This stone combination is one I stumbled upon when I was working on the “the road ahead” project in January - shungite and black opal. Shungite is new to me; it’s an opaque black stone with an extraordinarily high carbon content (up to 99%!) and it’s a lot like hematite - grounding and quieting. And then, of course, opal, with all its fire - it’s a really nice combination.