Kernite
| Kernite | |
|---|---|
 |
|
| General | |
| Category | Inoborates |
| Formula (repeating unit) |
Na2B4O6(OH)2·3(H2O) |
| Strunz classification | 06.DB.05 |
| Crystal symmetry | Monoclinic prismatic H-M symbol: (2/m) Space group: P 21/c |
| Unit cell | a = 7.0172(2) Å, b = 9.1582(2) Å, c = 15.6774(5) Å, β = 108.861(2)°; Z=4 |
| Identification | |
| Formula mass | 273.22 |
| Color | Colorless, white |
| Crystal habit | Crystalline - occurs as well-formed coarse sized crystals |
| Crystal system | Monoclinic |
| Cleavage | Perfect on [100] and [001], good on [201] |
| Fracture | Splintery |
| Tenacity | Brittle |
| Mohs scale hardness | 2.5-3 |
| Luster | Vitreous - pearly |
| Streak | white |
| Specific gravity | 1.9 - 1.92 |
| Optical properties | Biaxial (-) |
| Refractive index | nα=1.454, nβ=1.472, nγ=1.488 |
| Birefringence | δ =0.0340 |
| 2V angle | 80° |
| Other characteristics | non-radioactive, non-fluorescent, non-magnetic |
| References | [1][2][3] |
Kernite, also known as rasorite is a hydrated sodium borate hydroxide mineral with formula Na2B4O6(OH)2·3(H2O). 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 soluble in cold water and alters to tincalconite when it dehydrates. It undergoes a non-reversible alteration to metakernite (Na2B4O7·5(H2O)) when heated to above 100° C.[2]
Occurrence and history [edit]
The mineral occurs in sedimentary evaporite deposits in arid regions.
Kernite was discovered in 1926 in eastern Kern County, in Southern California, and later named for the county. The occurrence locale was the US Borax Mine at Boron in the western Mojave Desert. The type material is stored at Harvard University, Cambridge, Massachusetts, and the National Museum of Natural History, Washington, D.C.[2]
The Kern County mine was the only known source of the mineral for many years. More recently, kernite was also discovered at and is now mined in Argentina and Turkey.[2]
The largest documented single crystal of kernite measured 2.44x0.9x0.9 m3 and weighed ~3.8 tons.[4]
Uses [edit]
Kernite is used to produce borax which can be used in a variety of soaps.
References [edit]
- ^ Kernite WebMineral
- ^ a b c d Handbook of Mineralogy
- ^ Kernite on Mindat.org
- ^ P. C. Rickwood (1981). "The largest crystals". American Mineralogist 66: 885–907.
Media related to Kernite at Wikimedia Commons
 |
This article about a specific mineral or mineraloid is a stub. You can help Wikipedia by expanding it. |
