This is a pretty half-circular Irish crochet motif.
This link will take you to this lovely motif. The instructions are in Russian, but there are some pretty good photos to follow.
My sample looks lime this so far:
I have had to do some ripping and re-crocheting. But all in all, this is a pretty and dainty little motif.
You can also just make it into a round motif. Just be sure to add more stitching into your original ring.
Good luck and have fun with this! :)