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About LecontiteHide

John Lawrence LeConte
(NH4,K)NaSO4 · 2H2O
Colourless; colourless in transmitted light
2 - 2½
Specific Gravity:
Crystal System:
After John L. LeConte (New York City 13 May 1825 - Philadelphia 15 November 1883), American entomologist, discoverer of the species.
This page provides mineralogical data about Lecontite.

Classification of LecontiteHide

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

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
D : With only large cations

2 : A2XO4·xH2O

Physical Properties of LecontiteHide

Colourless; colourless in transmitted light
2 - 2½ on Mohs scale
1.745 g/cm3 (Measured)    1.747 g/cm3 (Calculated)

Optical Data of LecontiteHide

Biaxial (-)
RI values:
nα = 1.440 nβ = 1.454 nγ = 1.455
Measured: 40° to 43°, Calculated: 28°
Max Birefringence:
δ = 0.015
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 LecontiteHide

(NH4,K)NaSO4 · 2H2O
IMA Formula:
(NH4)Na(SO4) · 2H2O

Crystallography of LecontiteHide

Crystal System:
Class (H-M):
2 2 2 - Disphenoidal
Space Group:
P21 21 21
Cell Parameters:
a = 8.216(8) Å, b = 12.854(1) Å, c = 6.232(8) Å
a:b:c = 0.639 : 1 : 0.485
Unit Cell V:
658.15 ų (Calculated from Unit Cell)
Thin prismatic crystals; also very short and wide, very fine grained masses.

Crystal StructureHide

Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0009882LecontiteArzt S, Glazer A M (1994) The optical activity and absolute optical chirality of NaNH4SO4*2H2O Acta Crystallographica B50 425-4311994synthetic0293
CIF Raw Data - click here to close

Geological EnvironmentHide

Geological Setting:
Early breakdown product of bat guanno

Type Occurrence of LecontiteHide

Place of Conservation of Type Material:
Yale University
Geological Setting of Type Material:

Other Language Names for LecontiteHide


Common AssociatesHide


Related Minerals - Nickel-Strunz GroupingHide

7.CD.Argesite(NH4)7Bi3Cl16Trig. 3m (3 2/m) : R3c
7.CD.Campostriniite(Bi3+,Na)3(NH4,K)2Na2(SO4)6·H2OMon. 2/m : B2/b
7.CD.05MatteucciteNaHSO4 · H2OMon.
7.CD.10MirabiliteNa2SO4 · 10H2OMon. 2/m
7.CD.20HydroglauberiteNa10Ca3(SO4)8 · 6H2OMon.
7.CD.25EugsteriteNa4Ca(SO4)3 · 2H2OMon.
7.CD.30GörgeyiteK2Ca5(SO4)6 · H2OMon.
7.CD.35Koktaite(NH4)2Ca(SO4)2 · H2OMon.
7.CD.35SyngeniteK2Ca(SO4)2 · H2OMon. 2/m : P21/m
7.CD.40GypsumCaSO4 · 2H2OMon. 2/m
7.CD.45BassaniteCa(SO4) · 0.5H2OMon. 2 : B2
7.CD.50Zircosulfate(Zr,Ti)(SO4)2 · 4H2OOrth.
7.CD.55SchieffelinitePb10Te6+6O20(OH)14(SO4)(H2O)5Orth. mmm (2/m 2/m 2/m) : Cmcm
7.CD.60MontaniteBi2(TeO6) · 2H2O
7.CD.65OmongwaiteNa2Ca5(SO4)6 · 3H2OMon. 2 : B2

Other InformationHide

Taste bitter, salty
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 LecontiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Taylor (1858) American Journal of Science: 26: 273.
Dawson (1918) Journal of the Chemical Society of London: 113: 675.
Larsen, E.S. (1921) The Microscopic Determination of the Nonopaque Minerals, First edition, USGS Bulletin 679: 99.
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. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged: 438-439.
American Mineralogist (1963): 48: 180.
Acta Crystallographica (1967): 22: 683-687.

Internet Links for LecontiteHide

Localities for LecontiteHide

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.
  • Antofagasta
    • Antofagasta Province
      • Estación La Negra
      • Mejillones
        • Mejillones peninsula
    • El Loa Province
      • Calama
        • Chuquicamata District
James A. Bauer Collection
  • Hauts-de-France
    • Pas-de-Calais
      • Lens
Naze-Nancy Masalehdani, M., Mees, F., Dubois, M., Coquinot, Y., Potdevin, J.-L., Fialin, M. & Blanc-Valleron, M.-M. (2009): Condensate minerals from a burning coal-waste heap in Avion, Northern France. Can. Mineral. 47, 573-591.
Honduras (TL)
  • La Paz Department
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: 439; American Mineralogist (1963): 48: 180; J.W. Anthony, R.A. Bideaux, K.W. Bladh, M.C. Nichols: Handbook of Mineralogy, Vol. V (2003)
  • Stockholm County
    • Stockholm
Jalilehvand, F., Sandstrom, M., Persson, I., Gelius, U., & Frank, P. (2001). Acidity and Salt Precipitation on the Vasa; The Sulfur Problem. Proceedings 8th ICOM-CC WO AM Conference Stockholm 11-15 June 2001
  • California
    • Imperial Co.
      • Salton Sea
        • Mullet Island
Adams, P., & Lynch, D. (2014). A mineralogical inventory of geothermal features southeast of the Salton Sea, Imperial County, California. Trough to trough: The Colorado River and the Salton Sea (Reynolds, R, 39-43.
Adams, P., & Lynch, D. (2014). A mineralogical inventory of geothermal features southeast of the Salton Sea, Imperial County, California. Trough to trough: The Colorado River and the Salton Sea (Reynolds, R, 39-43.
  • Nevada
    • Washoe Co.
NBMG Spec. Pub. 31 Minerals of Nevada
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