Petalite Mineral Data

General Petalite Information

Chemical Formula:

LiAlSi4O10

Composition:

Molecular Weight = 305.15 gm

Lithium 2.09 % Li 4.50 % Li₂O

Aluminum 8.75 % Al 16.54 % Al₂O₃

Silicon 36.72 % Si 78.56 % SiO₂

Oxygen 52.43 % O

______ ______

100.00 % 99.61 % = TOTAL OXIDE

Empirical Formula:

Li_0.92Al_0.99Si_3.99O₁₀

Environment:

In granite pegmatites, locally constituting an ore of lithium.

IMA Status:

Valid Species (Pre-IMA) 1800

Locality:

Mining Academy, Freiberg, Germany, Link to MinDat.org Location Data.

Name Origin:

From the Greek petalon - "leaf" in allusion to the perfect basal cleavage.

Name Pronunciation:

Petalite

Synonym:

ICSD 100348

PDF 35-463

Petalite Image

Images:

Petalite

Comments: Translucent, gemmy , equant petalite crystal with an etched surface texture resulting in irregular faces.
Location: Paprok, Konar (Kunar; Konarh; Konarha; Nuristan) Province, Afghanistan. Scale: 5x3.5x3 cm.
© John Betts - Fine Minerals

Petalite Crystallography

Axial Ratios:

a:b:c =2.2869:1:1.4845

Cell Dimensions:

a = 11.754, b = 5.1395, c = 7.6296, Z = 2; beta = 113.04° V = 424.14 Den(Calc)= 2.39

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2/a

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

By Intensity(I/I_o): 3.731(1), 3.672(0.34), 3.649(0.24),3.51(0.16), 1.934(0.07), 2.57(0.06), 2.071(0.05),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Tagai T , Ried H , Joswig W , Korekawa M , Zeitschrift fur Kristallographie , 160 (1982) p.159-170, Kristallographische untersuchungen eines petalits mittels neutronenbeugung und, transmissionselektronenmikroskopie, Locality: Varutrask, Sweden

Physical Properties of Petalite

Cleavage:

{001} Perfect, {???} Imperfect

Color:

Colorless, Gray, Yellow, Yellow gray, White.

Density:

2.39 - 2.46, Average = 2.42

Diaphaneity:

Transparent to translucent

Fracture:

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

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

6-6.5 - Orthoclase-Pyrite

Luminescence:

Non-Fluorescent.

Luster:

Vitreous - Pearly

Streak:

colorless

Optical Properties of Petalite

Gladstone-Dale:

CI meas= 0.006 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.009 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2134,KPDmeas= 0.2103,KC= 0.2115
Ncalc = 1.51 - 1.52

Optical Data:

Biaxial (+), a=1.504, b=1.51, g=1.516, bire=0.0120

Calculated Properties of Petalite

Electron Density:

Bulk Density (Electron Density)=2.41 gm/cc
note: Specific Gravity of Petalite =2.43 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Petalite= 1.69 barns/electron
U=PE_Petalite x rElectron Density= 4.06 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Petalite is Not Radioactive

Petalite Classification

Dana Class:

72.06.01.01 (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings

(72.06)with tetrahedral Al cross-linking

(72.06.01)Dana Group

72.06.01.01 Petalite LiAlSi4O10 P 2/a 2/m

Strunz Class:

09.EF.05 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EF -Single nets with 6-membered rings, ± other rings

09.EF.05 Petalite LiAlSi4O10 P 2/a 2/m

Other Petalite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

See Also:

Links to other databases for Petalite :
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
15 - Scandinavian mineral gallery
16 - Tradeshop.com - The Rainbow of Gems
17 - WWW-MINCRYST

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Ask about Petalite here :
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Mindat.org's Discussion Groups
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Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Petalite

LiAlSi4O10
Dana No: 72.06.01.01 Strunz No: 09.EF.05
Locality:

Notes: