This is the very impressive Golden Snitch necklace/engagement ring box crafted by New Zealand based Freeman Jewelry Design. In the artist's own words while I try to figure out how to prevent my girlfriend from ever seeing this:
The Freeman Design Golden Snitch Inspired Engagement Ring Box, is made to make that special moment an extra special surprise. Made out of Sterling Silver, the Snitch has an extra thick coating of 18ct Yellow Gold, with wings plated in an extra think coating of Rhodium. Made to be a necklace, it comes with a Nimbus 2000 Broomstick Inspired Charm which secretly doubles as the Key to open it. The Hinging and Catch Mechanism is concealed so when shut, keeps the Engagement Ring a complete secret.
The Snitch is made with the aid of 3D computer modeling, which is then 3D printed and cast in Sterling Silver using the Lost Wax Casting Process. With over 30 hours of attentive hand work and scrutiny to finish it to the highest of standards. Hand engraved with 'I Open at the Close' and the lucky receiver's name on the inside. It is fully hand polished, the catch and internal mechanisms are handmade.
No word on the price, but I imagine it's expensive. Still - you only get married a couple times, right? Why not splurge? Plus you could save some money by not actually buying an engagement ring and just telling your girlfriend it's invisible because you put a magic spell on it. Then she'll use her Time-Turner to return to the day you first met and make sure to never bump into you at that coffee shop.
Keep going for a bunch more pics and a brief video.
Thanks to Allyson S, who informed me Golden Snitches do not get stitches, Quidditch players who get hit by Bludgers do.