The ability to resist fracture is a mechanical property of materials known as fracture toughness. For advanced ceramics it uses a critical stress intensity factor known as KIC where the fracture normally occurs at the crack terminations.The length of the defect and an understanding of the ceramic materials Young’s modulus is needed to measure the KIC.Fracture toughness is a critical metric as it determines how a material performs under given conditions. This is important as even in the highest quality ceramic its nearly impossible to guarantee that the end products are totally free from defects and therefore required to measure performance.