I found three out of four Bell jars! Good news. The stone hearts will be resting on a silver foot. A friend and collegue artist is working on that. Her site: http://www.ingridadriaenssensedelsmid.be/
Meanwhile I mamaged to visit 'La carriére de Luget', en France. The owner of the holiday house happened to know the owner of the carriére. Very interesting, since the take the stones out of a gigantic 'pit'. Never saw that before!