Kernite

Kernite
General
Category	Inoborates
Chemical formula	Na2B4O6(OH)2·3(H2O)
Strunz classification	06.DB.05
Identification
Molar mass	290.28
Color	Colorless, white
Crystal habit	Crystalline - Coarse - Occurs as well-formed coarse sized crystals
Crystal system	Monoclinic, (2/m) Space Group P 21/c
Cleavage	[100] Perfect, [001] Perfect, [201] Good
Fracture	Brittle - Generally displayed by glasses and most non-metallic minerals
Mohs scale hardness	2.5-3
Luster	Vitreous - Pearly
Streak	white
Specific gravity	1.9 - 1.92, Average = 1.91
Optical properties	Biaxial (-), 2V=80
Refractive index	nα=1.454, nβ=1.472, nγ=1.488
Birefringence	δ =0.0340
Other characteristics	non-radioactive, non-fluorescent, non-magnetic
References

Kernite, also known as rasorite is a hydrated sodium borate hydroxide mineral with formula Na₂B₄O₆(OH)₂·3H₂O. It is a colorless to white mineral crystallizing in the monoclinic crystal system typically occurring as prismatic to acicular crystals or granular masses. It is relatively soft with Mohs hardness of 2.5 to 3 and light with a specific gravity of 1.91. It exhibits perfect cleavage and a brittle fracture. Kernite is used to produce borax which can be used in a variety of soaps.

The mineral was discovered in 1926 in Kern County, California and later named for the county. Kern County was the only known source of kernite for many years, but kernite is now also mined in Argentina, Spain, and Turkey. It occurs in sedimentary evaporite deposits in arid regions. The largest documented single crystal of kernite measured 2.44x0.9x0.9 m³ and weighed ~3.8 tons.

References

• Mindat with location data