I currently work at a jewelry store part time and have been with the same company for 10 years. Here is what I have to say about buying a diamond. 1- diamond is still the hardest stone, man made items will scratch and dull over time. If you want something that looks like a diamond and will not scratch or dull try a white sapphire. They don't quite have the sparkle of a diamond but they hold up well. 2- Many jewelry stores will not work on rings with synthetic or man made diamonds. So if you ever need the ring re sized or any work done on it, you will have to search hard for a store to work on it. This is due to liability. 3- You can get good deals on diamonds from places like Blue Nile, however you will also get less customer service after the sale. Shopping at a brick and mortar store will allow you to see the diamond in person and if anything goes wrong they will work to fix it. 4- Why buy a diamond. Many people opt for a colored stone center and it will make it very unique. And as far as cost some Natural Rubies and Emeralds rival the cost of a diamond, but for the most part colored stones are cheaper than diamonds. 5- It shouldn't be about the size and price of a ring. What matters the most is what it symbolizes, but some people tend to forget this while shopping for rings.
