Mineralogy Database

Ahlfeldite Mineral Data

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General Ahlfeldite Information

Help on Chemical  Formula: Chemical Formula: (Ni,Co)SeO3•2(H2O)
Help on Composition: Composition: Molecular Weight = 221.74 gm
   Cobalt     6.64 %  Co    8.45 % CoO
   Nickel    19.85 %  Ni   25.26 % NiO
   Hydrogen   1.82 %  H    16.25 % H2O
   Selenium  35.61 %  Se   50.04 % SeO2
   Oxygen    36.08 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ni0.75Co0.25(SeO3)•2(H2O)
Help on Environment: Environment: Formed as an alteration product of penroseeite and other selenides.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1935
Help on Locality: Locality: Bolivia, Potos�, Colquechaca Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Federico Ahlfeld (1892-192), German-Bolivian geologist and mineralogist who studied Bolivian minerals.
Help on Name Pronunciation: Name Pronunciation: Ahlfeldite + Pronunciation Say AHLFELDITE
Help on Synonym: Synonym: ICSD 69220
  PDF 25-1233

Ahlfeldite Image

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Comments: Green encrustations of ahlfeldite on matrix.
Location: Mina El Dragon, Potosi, Bolivia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Ahlfeldite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.8595:1:0.734
Help on Cell Dimensions: Cell Dimensions: a = 7.53, b = 8.76, c = 6.43, Z = 4; beta = 99.083° V = 418.82 Den(Calc)= 3.52
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21/m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 5.69(1), 3.426(0.8), 2.992(0.75),
Help on Forms: Forms:

Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize

S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu

Help on Above

Forms: ( 0 2 1) ( 1 1 0) ( 1 0 3) ( 1 0 1) ( 0 1 1)

Warning: this java applet does not work in some browsers because of security restrictions.


Physical Properties of Ahlfeldite

Help on Cleavage: Cleavage: {110} Distinct, {103} Distinct
Help on Color: Color: Pink brown, Apple green, Red.
Help on Density: Density: 3.37
Help on Diaphaneity: Diaphaneity: Transparent
Help on Fracture: Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Hardness: Hardness: 2-2.5 - Gypsum-Finger Nail
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: light green

Optical Properties of Ahlfeldite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.04 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.004 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2115,KPDmeas= 0.2209,KC= 0.2124
Ncalc = 1.72 - 1.75
Help on Optical Data: Optical Data: Biaxial (-), a=1.703, b=1.744, g=1.786, bire=0.0830, 2V(Calc)=88, 2V(Meas)=85. Dispersion r < v.
Help on Pleochroism (x): Pleochroism (x): very pale green.
Help on Pleochroism (y): Pleochroism (y): pale green.
Help on Pleochroism (z): Pleochroism (z): green.

Calculated Properties of Ahlfeldite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.36 gm/cc
note: Specific Gravity of Ahlfeldite =3.52 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.02
Boson Index = 0.98
Help on Photoelectric: Photoelectric: PEAhlfeldite = 36.69 barns/electron
U=PEAhlfeldite x rElectron Density= 123.20 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Ahlfeldite is Not Radioactive

Ahlfeldite Classification

Help on  Dana Class: Dana Class: (34)Selenites - Tellurites - Sulfites
  (34.02)as A++ XO3 � x(H2O)
  (34.02.03)Chalcomenite Group (Monoclinic) Clinochalcomenite CuSeO3•2(H2O) P 21/n 2/m Cobaltomenite CoSeO3•2(H2O) P 21/n 2/m Ahlfeldite (Ni,Co)SeO3•2(H2O) P 21/m 2/m
Help on  Strunz Class: Strunz Class: 04.JH.10 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate
  04.J - Arsenites, Antimonites, Bismuthites, Sulfites,
  04.JH -Selenites without additional anions, with H2O
04.JH.10 Ahlfeldite (Ni,Co)SeO3•2(H2O) P 21/m 2/m
04.JH.10 Clinochalcomenite CuSeO3•2(H2O) P 21/n 2/m
04.JH.10 Cobaltomenite CoSeO3•2(H2O) P 21/n 2/m

Other Ahlfeldite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)
Help on See Also: See Also: Links to other databases for Ahlfeldite :
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: 04.JH.10





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