Scalloped Halo Engagement Ring 3d ModelScalloped Halo Engagement Ring Downloadable 3d Model (Stl File) The ring can be set with 1 6mm round center stone and 12 2mm round gemstones.. The ring is your traditional halo design with a scalloped halo plate around each stone. This helps accentuate the stones more as almost no metal can be seen around the stones. The open gallery is also a simple but elegant design helping bring the ring together as one piece, but not over powering the main focal