It is definitely a legit publicly-traded company that has been around for quite some time now. All of their stones are GIA certified just like any stone you would get from any retail store. As long as you do your research and know exactly (or very close to) what parameters you want in the stone as well as how much you are willing to pay, it is very convenient and easy to shop through Blue Nile, and you get a much better price than shopping retail. From what I remember, they don't have a great selection of rings and settings, so what you can do is purchase a loose stone from BN and then just go to a local jeweler and find a setting that you like. The settings cost a fraction of the price of the stone, so not as much need to shop around for those.
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