That's an actual sapphire with lab grown diamonds on a Crocs charm made to look like an engagement ring - so you can propose and put the charm on their Crocs instead of on their finger - for the low, low price of $2,000.
The company behind this, Jessica Flynn, does make really gorgeous jewelry. I suspect the Crocs charm engagement ring is brilliant piece of marketing to get people talking, and it worked! Because not only am I talking about, I'm also browsing their website. Ha. Well done!