Garnet. Credit: Mineral Information Institute.
Kernite is a mineral form of hydrated sodium tetraborate (Na2B4O7.4H2O), first found in 1926 associated with borax in Kern County, California. Deposits of it were later discovered and mined in Argentina, Spain, and Turkey. Kernite forms colorless monoclinic crystals, and occurs as veins in clay shale beds. It is a major source of boron.