Donate now to keep alive!Help|Log In|Register|
Home PageMindat NewsThe Mindat ManualHistory of MindatCopyright StatusManagement TeamContact UsAdvertise on Mindat
Donate to MindatSponsor a PageSponsored PagesTop Available PagesMindat AdvertisersAdvertise on Mindat
What is a mineral?The most common minerals on earthMineral PhotographyThe Elements and their MineralsGeological TimeMineral Evolution
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
StatisticsThe ElementsMember ListBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery


This page is currently not sponsored. Click here to sponsor this page.
(NH4)2(C2O4) · H2O
Colourless to pale yellow; colourless in transmitted light.
Specific Gravity:
Crystal System:
In allusion to the composition, containing both OXalate and AMMonium ions.
An organic mineral derived from guano; in sub-fossil bird eggs and on sub-fossil birds.

Hide all sections | Show all sections

Classification of OxammiteHide

Approved, 'Grandfathered' (first described prior to 1959)

A : Salts of organic acids
B : Oxalates

1 : Oxalates

31 : Oxalates, Citrates, Mellitates and Acetates
1 : Oxalates

Physical Properties of OxammiteHide

Transparent, Opaque
Colourless to pale yellow; colourless in transmitted light.
2½ on Mohs scale
On {001},distinct.
1.5 g/cm3 (Measured)    1.541 g/cm3 (Calculated)

Optical Data of OxammiteHide

Biaxial (-)
RI values:
nα = 1.438 nβ = 1.547 nγ = 1.595
Measured: 62° , Calculated: 62°
Max Birefringence:
δ = 0.157
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
dispersion not observed

Chemical Properties of OxammiteHide

(NH4)2(C2O4) · H2O
IMA Formula:
(NH4)2C2O4 · H2O

Crystallography of OxammiteHide

Crystal System:
Class (H-M):
2 2 2 - Disphenoidal
Space Group:
P21 21 2
Cell Parameters:
a = 8.035 Å, b = 10.32 Å, c = 3.801 Å
a:b:c = 0.779 : 1 : 0.368
Unit Cell V:
315.18 ų (Calculated from Unit Cell)
Crystals rare; commonly occurs as lamellar or pulverulent masses. Artificial crystals are spenoidal in form

Type Occurrence of OxammiteHide

Place of Conservation of Type Material:
Yale University, New Haven, Connecticut, USA.
Geological Setting of Type Material:
Bird guano deposit
Associated Minerals at Type Locality:

Synonyms of OxammiteHide

Other Language Names for OxammiteHide

Related Minerals - Nickel-Strunz GroupingHide

10.AB.05HumboldtineFe2+(C2O4) · 2H2OMon. 2/m
10.AB.05LindbergiteMn2+(C2O4) · 2H2OMon. 2/m
10.AB.10GlushinskiteMg(C2O4) · 2H2OMon.
10.AB.15MoolooiteCu(C2O4) · 0.4H2OOrth.
10.AB.20StepanoviteNaMgFe3+(C2O4)3 · 8-9H2OTrig. 3m : P3c1
10.AB.25MinguzziteK3Fe3+(C2O4)3 · 3H2OMon. 2/m : P21/b
10.AB.30WheatleyiteNa2Cu(C2O4)2 · 2H2OTric.
10.AB.35ZhemchuzhnikoviteNaMgAl(C2O4)3 · 8H2OTrig. 3m : P3c1
10.AB.40WeddelliteCa(C2O4) · (2.5-x)H2OTet. 4/m : I4/m
10.AB.45WhewelliteCa(C2O4) · H2OMon. 2/m : P21/b
10.AB.50CaoxiteCa(C2O4) · 3H2OTric.
10.AB.65Coskrenite-(Ce)(Ce,Nd,La)2(C2O4)(SO4)2 · 12H2OTric.
10.AB.70Levinsonite-(Y)(Y,Nd,La)Al(C2O4)(SO4)2 · 12H2OMon. 2/m
10.AB.75Zugshunstite-(Ce)(Ce,Nd,La)Al(C2O4)(SO4)2 · 12H2OMon.
10.AB.80NovgorodovaiteCa2(C2O4)Cl2 · 2H2OMon. 2/m

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

31.1.2MoolooiteCu(C2O4) · 0.4H2OOrth.
31.1.3WheatleyiteNa2Cu(C2O4)2 · 2H2OTric.
31.1.4GlushinskiteMg(C2O4) · 2H2OMon.
31.1.5WhewelliteCa(C2O4) · H2OMon. 2/m : P21/b
31.1.6WeddelliteCa(C2O4) · (2.5-x)H2OTet. 4/m : I4/m
31.1.7HumboldtineFe2+(C2O4) · 2H2OMon. 2/m
31.1.8StepanoviteNaMgFe3+(C2O4)3 · 8-9H2OTrig. 3m : P3c1
31.1.9ZhemchuzhnikoviteNaMgAl(C2O4)3 · 8H2OTrig. 3m : P3c1
31.1.10MinguzziteK3Fe3+(C2O4)3 · 3H2OMon. 2/m : P21/b

Other InformationHide

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

References for OxammiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Brio (1867) Konigliche Akademie der Wissenschaften, Vienna, Sitzber.: 55: 870.
Shepard (1870) Rural Carolinian: 1: 471 (May, 1870).
Tanner (1875) Chemical News and Journal of Industrial Science, London: 32: 162.
Raimondi, A. (1878) Minéraux du Pérou: Catalogue raisonné d’une collection des principaux types minéraux de la République. 336pp., Paris.: 30, 33 (as Guañapite).
Groth, P. (1910) Chemische Krystallographie. Leipzig. 5 volumes: vol. 3: 150.
Frondel, C. (1950) Notes on arcanite, ammonian aphthitalite and arcanite. American Mineralogist, 35, 596–598.
Palache, Charles, Harry Berman & Clifford Frondel (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume II. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged, 1124 pp.: 1103-1104.
Winchell, H. and R.J. Benoit (1951) Taylorite, mascagnite, aphthitalite, lecontite, and oxammite from guano. American Mineralogist, 36, 590–601.
National Bureau of Standards Circular 539 (1957), 7, 5.
Taylor, J.C. and T.M. Sabine (1972) Isotope and bonding effects in ammonium oxalate monohydrate, determined by the combined use of neutron and X-ray diffraction analyses. Acta Crystallographica (1972): B28: 3340-3351.

Internet Links for OxammiteHide

Localities for OxammiteHide

This 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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
  • Western Australia
    • Dundas Shire
      • Madura Roadhouse
Mineralogical Magazine (1977): 41: 33-35.
Peru (TL)
  • La Libertad Department
    • Virù Province
American Mineralogist (1951): 36: 590; Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 1104.
Mineral and/or Locality is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © and the Hudson Institute of Mineralogy 1993-2018, except where stated. relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: January 17, 2018 20:28:31 Page generated: January 9, 2018 14:31:34
Go to top of page