As another poster indicated that is an electro-plated set of cubic zirconia. It's costume jewelry, so no to answer your question, it's not the real stuff.

Personally, I think it's perfectly fine to get a CZ engagement ring if you like it and it fits within your budget. Those home shopping channels sell a variety of CZs under different trade names and many of them are set in gold or silver. They are a bit more expensive than the set that you purchased, but they will hold up to regular wear much better than an electro-plated set.

We buy these sets all the time for my mother because she LOVES giant rings (3ct and larger), but doesn't want the stress of wearing a real diamond of that size and price. She has her giant rocks this way, but no stress associated with wearing them. It's a perfect solution for her love of bling!

Best wishes!!!!!!!!!!!