Lourenswalsite Mineral Data

General Lourenswalsite Information

Chemical Formula:

(K,Ba)2(Ti,Mg,Ca,Fe)4(Si,Al,Fe)6O14(OH)12

Composition:

Molecular Weight = 937.50 gm

Potassium 5.00 % K 6.03 % K₂O

Barium 10.25 % Ba 11.45 % BaO

Calcium 0.43 % Ca 0.60 % CaO

Magnesium 1.04 % Mg 1.72 % MgO

Titanium 17.36 % Ti 28.97 % TiO₂

Aluminum 2.88 % Al 5.44 % Al₂O₃

Iron 4.17 % Fe 0.77 % FeO / 5.11 % Fe₂O₃

Silicon 13.18 % Si 28.20 % SiO₂

Hydrogen 1.31 % H 11.72 % H₂O

Oxygen 44.37 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

K_1.2Ba_0.7Ti_3.4Mg_0.4Ca_0.1Fe²⁺_0.1Si_4.4AlFe³⁺_0.6O_19.9(H₂O)_6.1

Environment:

Oxidizing conditions.

IMA Status:

Approved IMA 1987

Locality:

Diamond Jo quarry, Magnet Cove, near Hot Springs, Arkansas, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Lourens Wals (1939-), a leading Belgian mineral collector.

Name Pronunciation:

Lourenswalsite + Pronunciation

Lourenswalsite Image

Images:

Lourenswalsite Aegirine

Comments: Light brownish rosettes of lourenswalsite with dark green crystals of aegirine and white feldspar.
Location: Diamond Jo quarry, Magnet Cove, Hot Springs Co., Arkansas, USA. Scale: Picture size 3 mm.
© Thomas Witzke / Abraxas-Verlag

Lourenswalsite Crystallography

Axial Ratios:

a:c = 1:3.90732

Cell Dimensions:

a = 5.244, c = 20.49, Z = 1; V = 487.98 Den(Calc)= 3.19

Crystal System:

Hexagonal Space Group: Unk (pseudo-HEX)

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

By Intensity(I/I_o): 2.608(1), 1.515(0.8), 1.3111(0.25),

Physical Properties of Lourenswalsite

Cleavage:

{001} Good

Color:

Brownish gray, Pearl gray.

Density:

3.17

Diaphaneity:

Translucent

Fracture:

Friable - The crumbly disintegration of earthy materials or highly fractured minerals.

Habit:

Pseudo Hexagonal - Crystals show a hexagonal outline.

Habit:

Rosette - Bundled tabular aggregates resembling rose flower petals.

Luster:

Pearly

Streak:

gray white

Optical Properties of Lourenswalsite

Gladstone-Dale:

CI meas= 0.037 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.043 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2607,KPDmeas= 0.2624,KC= 0.2723
Ncalc = 1.86 - 1.87

Optical Data:

Biaxial (-), a=1.815, b=1.84, g=1.84, bire=0.0250

Pleochroism (x):

none.

Pleochroism (y):

none.

Pleochroism (z):

none.

Calculated Properties of Lourenswalsite

Electron Density:

Bulk Density (Electron Density)=3.09 gm/cc
note: Specific Gravity of Lourenswalsite =3.17 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_{Lourenswalsite}= 47.51 barns/electron
U=PE_{Lourenswalsite} x r_electron= 146.70 barns/cc.

Radioactivity:

GRapi = 70.32 (Gamma Ray American Petroleum Institute Units)
Concentration of Lourenswalsite per GRapi unit = 1.42 (%)

Estimated Radioactivity from Lourenswalsite - barely detectable

Lourenswalsite Classification

Dana Class:

61.02.03.01 (61)Cyclosilicate Six-Membered Rings

(61.02)with Al substituted rings

(61.02.03)Dana Group

61.02.03.01 Lourenswalsite (K,Ba)2(Ti,Mg,Ca,Fe)4(Si,Al,Fe)6O14(OH)12 Unk (pseudo-HEX) Hex

Strunz Class:

09.EJ.05 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EJ -Unclassified phyllosilicates

09.EJ.05 Lourenswalsite (K,Ba)2(Ti,Mg,Ca,Fe)4(Si,Al,Fe)6O14(OH)12 Unk (pseudo-HEX) Hex

Other Lourenswalsite Information

References:

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

See Also:

Links to other databases for Lourenswalsite :
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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Lourenswalsite

(K,Ba)2(Ti,Mg,Ca,Fe)4(Si,Al,Fe)6O14(OH)12
Dana No: 61.02.03.01 Strunz No: 09.EJ.05
Locality:

Notes:

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