Na₂B₄O₆(OH)₂.3H₂O

This sample of kernite is displayed in the Smithsonian Museum of Natural History. Kernite is a oxide mineral of boron (a borate) with sodium. It has the composition Na₂B₄O₆(OH)₂.3H₂O. The sample at left is about 8 x 30 cm and is from Kern County, California.

Sodium borates such as kernite with borax (sodium tetraborate decahydrate, Na₂B₄O₇. 10H₂O) and colemanite (calcium hexaborate pentahydrate, Ca₂B₆O₁₁. 5H₂O) form vast deposits of boron in California .