It's a ring created using a icosahedron as a jewel on top.
I've tryied couple of different ways to place the ring on the makerBot's bed. The best result came with this model.
The ring at this model is a size 8. If you would like to adjust it you can add or subtract material from the ring part.
I made white and black versions of it. I like the black the best.
I recommend using an outside raft support to print it clean. It comes out ok without a support too but not as smooth as one might like.