Leucite Mineral Data

General Leucite Information

Chemical Formula:

KAlSi2O6

Composition:

Molecular Weight = 218.25 gm

Potassium 17.91 % K 21.58 % K₂O

Aluminum 12.36 % Al 23.36 % Al₂O₃

Silicon 25.74 % Si 55.06 % SiO₂

Oxygen 43.99 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

KAl(Si₂O₆)

Environment:

Acid volcanic rocks.

IMA Status:

Valid Species (Pre-IMA) 1791

Locality:

Bearpaw Mountains., Montana, USA. Link to MinDat.org Location Data.

Name Origin:

From the Greek leukos - "white."

Name Pronunciation:

Leucite

Synonym:

Amphigene

Leucite Image

Images:

Leucite

Comments: Large single crystal of dark gray leucite.
Location: Roccamonfina, Caserta Province, Campania, Italy. Scale: 20x20x20 mm.
© John Betts - Fine Minerals

Leucite Crystallography

Axial Ratios:

a:c = 1:1.05042

Cell Dimensions:

a = 13.09, c = 13.75, Z = 16; V = 2,356.04 Den(Calc)= 2.46

Crystal System:

Tetragonal - Dipyramidal H-M Symbol (4/m) Space Group: I 4₁/a

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

By Intensity(I/I_o): 3.266(1), 3.438(0.85), 5.39(0.8),

Physical Properties of Leucite

Cleavage:

{110} Indistinct

Color:

Colorless, Gray, Yellow gray, White.

Density:

2.47

Diaphaneity:

Translucent to transparent

Fracture:

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

Habit:

Crystalline - Coarse - Occurs as well-formed coarse sized crystals.

Hardness:

6 - Orthoclase

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Magnetism:

Nonmagnetic

Streak:

white

Optical Properties of Leucite

Gladstone-Dale:

CI meas= -0.006 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.01 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2072,KPDmeas= 0.2064,KC= 0.2052
Ncalc = 1.5 - 1.51

Optical Data:

Isotropic, n=1.508-1.511.

Calculated Properties of Leucite

Electron Density:

Bulk Density (Electron Density)=2.44 gm/cc
note: Specific Gravity of Leucite =2.47 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Leucite= 3.14 barns/electron
U=PE_Leucite x r_electron= 7.67 barns/cc.

Radioactivity:

GRapi = 255.81 (Gamma Ray American Petroleum Institute Units)
Concentration of Leucite per GRapi unit = 0.39 (%)

Estimated Radioactivity from Leucite - barely detectable

Leucite Classification

Dana Class:

76.02.02.01 (76)Tectosilicate Al-Si Framework

(76.02)Feldspathoids and related species

(76.02.02)Leucite group

76.02.02.01 Leucite KAlSi2O6 I 4₁/a 4/m

76.02.02.02 Ammonioleucite (NH4,K)AlSi2O6 I 4₁/a 4/m

Strunz Class:

09.GB.05 09 - SILICATES (Germanates)

09.G - Tektosilicates with Zeolitic H2O

09.GB -Chains of single connected 4-membered rings

09.GB.05 Ammonioleucite (NH4,K)AlSi2O6 I 4₁/a 4/m

09.GB.05 Analcime NaAlSi2O6•(H2O) P1 1

09.GB.05 Hsianghualite Ca3Li2Be3(SiO4)3F2 I 2₁3 2 3

09.GB.05 Lithosite K6Al4Si8O25•(H2O) P 2₁ (pseudo ORTH) 2

09.GB.05 Leucite KAlSi2O6 I 4₁/a 4/m

09.GB.05 Pollucite (Cs,Na)2Al2Si4O12•(H2O) I a3d 4/m 3 2/m

09.GB.05 Wairakite CaAl2Si4O12•2(H2O) I2/a 2/m

Other Leucite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Mason68)

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

Leucite

KAlSi2O6
Dana No: 76.02.02.01 Strunz No: 09.GB.05
Locality:

Notes:

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