I'd love to see your heart! I wonder how it would be to 'pot' it in resin? It would never deteriorate that way. There are small boxes of resin for sale in the hobby shops. I have some, but haven't used it yet. I understand bubbles are the hardest thing when using this stuff.
I recently noticed a piece of flagstone that was about 3ft by 3ft and it had a circle carved out of the center of it. It was being used as a garden sculpture. Now I'm tempted to get a flagstone and cut it out that way. I'd fill the center with a stained glass work. I'd have to situate it in a very protected place because we get high winds. Does that sound like it would work?