A method of producing hydrothermally stable chabazite (CHA) zeolites is disclosed. The disclosed method is based on the use of reaction mixtures that (1) are essentially void of alkali metal cations and (2) contain the N,N,N-trimethyl-1-adamantyl ammonium (TMAda+) organic as the sole OSDA. The disclosed method results in a higher crystalline CHA zeolite that exhibits hydrothermal stability. There is also disclosed a zeolite material having a CHA-type framework structure made by the disclosed method. A method of selective catalytic reduction of NOx in exhaust gas using the material described herein is also disclosed.