The Iris ring has a working mechanical shutter mechanism which reveals a hidden stone. It could optionally hide a laser engraved letter. The tiny shutter vanes with special gear mechanisms were specifically engineered to fit on a ring and are laser cut from aerospace grade titanium.
The ring is 9mm wide and the stone is 8mm diameter. It can be a lab created birthstone like this amethyst or can be a clear CZ. Just specify in the Comments section.