Mineralogy Database

Petalite Mineral Data

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General Petalite Information

Help on Chemical  Formula: Chemical Formula: LiAlSi4O10
Help on Composition: 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
Help on Empirical Formula: Empirical Formula: Li0.92Al0.99Si3.99O10
Help on Environment: Environment: In granite pegmatites, locally constituting an ore of lithium.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1800
Help on Locality: Locality: Mining Academy, Freiberg, Germany, Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: From the Greek petalon - "leaf" in allusion to the perfect basal cleavage.
Help on Name Pronunciation: Name Pronunciation: Petalite Say PETALITE
Help on Synonym: Synonym: ICSD 100348
  PDF 35-463

Petalite Image

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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

Help on Axial Ratios: Axial Ratios: a:b:c =2.2869:1:1.4845
Help on Cell Dimensions: Cell Dimensions: a = 11.754, b = 5.1395, c = 7.6296, Z = 2; beta = 113.04° V = 424.14 Den(Calc)= 2.39
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2/a
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 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),

Physical Properties of Petalite

Help on Cleavage: Cleavage: {001} Perfect, {???} Imperfect
Help on Color: Color: Colorless, Gray, Yellow, Yellow gray, White.
Help on Density: Density: 2.39 - 2.46, Average = 2.42
Help on Diaphaneity: Diaphaneity: Transparent to translucent
Help on Fracture: Fracture: Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.
Help on Habit: Habit: Massive - Uniformly indistinguishable crystals forming large masses.
Help on Hardness: Hardness: 6-6.5 - Orthoclase-Pyrite
Help on Luminescence: Luminescence: Non-Fluorescent.
Help on Luster: Luster: Vitreous - Pearly
Help on Streak: Streak: colorless

Optical Properties of Petalite

Help on Gladstone-Dale: 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
Help on Optical Data: Optical Data: Biaxial (+), a=1.504, b=1.51, g=1.516, bire=0.0120

Calculated Properties of Petalite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.41 gm/cc
note: Specific Gravity of Petalite =2.43 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEPetalite = 1.69 barns/electron
U=PEPetalite x rElectron Density= 4.06 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Petalite is Not Radioactive

Petalite Classification

Help on  Dana Class: Dana Class: (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
  (72.06)with tetrahedral Al cross-linking
  (72.06.01)Dana Group Petalite LiAlSi4O10 P 2/a 2/m
Help on  Strunz Class: 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

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)
Help on See Also: 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

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Dana No: Strunz No: 09.EF.05





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