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Kernite
A valid IMA mineral species - grandfathered
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About Kernite
Seal of Kern County, California, USA
Formula:
Na2[B4O6(OH)2] · 3H2O
Colour:
Colourless to white
Lustre:
Vitreous
Hardness:
2½
Specific Gravity:
1.906
Crystal System:
Monoclinic
Name:
After Kern County, California, USA, where it was first discovered.
Type Locality:
This page provides mineralogical data about Kernite.
Unique Identifiers
Mindat ID:
2188
Long-form identifier:
mindat:1:1:2188:9
Similar Names
| Corneite | A synonym of 'Biotite hornfels' | |
| Cornite | A synonym of 'Petrosilex' | |
| Cornuite (of Rogers) | A variety of Chrysocolla | Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O |
| Coronite | A rock subtype | |
| Coronite (of Hunt) | A synonym of Dravite | |
| Corynite | A synonym of 'Antimony-bearing Gersdorffite' | |
| Ernite | A synonym of Grossular | |
| Granite | A rock classification type | |
| Guérinite | A valid IMA mineral species - grandfathered | Ca6(HAsO4)3(AsO4)2 · 10.5H2O |
| Kerite | ||
| Kerrite | A synonym of Vermiculite | |
| Kornite | A synonym of Potassic-mangani-leakeite | |
| Kornite (of Frenzel) | A rock subtype |
IMA Classification of Kernite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Na2B4O6(OH)2·3H2O
First published:
1927
Classification of Kernite
6.DB.05
6 : BORATES
D : Tetraborates
B : Ino-tetraborates
6 : BORATES
D : Tetraborates
B : Ino-tetraborates
26.4.5.1
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
4 : Tetraborates
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
4 : Tetraborates
9.1.6
9 : Borates
1 : Borates of the alkalis and boric acid
9 : Borates
1 : Borates of the alkalis and boric acid
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Ker | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Kernite
Vitreous
Transparency:
Transparent
Comment:
Satinly on fibrous cleavages
Colour:
Colourless to white
Streak:
White
Hardness:
2½ on Mohs scale
Tenacity:
Flexible
Cleavage:
Perfect
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].
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].
Fracture:
Splintery
Density:
1.906(3) g/cm3 (Measured) 1.905 g/cm3 (Calculated)
Optical Data of Kernite
Type:
Biaxial (-)
RI values:
nα = 1.454 nβ = 1.472 nγ = 1.488
2V:
Measured: 80° , Calculated: 84°
Max. Birefringence:
δ = 0.034
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate (negative)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r > v distinct
Optical Extinction:
Z = b; X ∧ c = 70.5°.
Chemistry of Kernite
Mindat Formula:
Na2[B4O6(OH)2] · 3H2O
Element Weights:
Elements listed:
Crystallography of Kernite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P2/b
Cell Parameters:
a = 7.0172(2) Å, b = 9.1582(2) Å, c = 15.6774(5) Å
β = 108.861(2)°
β = 108.861(2)°
Ratio:
a:b:c = 0.766 : 1 : 1.712
Unit Cell V:
953.41 ų (Calculated from Unit Cell)
Z:
4
Morphology:
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.
Twinning:
On {011}.
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0000300 | Kernite | Cooper W F, Larsen F K, Coppens P, Giese R F (1973) Electron population analysis of accurate diffraction data. V. Structure and one-center charge refinement of the light-atom mineral kernite, Na2B4O6(OH)2.3H2O Extended L-Shell refinement American Mineralogist 58 21-31 |  | 1973 | 0 | 293 | |
| 0000299 | Kernite | Cooper W F, Larsen F K, Coppens P, Giese R F (1973) Electron population analysis of accurate diffraction data. V. Structure and one-center charge refinement of the light-atom mineral kernite, Na2B4O6(OH)2.3H2O high order refinement American Mineralogist 58 21-31 | | 1973 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.40 Å | (100) |
| 6.64 Å | (85) |
| 3.253 Å | (34) |
| 3.132 Å | (29) |
| 2.882 Å | (29) |
| 2.472 Å | (27) |
| 3.705 Å | (23) |
Comments:
Tincalayu deposit, Argentina.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| 25 : Evaporites (prebiotic) |
Geological Setting:
Sedimentary borate deposits.
Type Occurrence of Kernite
General Appearance of Type Material:
Cleavage 2 x 2.5 x 6 inches. Colorless to white and transparent, greatly resembling some specimens of massive selenite.
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, number 95643 (type).
Harvard University, Cambridge, Massachusetts, USA, number 88508.
Harvard University, Cambridge, Massachusetts, USA, number 88508.
Geological Setting of Type Material:
Metamorphosed bedded borate deposit in clay-shales.
Associated Minerals at Type Locality:
Synonyms of Kernite
Other Language Names for Kernite
Common Associates
Associations Based on Photo Data:
| 8 photos of Kernite associated with Gerstleyite | Na2(Sb,As)8S13 · 2H2O |
| 5 photos of Kernite associated with Tincalconite | Na2(B4O7) · 5H2O |
| 4 photos of Kernite associated with Pararealgar | As4S4 |
| 3 photos of Kernite associated with Realgar | As4S4 |
Other Information
Thermal Behaviour:
Alters to metakernite (Na2B4O7·5H2O) upon heating to 100° - 120°C, as a non-reversible change.
Notes:
Slowly soluble in cold water, readily so in hot water.
Alters to tincalconite upon dehydration.
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 petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Kernite
mindat.org URL:
https://www.mindat.org/min-2188.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Kernite
Reference List:
Muessig, Siegfried, Allen, Robert D. (1957) The hydration of kernite. American Mineralogist, 42 (9-10) 699-701
Cooper, W. F., Larsen, F. K., Coppens, P., Giese, and R. F. (1973) Electron population analysis of accurate diffraction data. V. Structure and one-center charge refinement of the light-atom mineral kernite, Na2B4O6(OH)2·3H2O. American Mineralogist, 58 (1-2) 21-31
Jun, Li, Shuping, Xia, Shiyang, Gao (1995) FT-IR and Raman spectroscopic study of hydrated borates. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 51 (4) 519-532 doi:10.1016/0584-8539(94)00183-c
Localities for Kernite
Showing 14 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and 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).
All localities listed without proper references should be considered as questionable.
Antarctica | |
| Fitzpatrick et al. (1990) |
Argentina | |
| Helvaci +4 other references |
China | |
| Kezao Chen (1992) | |
India | |
| Rathore (2015) |
Italy | |
| Chukanov (2014) |
Poland | |
| Cu +2 other references |
Serbia | |
| Putzolu et al. (2025) |
Turkey | |
| Helvaci et al. (2000) +1 other reference |
USA | |
| Rock Currier collection |
| U.S. Borax | |
| Boslough et al. (1980) +1 other reference | |
| Frondel et al. (1956) | |
| Am Min 49:543-555 |
| Schaller (1927) |
Quick NavTopAbout KerniteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesOther InformationKernite in petrologyInternet Links References Localities Locality List
Rio Tinto Borax Mine, Kramer Borate deposit, Boron, Kern County, California, USA