Lab-Created
One of the most popular types of gems is the laboratory-created gemstone. Lab-created gems have the identical chemical composition, crystal structure and appearance of their natural counterparts created by Mother Nature. Because they are made in a laboratory, lab-created gemstones are almost perfect. They are also more affordable than rare, natural gemstones. The most common lab-created gems are emeralds, rubies, sapphires and opals.
Simulated
Simulated gems resemble real gemstones but are made from other natural and synthetic materials and cost much less. Cubic zirconia, which looks like a diamond, is an example of a simulated stone.
Enhanced
Nearly all gemstones available today have been enhanced to bring out their best color or to strengthen them. For example, an accepted industry practice in the polishing process for sapphires involves heating the stones to bring out their color. This process simply extends what nature began, since it is heat and pressure that give gemstones their color in the first place.
