Lab-grown diamonds are diamonds that are grown in a laboratory using advanced technological processes that simulate the natural conditions in which diamonds form in the earth's mantle. These diamonds have the same chemical and physical properties as natural diamonds, and they are considered to be real diamonds.
On the other hand, cubic zirconia (CZ) is a man-made gemstone that is made from zirconium dioxide. CZ is a synthetic material that is made to resemble the look of a diamond, but it is not a diamond. Unlike diamonds, CZ is not as hard and durable, and it is also less expensive.
In summary, while both lab-grown diamonds and cubic zirconia are man-made gems, lab-grown diamonds are real diamonds with the same physical and chemical properties as natural diamonds, while cubic zirconia is a synthetic material made to resemble the look of a diamond.