Burkeite Mineral Data

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.

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

Diaphaniety:

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:

Phosphorescent fluorescent.

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

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.

Pleochroism (z):

colorless.

Calculated Properties of Burkeite

Electron Density:

r_electron=2.53 gm/cc
note: r_Burkeite=2.57 gm/cc.

Fermion Index

Fermion Index = 0.00178
Boson Index = 0.99822

Photoelectric:

PE_Burkeite= 1.59 barns/electron
U=PE_Burkeite x r_electron= 4.03 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Burkeite is Not Radioactive

Burkeite Classification

Dana Class:

32.1.1.1 (32)Compound Sulfates

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

(32.1.1)Dana Group

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

Strunz Class:

VI/B.14-20 VI - Sulfates,Chromates,Molybdates and Tungstates

VI/B - Waterfree sulfates [SO4]2- with unfamiliar anions. mostly big cations

VI/B.14 - Hectorfloresite - Hanksite series

VI/B.14-10 Hectorfloresite Na9(IO3)(SO4)4 P 2₁/a 2/m

VI/B.14-20 Burkeite Na6(CO3)(SO4)2 P mmm 2/m 2/m 2/m

VI/B.14-30 Hanksite KNa22(SO4)9(CO3)2Cl P 6₃/m 6/m

Other Burkeite Information

References:

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

See Also:

Links to other databases for Burkeite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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

Burkeite

Na6(CO3)(SO4)2
Dana No: 32.1.1.1 Strunz No: VI/B.14-20
Locality:

Notes: