Zirconia, also known as zirconium oxide is best known among ceramic raw materials as being both hard and fracture-tough at room temperature. Additionally, its fine grain size enables excellent surface finishes and the ability to hold a sharp edge. It is commonly blended with a stabilizer such as Magnesia (MgO), Calcia (CaO), or Yttria (Y₂O₃) in order to facilitate transformation toughening.