Lourenswalsite Mineral Data

Lourenswalsite Mineral Data +

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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.

Lourenswalsite Image

Images:

Click Here for Larger Lourenswalsite Image

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:

HexagonalSpace 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

Diaphaniety:

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= 0.031 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.038 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2607,KPDmeas= 0.2624,KC= 0.2709

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:

r_electron=3.09 gm/cc
note: r_{Lourenswalsite}=3.17 gm/cc.

Fermion Index

Fermion Index = 0.04902
Boson Index = 0.95098

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)

Estimated Radioactivity from Lourenswalsite - barely detectable

Lourenswalsite Classification

Dana Class:

61.2.3.1 (61)Cyclosilicate Six-Membered Rings

(61.2)with Al substituted rings

(61.2.3)Dana Group

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

Strunz Class:

VIII/H.38-80 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica minerals with tetrahedral-double layers and related structures

VIII/H.38 - Monteregianite-(Y) - Wickenburgite series

VIII/H.38-10 Monteregianite-(Y) (Na,K)6(Y,Ca)2Si16O38·10(H2O) P 2₁/m 2/m

VIII/H.38-20 Rhodesite KHCa2Si8O19·5(H2O) Pmam 2/m 2/m 2/m

VIII/H.38-30 Delhayelite (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3·18(H2O) Pnmm 2/m 2/m 2/m

VIII/H.38-40 Hydrodelhayelite KCa2AlSi7O17(OH)2·6(H2O) Pnm21 mm2

VIII/H.38-50 Macdonaldite BaCa4[Si16O36(OH)2]·10(H2O) C mcm 2/m 2/m 2/m

VIII/H.38-60 Cymrite BaAl2Si2O8·(H2O) P 2₁ (pseudo-HEX) 2

VIII/H.38-65 Kampfite! Ba6[(Si,Al)O2]8(CO3)2Cl2(Cl,H2O)2 P 6₃mmc, P 6₂c, P 6₃mc, P 3₁ Hex

VIII/H.38-80 Lourenswalsite (K,Ba)2(Ti,Mg,Ca,Fe)4(Si,Al,Fe)6O14(OH)12 Unk (pseudo-HEX) Hex

VIII/H.38-90 Wickenburgite Pb3CaAl2Si10O27·4(H2O) P 3₁c 3m

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 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (MinSocAm) 7 -Handbook of Mineralogy (UofA) 8 -MinDAT 9 -MinMax(Deutsch) 10 -MinMax(English) 11 -Mineralienatlas (Deutsch) 12 -QUT Mineral Atlas 13 -École des Mines de Paris

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Lourenswalsite

(K,Ba)2(Ti,Mg,Ca,Fe)4(Si,Al,Fe)6O14(OH)12
Dana No: 61.2.3.1 Strunz No: VIII/H.38-80
Locality:

Notes: