Mindat Logo
Home Page Log In Message Board The Mindat Directory
Register Search Pages Chat Now! (6 online) Mindat Auctions

Gahnite

Big Photo

Franklin, Franklin Mining District, Sussex Co., New Jersey, USA
© Rob Lavinsky

Show Gahnite Photos (31)
Formula:
ZnAl
 
2
O
 
4
System:IsometricColour:Dark blue-green, yellow, ...
Lustre:VitreousHardness:7½ - 8
Name:For Swedish chemist and mineralogist, Johan Gottlieb Gahn (1745-1818).


Spinel Group, Al series. Gahnite-Hercynite Series, and the Gahnite-Spinel Series.

Classification of Gahnite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:4/B.01-40
Nickel-Strunz 10th (pending) edition ID:4.BB.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
B : Metal: Oxygen = 3:4 and similar
B : With only medium-sized cations
Dana 8th edition ID:7.2.1.4

7 : MULTIPLE OXIDES
2 : AB2X4
Hey's CIM Ref.:7.5.5

7 : Oxides and Hydroxides
5 : Oxides of Zn, Cd and Hg
mindat.org URL:http://www.mindat.org/min-1632.html
Please feel free to link to this page.

Type Occurrence of Gahnite

Type Locality:Falu mine, Falun, Dalarna, Sweden
Year of Discovery:1807

Physical Properties of Gahnite

Lustre:Vitreous
Colour:Dark blue-green, yellow, brown, black
Streak:Grey
Hardness (Mohs):7½ - 8
Tenacity:Brittle
Fracture:Irregular/Uneven, Conchoidal
Density (calculated):4.62 g/cm3

Crystallography of Gahnite

Crystal System:Isometric
Class (H-M):m3m (4/m 3 2/m) - Hexoctahedral
Space Group:Fd3m (F41/d 3 2/m)
Cell Parameters:a = 8.062Å
Unit Cell Volume:V 524.00 ų (Calculated from Unit Cell)
Morphology:Crystals usually octahedral.
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data: Peaks:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Gahnite

Type:Isotropic

Chemical Properties of Gahnite

Formula:
ZnAl
 
2
O
 
4
Essential elements:Al, O, Zn
All elements listed in formula:Al, O, Zn
Common Impurities:Fe,Mg

Relationship of Gahnite to other Species

Series:Forms a series with Spinel (see here)
Forms a series with Hercynite (see here)
Related Minerals - Nickel-Strunz Grouping):
4.BB.05Brunogeierite
(Ge,Fe)Fe
 
2
O
 
4
4.BB.05Chromite
FeCr
 
2
O
 
4
4.BB.05Cochromite
(Co,Ni,Fe)(Cr,Al)
 
2
O
 
4
4.BB.05Coulsonite
FeV
 
2
O
 
4
4.BB.05Cuprospinel
Cu
2+
 
Fe
3+
2
O
 
4
4.BB.05Filipstadite
(Mn,Mg)
 
2
(Sb
 
.5
Fe
 
.5
)O
 
4
4.BB.05Franklinite
Zn
2+
 
Fe
3+
2
O
 
4
4.BB.05Galaxite
(Mn,Fe,Mg)(Al,Fe)
 
2
O
 
4
4.BB.05Hercynite
FeAl
 
2
O
 
4
4.BB.05Jacobsite
Mn
2+
 
Fe
3+
2
O
 
4
4.BB.05Manganochromite
(Mn,Fe)(Cr,V)
 
2
O
 
4
4.BB.05Magnesiocoulsonite
MgV
 
2
O
 
4
4.BB.05Magnesiochromite
MgCr
 
2
O
 
4
4.BB.05Magnesioferrite
MgFe
3+
2
O
 
4
4.BB.05Magnetite
Fe
2+
 
Fe
3+
2
O
 
4
4.BB.05Nichromite
(Ni,Co,Fe)(Cr,Fe,Al)
 
2
O
 
4
4.BB.05Qandilite
(Mg,Fe)
 
2
(Ti,Fe,Al)O
 
4
4.BB.05Spinel
MgAl
 
2
O
 
4
4.BB.05Trevorite
Ni
2+
 
Fe
3+
2
O
 
4
4.BB.05Ulvöspinel
Fe
 
2
TiO
 
4
4.BB.05Vuorelainenite
(Mn,Fe)(V,Cr)
 
2
O
 
4
4.BB.05Zincochromite
ZnCr
 
2
O
 
4
4.BB.05Tegengrenite
(Mg,Mn
2+
 
)
 
2
Sb
5+
0.5
(Mn
3+
 
,Si,Ti)
 
0.5
O
 
4
4.BB.10Hausmannite
MnMn
 
2
O
 
4
4.BB.10Hetaerolite
ZnMn
 
2
O
 
4
4.BB.10Hydrohetaerolite
ZnMn
 
2
O
 
4
·H
 
2
O
4.BB.10Iwakiite
Mn(Fe,Mn)
 
2
O
 
4
4.BB.15Maghemite
Fe
 
2
O
 
3
4.BB.15Titanomaghemite
Fe
3+
 
(Fe
3+
 
,Ti
4+
 
,Fe
2+
 
,[])
 
2
O
 
4
Related Minerals - Hey's Index Grouping:
7.5.1Zincite
(Zn,Mn
2+
 
,Fe
2+
 
)O
7.5.2Sweetite
Zn(OH)
 
2
7.5.3Ashoverite
Zn(OH)
 
2
7.5.4Wülfingite
Zn(OH)
 
2
7.5.6Hetaerolite
ZnMn
 
2
O
 
4
7.5.7Hydrohetaerolite
ZnMn
 
2
O
 
4
·H
 
2
O
7.5.8Chalcophanite
(Zn,Fe,Mn)Mn
 
3
O
 
7
·3H
 
2
O
7.5.9Woodruffite
Zn(Mn
4+
 
,Mn
3+
 
)
 
5
O
 
10
·3½H
 
2
O
7.5.10Franklinite
Zn
2+
 
Fe
3+
2
O
 
4
7.5.11Monteponite
CdO
7.5.12Montroydite
HgO

Other Names for Gahnite

Synonyms:
AutomaliteAutomoliteDysluiteFahlunite (of Karsten)Gahnite (of von Moll)
Spinellus superiusZinc Spinel
French names:
Spinelle Zincifère
German names:
AutomalitAutomolitGahnitZinkspinell
Russian names:
Ганит
Spanish names:
AutomalitaAutomolitaGahnita
Varieties:
KreittoniteLimaiteManganoan Gahnite

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Gahnite

Reference List:Palache, Charles, Harry Berman & Clifford Frondel (1944), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Seventh edition, Volume I: 689-697.

Mineralogical Magazine: 62: 41-54.

Spry, P.G. (1987) Compositional zoning in zincian spinel. Canadian Mineralogist: 25: 97-104.

Waerenborgh, J.C., Annersten, H., Ericsson, T., Figueiredo, M.O., and Cabral, J.M.P. (1990) A Mössbauer study of natural gahnite spinels showing strongly temperature dependent quadrupole splitting distributions. European Journal of Mineralogy: 2: 267-271.

O'Neill, H.St.C. and Dollase, W.A. (1994) Crystal structures and cation distribution in simple spinels from powder XRD structural refinements: MgCr2O4, ZnCr2O4, Fe3O4, and the temperature dependence of the cation distribution in ZnAl2O4. Physics and Chemistry of Minerals: 20: 541-555.

Internet Links for Gahnite

Search Engines:
  • Look for Gahnite on Google
  • Look for Gahnite images on Google
    • External Links:
  • Look for Gahnite on Webmineral
  • Look for Gahnite on Athena Mineralogy
  • Look for Gahnite on Wikipedia
  • Look for Gahnite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Gahnite in the Natural History Museum (London) online catalogue
  • Gahnite details from Handbook of Mineralogy (PDF)
    • Mineral Dealers:
  • Buy Minerals and Crystals from Crystalarium.com
  • Wendel Minerals - Auktion & Shop
  • Wright's Rock Shop - excellent mineral specimens since 1970
  • rare and unusual minerals mainly crystallized
  • Search for Gahnite at Thames Valley Minerals
  • Rare and Unusual minerals at Mineralogical Research Company
  • Top quality minerals from Kristalle of California
  • Find Gahnite on www.crystalclassics.co.uk
  • Lapis Mineral Magazin
  • e-Rocks - Mineral Auctions and Sales
  • High-end worldwide specimens & outstanding customer service
  • Buy Fine Minerals from mineralsweb.com
    • Jobs:
  • Mining & Geology Jobs

    • Page Sponsor

    Sponsorship:This page is currently not sponsored. Click here to find out how you can sponsor this page.

    Localities for Gahnite

    Show Locality List (259 Items)
    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    These maps work faster with Firefox!
    Mineral and/or Locality
    Google
     
    www.mindat.org Web
    Copyright © Jolyon & Ida Ralph 1993-2008. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. If you would like to add information to improve the quality of our database, then click here to register.