Langbeinite Mineral Data

Langbeinite Mineral Data +

General Langbeinite Information

Chemical Formula:

K2Mg2(SO4)3

Composition:

Molecular Weight = 415.00 gm

Potassium 18.84 % K 22.70 % K₂O

Magnesium 11.71 % Mg 19.42 % MgO

Sulfur 23.18 % S 57.88 % SO₃

Oxygen 46.26 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

K₂Mg₂(SO₄)₃

Environment:

Marine evaporite deposits.

IMA Status:

Valid Species (Pre-IMA) 1891

Locality:

Link to MinDat.org Location Data.

Synonym:

ICSD 100420

PDF 19-975

Langbeinite Image

Images:

Langbeinite

Comments: Pale brownish pink crystalline aggregate of langbeinite.
Location: Carlsbad, Eddy County, New Mexico, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Langbeinite Crystallography

Cell Dimensions:

a = 9.9211, Z = 4; V = 976.52 Den(Calc)= 2.82

Crystal System:

Isometric - TetartoidalH-M Symbol (2 3) Space Group: P 2₁3

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

By Intensity(I/I_o): 3.14(1), 2.65(0.35), 4.05(0.25),

Forms:

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Forms: [ 1 0 2] [ 1 1 1] [ 1 1 1] [ 1 1 2] [ 0 0 1]

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Crystal Structure:

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Speer D , Salje E , Physics and Chemistry of Minerals , 13 (1986) p.17-24, Phase transitions in langbeinites I: Crystal chemistry, and structures of K-double sulfates of the langbeinite, type M2++K2(SO4)3, M++=Mg,Ni,Co,Zn,Ca, Sample: K2Ca2(SO4)3, T = 260 C

View Additional jPOWD Structure files for Langbeinite
[1] [2] [3] [4] [5]

Physical Properties of Langbeinite

Cleavage:

None

Color:

Colorless, Violet, Greenish, Gray, Yellowish.

Density:

2.83

Diaphaniety:

Transparent to Translucent

Fracture:

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

Hardness:

3.5-4 - Copper Penny-Fluorite

Luminescence:

Phosphorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Langbeinite

Gladstone-Dale:

CI meas= -0.019 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.023 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1901,KPDmeas= 0.1894,KC= 0.1858

Optical Data:

Isotropic, n=1.536.

Calculated Properties of Langbeinite

Electron Density:

r_electron=2.81 gm/cc
note: r_Langbeinite=2.83 gm/cc.

Fermion Index

Fermion Index = 0.01369
Boson Index = 0.98631

Photoelectric:

PE_Langbeinite= 3.54 barns/electron
U=PE_Langbeinite x r_electron= 9.95 barns/cc.

Radioactivity:

GRapi = 269.89 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Langbeinite - barely detectable

Langbeinite Classification

Dana Class:

28.4.4.1 (28)Anhydrous Acid and Sulfates

(28.4)with miscellaneous formulae

(28.4.4)Dana Group

28.4.4.1 Langbeinite K2Mg2(SO4)3 P 2₁3 2 3

28.4.4.2 Manganolangbeinite K2Mn2(SO4)3 P 2₁3 2 3

28.4.4.3 Efremovite (NH4)2Mg2(SO4)3 P 2₁3 2 3

Strunz Class:

VI/A.03-10 VI - Sulfates,Chromates,Molybdates and Tungstates

VI/A - Waterfree sulfates [SO4]2- without unfamiliar anions. cations of medium and very big size

VI/A.03 - Langbeinite - Efremovite series

VI/A.03-10 Langbeinite K2Mg2(SO4)3 P 2₁3 2 3

VI/A.03-20 Manganolangbeinite K2Mn2(SO4)3 P 2₁3 2 3

VI/A.03-30 Efremovite (NH4)2Mg2(SO4)3 P 2₁3 2 3

Other Langbeinite Information

References:

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

See Also:

Links to other databases for Langbeinite :
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 - WWW-MINCRYST 13 -École des Mines de Paris

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

Langbeinite

K2Mg2(SO4)3
Dana No: 28.4.4.1 Strunz No: VI/A.03-10
Locality:

Notes: