Kurnakovite

specimen number:
2133364

location:
Kramer deposit, Boron, Kern Co., California, USA

description:
A crude but incredibly large colorless to grade translucent crystal of kurnakovite. Complete all around and in good condition.

The Kramer borate deposit, located at Boron in the western Mojave Desert of Kern County, California, is one of the world's largest and most significant open-pit borax mining operations. Geologically, the deposit is hosted within the Miocene-aged Ricardo Group (formerly the Kramer Beds), where structurally controlled, lacustrine sedimentary basins filled with sodium borate salts. The orebody formed in an ancient, closed-basin volcanic lake fed by thermal springs, resulting in a thick, stratified lens of primary borates, chiefly borax and kernite, interbedded with tuffaceous siltstones and clays. Commercial underground mining began at the site shortly after its discovery in 1925 by William M. Suckow and the Pacific Coast Borax Company. Operations transitioned entirely to a massive open-pit quarrying system in 1957 to allow for bulk-tonnage extraction, and the mine has maintained continuous, high-volume production for over a century, currently operating under United Borax (a subsidiary of Rio Tinto) to supply global industrial and agricultural markets.

Kurnakovite is a rare hydrated magnesium borate mineral that occurs as a secondary phase within the localized, magnesium-rich portions of the Kramer deposit. The mineral forms under specific low-temperature hydrochemical conditions within the borate-bearing sediments where circulating fluids experience an enrichment in magnesium relative to sodium. It crystallizes in the triclinic system, typically occurring at the Boron locality as sharp, colorless to chalky white prismatic crystals or dense nodular cleavages embedded in clay matrices. Within the Kramer orebody, kurnakovite is an important diagnostic mineral for identifying geochemical facies variations, and the open pit remains one of the premier global sources for well-formed crystalline specimens of this unusual species.

Questions about this specimen?
Send an email or call us: 314-341-1811.