Zirconia, or zirconium dioxide (ZrO2), is a white crystalline oxide of zirconium. It is known for its high strength, durability, and resistance to heat and wear, making it useful in various applications, including dental ceramics, cutting tools, and refractory materials. In addition to its industrial uses, zirconia is also popular in jewelry as a diamond substitute due to its brilliance and clarity. Unlike natural diamonds, zirconia is synthetic and can be produced in various colors, making it a versatile choice for decorative purposes.