Alkali activated products were synthesized by activation of kaolinitic clay from Hiswa area, Jordan with a sodium hydroxide solution. These specimens were subjected to long-term durability tests under different environmental and chemical conditions. The geopolymer specimens undergo very low drying shrinkage. The specimens perform well under ambient, de-ionized water, wet–dry cycles, sea water, and sodium sulfate conditions. The newly developed material from Hiswa clay shows a stable strength under all these conditions. The specimens are however attacked by acid solutions and lose about 9.7% of their mass after 90 days of exposure. The alkali–silica reaction has highly affected the geopolymer specimens as indicated by cracking, expansion and loss of mechanical strength.