I finally got around to making this sphere from the rock depicted in this previous post: http://spheremaker.com/the-most-beautiful-lake-michigan-stone-ever-found/
I was hesitant to make it because the rough rock was so killer looking and I didn’t and still don’t know what it is. I’ve had some knowledgable folks chime in that it may be basalt, chert, calcite, carnelian, and/or garnet. I imagine its tough to identify from pictures alone. It was harder than I thought it would be, but not as hard as say an agate. The crystals fractured like they do when I would sphere a quartz based rock, which I find many in Michigan. I was hoping it would be crystal in the center but it was not. The sphering process ground off a lot of crystal, but I still think it turned out nice. Interesting thing, it had a lot of little slivers of metal within it. Pyrite maybe? Silver? Who knows. One of my favorites I’ve done though. What do you think?