana No: 32.01.01.01 Strunz No: 07.BD.25
Locality:

Notes: