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Na2[B4O6(OH)2] · 3H2O
Colourless to white.
Specific Gravity:
Crystal System:
After Kern County, California, USA, where it was first discovered.
This page provides mineralogical data about Kernite.

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Classification of KerniteHide

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

D : Tetraborates
B : Ino-tetraborates

4 : Tetraborates

9 : Borates
1 : Borates of the alkalis and boric acid

Physical Properties of KerniteHide

Satinly on fibrous cleavages
Colourless to white.
2½ on Mohs scale
On {100} perfect; {001} less perfect; on {201} fair. NOTE: The cleavable masses exhibit a simulated fibrous structure due to development of excellent cleavages. Cleavage fragments usually bent or warped around [001].
1.906(3) g/cm3 (Measured)    1.905 g/cm3 (Calculated)

Optical Data of KerniteHide

Biaxial (-)
RI values:
nα = 1.454 nβ = 1.472 nγ = 1.488
Measured: 80° , Calculated: 84°
Max Birefringence:
δ = 0.034
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
r > v distinct

Chemical Properties of KerniteHide

Na2[B4O6(OH)2] · 3H2O
IMA Formula:
Na2B4O6(OH)2 · 3H2O

Crystallography of KerniteHide

Crystal System:
Class (H-M):
2/m - Prismatic
Space Group:
Cell Parameters:
a = 7.0172(2) Å, b = 9.1582(2) Å, c = 15.6774(5) Å
β = 108.861(2)°
a:b:c = 0.766 : 1 : 1.712
Unit Cell V:
953.41 ų (Calculated from Unit Cell)
Crystals nearly equant, commonly slightly elongated [100] and deeply striated [010], with irregular form development. Wedge-shaped at times or rounded due to repetition of faces. Cleavable masses. Massive.
On {011}.

X-Ray Powder DiffractionHide

Image Loading

Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Type Occurrence of KerniteHide

Geological Setting of Type Material:
Metamorphosed bedded borate deposit in clay-shales.
Associated Minerals at Type Locality:

Synonyms of KerniteHide

Other Language Names for KerniteHide

Common AssociatesHide

Associated Minerals Based on Photo Data:
Gerstleyite4 photos of Kernite associated with Gerstleyite on
Realgar3 photos of Kernite associated with Realgar on
Tincalconite3 photos of Kernite associated with Tincalconite on

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

9.1.1SassoliteH3BO3Tric. 1 : P1
9.1.4BiringucciteNa2B5O8(OH) · H2OMon.
9.1.5NasiniteNa2[B5O8(OH)] · 2H2OOrth.
9.1.7EzcurriteNa4B10O17 · 7H2OTric. 1 : P1
9.1.8TincalconiteNa2(B4O7) · 5H2OTrig. 3 2 : R3 2
9.1.9BoraxNa2(B4O5)(OH)4 · 8H2OMon. 2/m : B2/b
9.1.11SborgiteNa[B5O6(OH)4] · 3H2OMon.
9.1.12AristarainiteNa2MgB12O20 · 8H2OMon. 2/m : P21/b
9.1.13SantiteK[B5O6(OH)4] · 2H2OOrth.
9.1.14Larderellite(NH4)B5O7(OH)2 · H2OMon.
9.1.15Ammonioborite(NH4)2[B5O6(OH)4]2 · H2OMon. 2/m : B2/b
9.1.16Rhodizite(K,Cs)Al4Be4(B,Be)12O28Iso. 4 3m : P4 3m

Other InformationHide

Thermal Behaviour:
Alters to metakernite (Na2B4O7·5H2O) upon heating to 100° - 120° C, as a non-reversible change.
Slowly soluble in cold water, readily so in hot water.

Alters to tincalconite upon dehydration.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Kernite in petrologyHide

An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.

References for KerniteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Palmer (1927) Engineering and Mining Journal: 123: 494 (as rasorite).
Schaller, W.T. (1927) Kernite, a new sodium borate. American Mineralogist: 12: 24-25.
Schaller (1930) Borate Minerals from the Kramer District, Mohave Desert, California. U.S. Geological Survey Professional Paper: 158: 137-170.
Foshag, W.F. (1930) New mineral names. American Mineralogist: 15: 274-276.
Garrido, J. (1932) Symmetrie und Raumgruppe des Kernits. Zeitschr. Kristallographie, band 82: 468-470.
Minder (1935) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 92: 301.
Minder, Schulz and Deckert (1935) Die Naturwissenschaften, Berlin: 23: 832.
Schaller, W.T. (1936) The origin of kernite and borax in the Kramer borate field, California (abstract). American Mineralogist: 21: 192.
Menzel and Schulz (1940) Zeitschrift für anorganische und allgemeine Chemie, Hamburg, Leipzig: 245: 157.
Amorós (1947) Inst. Invest. Geol. Barcelona, no. 7.
Palache, C., Berman, H., and 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: 335-337.
Muessig, S. and Allen, R.D. (1957) The hydration of kernite (Na3B4O7·4H2O). American Mineralogist: 42: 699-701.
American Mineralogist (1973) 58: 21-31.
Grew, E.S. and Anovitz, L.M. (1996) BORON: Mineralogy, Petrology and Geochemistry, second edition, as revised (2002).
Anthony, J.W., Bideaux, R.A., Bladh, K.W., and Nichols, M.C. (2003) Handbook of Mineralogy, Volume V. Borates, Carbonates, Sulfates. Mineral Data Publishing, Tucson, AZ, 813pp.: 352.

Internet Links for KerniteHide

Localities for KerniteHide

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.
  • Eastern Antarctica
    • Transantarctic Mts
      • Buckley Island quadrangle
Fitzpatrick, J.J., Muhs, D.R. (1990) Antarctic Journal of the United States, 24 (5), 63-65.
  • Salta
    • Los Andes department
      • Salar del Hombre Muerto
Am Min 58:308-313; Alonso, R. N. (1999). On the origin of La Puna borates. Acta geológica hispánica, 34(2), 141-166.; CAHIT HELVACI & RICARDO N. ALONSO (2000) Borate Deposits of Turkey and Argentina; A Summary and Geological Comparison. Turkish Journal of Earth Sciences, 9:1-27.
Kezao Chen (1992): Quaternary Sciences 3(8), 193-202
  • Central Anatolia Region
    • Eskişehir Province
      • Kirka
CAHIT HELVACI & RICARDO N. ALONSO (2000) Borate Deposits of Turkey and Argentina; A Summary and Geological Comparison. Turkish Journal of Earth Sciences, Vol. 9, 2000, pp. 1-27
  • California
    • Kern Co.
      • Kramer District (Kramer Borate District)
Rock Currier collection
Schaller, Waldemar Theodore (1927), Kernite, a new sodium borate: American Mineralogist: 12: 24; Eakle, Arthur Starr (1929), Probertite, a new borate: American Mineralogist: 14: 427; Morgan, V. and Erd, R.C. (1969) Minerals of the Kramer borate district, California California Division of Mines and Geology Mineral Information Service: 22(9): 147-148, 153, 169; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 259.
Meier, D. C., Davis, J. M., & Vicenzi, E. P. (2011). An examination of kernite (Na 2 B 4 O 6 (OH) 2· 3H 2 O) using X-ray and electron spectroscopies: quantitative microanalysis of a hydrated low-z mineral. Microscopy and Microanalysis, 17(05), 718-727.
Frondel C, Morgan V (1956) Inderite and gerstleyite from the Kramer borate district, Kern County, California. American Mineralogist 41, 839-843
Boslough, M. B., Weldon, R. J., & Ahrens, T. J. (1980). Impact-induced water loss from serpentine, nontronite and kernite. In Lunar and Planetary Science Conference Proceedings (Vol. 11).
            • West Baker
Am Min 49:543-555
        • Rich
American Mineralogist (1927): 12: 24-25.
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