There is a pressing need worldwide to find alternative cementitious materials to produce low-embodied-carbon cement and sustainable concrete. This study compared the potential of quaternary blended cements – limestone calcined clay cements (LC3) – using calcined clays from Australian sources: metakaolin (Mk) from traditionally-accepted kaolinite clay, and a rarely-examined calcined-bentonite (CB). Paste specimens were prepared with optimally calcined clays along with limestone and gypsum to achieve 50% clinker replacement and the properties were compared with an Australian Type General Purpose ordinary Portland cement (OPC) paste. Mechanical strength, phase development and selected durability-indicator properties were investigated on specimens cured for 7 and 28days. Bentonite based LC3 blends achieved about 96% strength, while Mk based LC3 blends achieved about 86% strength of the 28d-old control OPC. Results from X-ray diffraction confirmed the formation of more carboaluminates and ettringite phases in Mk based LC3 blends compared to OPC, but portlandite consumption and ettringite formation indicated greater pozzolanic reaction in bentonite LC3 blends. The resistance to water penetration measured by water absorption and sorptivity in bentonite based LC3 blends was greater or comparable to the control OPC and was greater than Mk based LC3 blends. Overall, these results demonstrate that some bentonites can be used as alternatives to kaolinite for producing LC3 blended cements and suggest that other locally available clay minerals should be investigated for their potential in sustainable cement-production.