What is a Simulated Diamond?

Lab created diamonds are much cheaper than natural diamonds. they are still diamonds, and are actually much higher quality than "real" diamonds. Also, there are some messy political and social issues surrounding a lot of natural diamonds, and lab created, or "synthetic" diamonds don't have those issues. 

If it just bothers you for some reason to have a diamond that was created rather than found, then spend the extra for a natural diamond. Sometimes they are referred to as certified diamonds, which just means that they've been inspected and their flaws documented.

• Simulated diamonds are also known as diamond simulants and include things like cubic zirconia (CZ), moissanite, and YAG. They can also include some natural clear gemstones like white sapphire, white zircon or even clear quartz.
• Synthetic diamonds are also known as laboratory-grown diamonds, laboratory-created diamonds, cultured diamonds, or cultivated diamonds. They are real diamonds but not grown by Mother Nature.

Diamonds, both real and synthetic, are created under extreme pressure and in high temperature. While real diamonds are formed naturally in the mantle which is 150 km below the earth's surface, synthetic diamonds are created by the HPHT method or the High Pressure High Temperature method that imitates the method by which diamonds are created. These diamonds are formed when carbon is crystallized under the pressure of the crust of the earth in the high temperature of the core. It takes millions of years for the formation of diamonds. Simulated diamonds, on the other hand, may either be found naturally or be man-made and do not have the same molecular structure as actual or synthetic diamonds.There are several different lab processes that are used to make simulants.

It is obvious that real diamonds are much more expensive as compared to simulants. You could probably buy a simulated diamond for  a fraction of the cost of an actual diamond.