This David Yurman Petite Albion Ring/Prasiolite costs $590 at Saks Fifth Avenue. If you're not familiar with David Yurman, it's a high-end American designer jewelry company headquartered in New York City that's quite popular with the moneyed crowd. To see Lauren Conrad wearing this ring, click here.
Here's another piece by David Yurman to give you a sense of what his signature designs look like. It's a Blue Topaz Ring which costs $850, also at Saks Fifth Avenue.
Over the Thanksgiving holiday, I saw a dear sweet friend of mine who happened to be wearing the ring shown here. I totally thought it was a David Yurman but she just laughed and said it was from Kohls. You can purchase this ring from Kohls.com for just $6.49 on sale.
Here's how the ring looks in real life. As you can see, it's not identical to the David Yurman rings above but it definitely has a similar look and feel. So pretty and such a steal!