Kernite (also Rasorit ) is a rarely occurring mineral from the mineral class of " borates " (formerly " carbonates, nitrates and borates ", see Classification ). It crystallizes in the monoclinic crystal system with the composition Na2 [ B4O6 (OH ) 2] · 3 H2O, that is chemically a sodium tetraborate.
Kernite usually develops colorless to white, isometric shaped crystals whose surfaces have vitreous luster. Often, however, also silky, fibrous, granular or massive aggregates of up to 3.5 m in size have been found.
Kernite is water soluble, so it must be kept protected as a mineral specimen from moisture.
Etymology and history
Was first found in the kernite Kramer borate deposit " Rich Station" at Boron in Kern County in California and described in 1927 by Waldemar named Theodore Schaller, of the mineral after its type locality ( Kern County ).
Type material of the mineral is preserved in the Harvard University in Cambridge, Massachusetts ( Register-Nr. 88508 ) and the National Museum of Natural History in Washington, DC, USA ( Register-Nr. 95643 ).
In the now outdated but still in use 8th edition of the mineral classification by Strunz the kernite belonged to common mineral class of " carbonates, nitrates and borates " and then to the Department of " chain borates ", where he formed an independent group with no other relatives.
The 9th edition valid since 2001 and of the International Mineralogical Association (IMA ) used the Strunz'schen Mineral classification assigns the kernite in the now independent class of " borates " and there in the department of " Tetraborate " one. This division, however, is further subdivided according to the crystal structure, so that the mineral according to its construction in the subsection " chain and belt ( Ino ) Tetraborate " is to find where it forms the unnamed group 6.DB.05 the only member.
The mostly commonly used in English-speaking classification of minerals according to Dana assigns the kernite contrast, as the outdated 8th edition of the Strunz'schen systematics in the common class of " carbonates, nitrates and borates ," there but in the department of " water -containing borates with hydroxyl or halogen " one. Here he is the only member of the unnamed group 26.04.05 within the sub-division of finding " water -containing borates with hydroxyl or halogen".
Education and Locations
Kernite formed by sedimentation in boron-containing deposits. Accompanying minerals include borax, Inyoite, ulexite and colemanite.
Worldwide, kernite so far (as of 2011) are detected in 10 localities. One of the most important deposits of the mineral is in the eastern part of the core counties Mojave Desert in California.
In addition kernite was still found at Otis in also located in California San Bernardino County, in the province of Salta in Argentina, Catalonia in Spain and in the borate deposit at kirka in the Turkish province of Eskişehir.
Kernite crystallizes in the monoclinic space group P21 / a ( Raumgruppen-Nr. 14) with the lattice parameters a = 15.68 Å; b = 9.16 Å; c = 7.02 Å and 108.9 ° and β = 4 formula units per unit cell.
Kernite despite its rarity, with a content of up to 14.9 % of boron is an important ore for the extraction of this element for the chemical industry.