Borax (mineral)

For commercial sodium borates, see Borax.
Borax
Borax from the Kramer Borate deposit, Boron, Kern Co, California, USA
General
CategoryNesoborate
Formula
(repeating unit)		Na2B4O5(OH)4·8H2O
IMA symbolBrx[1]
Strunz classification6.DA.10
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/c (no. 15)
Unit cella = 11.8790(2) Å,
b = 10.6440(2) Å,
c = 12.2012(2) Å;
β = 106.617(1)°; Z = 4
Identification
ColorColorless or white
Crystal habitAs prismatic crystals or as massive encrustations
TwinningRare on {100}
CleavagePerfect on {100}, less perfect on {100}, very poor on {010}
FractureConchoidal
Mohs scale hardness2 to 2.5
LusterVitreous to resinous to earthy
StreakWhite
DiaphaneityTranslucent to opaque
Specific gravity1.715
Optical propertiesBiaxial (-)
Refractive indexnα = 1.4466 nβ = 1.4687 nγ = 1.4717
Fusibility1.5
Diagnostic featuresFroths on heating, producing a yellow flame
SolubilitySoluble in water
References[2][3][4][5]

Borax (Na2B4O5(OH)4 · 8 H2O[2]) is a borate mineral found in evaporite deposits of alkaline lacustrine environments and as a surface efflorescence in arid regions. It is the chief mineral mined from the deposits at Boron, California and nearby locations, and is the chief source of commercial borax.[5]

Borax first reached Western civilization as tincal mined from deposits in Tibet.[5] The term borax comes from the Arabic bauraq, meaning white.[3]

Occurrences

The most extensive deposits are in Kirka, Turkey. Borax is also mined in the Andes Mountains of Argentina, Bolivia, and Chile. However, the greatest production is from the deposits in California.[5]

Uses

Natural occurrences of the mineral are an important source of commercial borax, which is used for the manufacture of glass fibers, in cleaning agents, as an antiseptic, and as a flux in metallurgy and solvent for metal oxides.[5]

See also

References

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Borax" (PDF). Handbook of Mineralogy. Retrieved 17 June 2022.
  3. ^ a b Borax, Mindat.org, retrieved 17 June 2022
  4. ^ Sinkankas, John (1964). Mineralogy for amateurs. Princeton, N.J.: Van Nostrand. pp. 382–383. ISBN 0442276249.
  5. ^ a b c d e Klein, Cornelis; Hurlbut, Cornelius S. Jr. (1993). Manual of mineralogy: (after James D. Dana) (21st ed.). New York: Wiley. pp. 421–422. ISBN 047157452X.


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