Mineralogy Database

Afwillite Mineral Data

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General Afwillite Information

Help on Chemical  Formula: Chemical Formula: Ca3Si2O4(OH)6
Help on Composition: Composition: Molecular Weight = 342.45 gm
   Calcium   35.11 %  Ca   49.13 % CaO
   Silicon   16.40 %  Si   35.09 % SiO2
   Hydrogen   1.77 %  H    15.78 % H2O
   Oxygen    46.72 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca3(Si2O4)(OH)6
Help on Environment: Environment: A product of contact metamorphism of limestones.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1925
Help on Locality: Locality: From the Dutoitspan diamond mine, Kimberley, and the Wessels mine, near Kuruman, Cape Province, South Africa. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: For Alpheus Fuller Williams (1874-1953), General Manager, DeBeers Consolidated Mines, Kimberley, South Africa.
Help on Name Pronunciation: Name Pronunciation: Afwillite + Pronunciation Say AFWILLITE
Help on Synonym: Synonym: ICSD 18
  PDF 29-330

Afwillite Image

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Comments: Crystallized afwillite prisms.
Location: Wessels Mine, Kalahari Manganese Field, Northern Cape Province, South Africa. Scale: Crystal size 1.5 mm.
© John Veevaert

Afwillite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =2.0822:1:2.393
Help on Cell Dimensions: Cell Dimensions: a = 11.39, b = 5.47, c = 13.09, Z = 4; beta = 98.433° V = 806.73 Den(Calc)= 2.82
Help on Crystal System: Crystal System: Monoclinic - Sphenoidal H-M Symbol (2) Space Group: P 21
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.83(1), 3.18(0.9), 6.61(0.9),

Physical Properties of Afwillite

Help on Cleavage: Cleavage: {001} Perfect, {???} Distinct
Help on Color: Color: Colorless, White.
Help on Density: Density: 2.62
Help on Diaphaneity: Diaphaneity: Transparent to Subtransparent to translucent
Help on Habit: Habit: Massive - Uniformly indistinguishable crystals forming large masses.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Hardness: Hardness: 3 - Calcite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Afwillite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.036 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.038 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2211,KPDmeas= 0.238,KC= 0.2298
Ncalc = 1.6 - 1.65
Help on Optical Data: Optical Data: Biaxial (+), a=1.6169, b=1.6204, g=1.6336, bire=0.0167

Calculated Properties of Afwillite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.66 gm/cc
note: Specific Gravity of Afwillite =2.62 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0083610278
Boson Index = 0.9916389722
Help on Photoelectric: Photoelectric: PEAfwillite = 4.90 barns/electron
U=PEAfwillite x rElectron Density= 13.06 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Afwillite is Not Radioactive

Afwillite Classification

Help on  Dana Class: Dana Class: (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O
  (52.04)with cations in [6] and/or > [6] coordination
  (52.04.07)Afwillite and related species Afwillite Ca3Si2O4(OH)6 P 21 2 Bultfonteinite Ca2SiO2(OH,F)4 P1 1 Hatrurite Ca3SiO5 R 3m 3m Jasmundite Ca11(SiO4)4O2S I 42m 4 2m
Help on  Strunz Class: Strunz Class: 09.AG.75 09 - SILICATES (Germanates)
  09.A - Nesosilicates
  09.AG -Nesosilicates with additional anions; cations in > [6] � [6] coordination
09.AG.75 Afwillite Ca3Si2O4(OH)6 P 21 2

Other Afwillite Information

Help on References: References: NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: See Also: Links to other databases for Afwillite :
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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Dana No: Strunz No: 09.AG.75





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