Mineralogy Database

Gahnite Mineral Data

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General Gahnite Information

Help on Chemical  Formula: Chemical Formula: ZnAl2O4
Help on Composition: Composition: Molecular Weight = 183.35 gm
   Aluminum  29.43 %  Al   55.61 % Al2O3
   Zinc      35.66 %  Zn   44.39 % ZnO
   Oxygen    34.90 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: ZnAl2O4
Help on Environment: Environment: Metamorphic and pegmatitic rocks.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1807
Help on Locality: Locality: Falun, Sweden. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after the Swedish chemist and mineralogist, J. G. Gahn (1745-1818).
Help on Name Pronunciation: Name Pronunciation: Gahnite Say GAHNITE
Help on Synonym: Synonym: ICSD 9559
  PDF 5-669
  Zinc Spinal
 

Gahnite Image

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  Gahnite

Comments: Deep blue octahedral crystals of gahnite in quartz.
Location: Franklin, Sussex County, New Jersey, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

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  Gahnite

Comments: Optical micrograph of gahnite (blue) + Na-Ca-Li mica pseudomorph after staurolite in calcite matrix pigmented with brownish Fe-(hydr)oxide. (AmMin, 88:794).
Location: Diaspore-bearing metabauxite from East Samos (Greece). Scale: See Image.
© American Mineralogist

Gahnite Crystallography

Help on Cell Dimensions: Cell Dimensions: a = 8.062, Z = 8; V = 524.00 Den(Calc)= 4.65
Help on Crystal System: Crystal System: Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F d3m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.438(1), 2.861(0.84), 1.429(0.43),
Help on Forms: Forms:

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Forms: ( 0 1 1) ( 1 1 1) ( 1 0 0)

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Physical Properties of Gahnite

Help on Cleavage: Cleavage: {111} Indistinct
Help on Color: Color: Bluish green, Grayish green, Deep leek green, Greenish black, Bluish black.
Help on Density: Density: 4 - 4.6, Average = 4.3
Help on Diaphaneity: Diaphaneity: Subtransparent to opaque
Help on Fracture: Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Help on Habit: Habit: Euhedral Crystals - Occurs as well-formed crystals showing good external form.
Help on Habit: Habit: Massive - Granular - Common texture observed in granite and other igneous rock.
Help on Habit: Habit: Striated - Parallel lines on crystal surface or cleavage face.
Help on Hardness: Hardness: 8 - Topaz
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Vitreous (Glassy)
Help on Magnetism: Magnetism: Nonmagnetic
Help on Streak: Streak: gray
 

Optical Properties of Gahnite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.029 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.048 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1763,KPDmeas= 0.1907,KC= 0.1852
Ncalc = 1.74 - 1.86
Help on Optical Data: Optical Data: Isotropic, n=1.82.
 

Calculated Properties of Gahnite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=4.13 gm/cc
note: Specific Gravity of Gahnite =4.30 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEGahnite = 18.63 barns/electron
U=PEGahnite x rElectron Density= 76.89 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Gahnite is Not Radioactive
 

Gahnite Classification

Help on  Dana Class: Dana Class: 07.02.01.04 (07)Multiple Oxides
  (07.02)(A+ B++)2 X4 Spinel group
  (07.02.01)(Aluminum subgroup)
 
07.02.01.01 Spinel MgAl2O4 F d3m 4/m 3 2/m
 
07.02.01.02 Galaxite (Mn,Mg)(Al,Fe)2O4 F d3m 4/m 3 2/m
 
07.02.01.03 Hercynite FeAl2O4 F d3m 4/m 3 2/m
 
07.02.01.04 Gahnite ZnAl2O4 F d3m 4/m 3 2/m
Help on  Strunz Class: Strunz Class: 04.BB.05 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate
  04.B - Metal:Oxygen = 3:4 and similar
  04.BB -With only medium-sized cations
 
04.BB.05 Cochromite (Co,Ni,Fe)(Cr,Al)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Filipstadite (Mn,Mg)4SbFeO8 pseudo ISO 2/m 2/m 2/m
 
04.BB.05 Magnetite FeFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Gahnite ZnAl2O4 F d3m 4/m 3 2/m
 
04.BB.05 Chromite FeCr2O4 F d3m 4/m 3 2/m
 
04.BB.05 Galaxite (Mn,Mg)(Al,Fe)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Cuprospinel (Cu,Mg)Fe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Donathite? (Fe,Mg)(Cr,Fe)2O4 P 4/nnm 4/m 2/m 2/m
 
04.BB.05 Brunogeierite (Ge,Fe)Fe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Coulsonite FeV2O4 F d3m 4/m 3 2/m
 
04.BB.05 Hercynite FeAl2O4 F d3m 4/m 3 2/m
 
04.BB.05 Franklinite (Zn,Mn,Fe)(Fe,Mn)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Jacobsite (Mn,Fe,Mg)(Fe,Mn)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Magnesiochromite MgCr2O4 F d3m 4/m 3 2/m
 
04.BB.05 Magnesioferrite MgFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Magnesiocoulsonite MgV2O4 F d3m 4/m 3 2/m
 
04.BB.05 Manganochromite (Mn,Fe)(Cr,V)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Qandilite (Mg,Fe)2(Ti,Fe,Al)O4 F d3m 4/m 3 2/m
 
04.BB.05 Nichromite (Ni,Co,Fe)(Cr,Fe,Al)2O4 F d3m 4/m 3 2/m
 
04.BB.05 Spinel MgAl2O4 F d3m 4/m 3 2/m
 
04.BB.05 Ulvospinel TiFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Zincochromite ZnCr2O4 F d3m 4/m 3 2/m
 
04.BB.05 Trevorite NiFe2O4 F d3m 4/m 3 2/m
 
04.BB.05 Vuorelainenite (Mn,Fe)(V,Cr)2O4 F d3m 4/m 3 2/m
 

Other Gahnite Information

Help on References: References: NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)
Help on See Also: See Also: Links to other databases for Gahnite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - CalTech Mineral Spectroscopy
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - Franklin Minerals(Dunn)
8 - Franklin Minerals(Palache)
9 - GeoScienceWorld
10 - Google Images
11 - Google Scholar
12 - Handbook of Mineralogy (MinSocAm)
13 - Handbook of Mineralogy (UofA)
14 - MinDAT
15 - Mineralienatlas (Deutsch)
16 - Online Mineral Museum
17 - QUT Mineral Atlas
18 - Ruff.Info
19 - Scandinavian mineral gallery
20 - WWW-MINCRYST

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

Gahnite

ZnAl2O4
Dana No: 07.02.01.04 Strunz No: 04.BB.05
Locality:

 

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