Answer:
Cubic zirconia can be described as the cubic crystalline of zirconium dioxide (ZrO2). Diamond can generally be described as the solid form of Carbon. Cubic zircona is often used as a substitute for diamond. 
Similarities between cubic zirconia and diamond include:
- Both can be used in the making of jewelry or ornaments. 
 - Both are durable.
 - Visually, both cubic zirconia and diamond are very much like each other.
 - Both cubic zirconia and diamond are hard.