Abstract: The latest investigation on Kırka borate deposits reveals the existence of a new mineral; kernite(NaBB4O74H2O, which is a sodium-tetraborate ,and it is discovered for the first time in Turkey. After the geologicalposition of samples noted, they have been studied by microscope, chemical analysis, X-ray diffraction, differentialthermic analysis ,and infrared absorption analysis. Colorless, transparent but sometimes white needles / bunch of needles of kernite crystals were found in borax asellipsoidal form where the size, of ellipsoid is in the range of 40 to 60 cms. However, this is the only kernite ellipsoidfound in borax, it is believed that when the underground excavation advances new kernite ellipsoids may be found.Presence of kernite with borax in Kırka borate deposits reveals that the geological conditions differ locally duringthe crystallisation of borates ,and support the idea about the genesis proposed previously (Baysal, 1972 a; 1973 a). Inorder to precipitate kernite instead of borax / converting borax to kernite, it is not necessary to change the chemicalcomposition of the solution, but decrease the activity of water. Activity of water decreases when pressure / temperature / both increases. From this, two possibilities for the occurence of kernite can be suggested. First kernite mayform by dehydration of borax with subsequent local increase of pressure ,and temperature. But, due to structural differences between borax ,and kernite, ,and equilibrium conditions determined by Ataman ,and Baysal (1973) this possibilityless favorable from the second possibility which tiy* authors .believe. In accordance with this, kernite assumed to be formed in the cavities of borax by warmer solutions brought by tiny veinlets.