Interesting Rock

I've seen it. Is it mushroom jasper (rhyolite)?

It looks like what I called mushroom rhyolite. Mine were from beaches with volcanic influence in Guaymas Mexico. It can form wonderful patterns but probably varies in the amount of silica and hence in its ability to take a polish and or undercut. Its fun stuff.

Somebody seems to call similar-looking material "Soap Bubble Rhyolite". Don't know if it is an official name or not.

www.instagram.com/rorys_inspiration_lapidary_art/p/CGRWPQ2H2_H/?img_index=1 and some on etsy

Soap bubble “jasper”. This is actually a highly silicified rhyolite. I just collected some from the location at Opal Mountain near Barstow. Where did you get it from Patty?

Ok Patty here you go! Some rough, some slabs we cut, and the first two I will try to do at the club tomorrow. As you can see some of this has orange opal running thru it. I have a couple more chunks that have the orange “lightning” in it.

I will show them as long as I don’t completely embarrass myself by fouling them up lol, I’m still learning and only have a handful of stones under my belt. Thanks for the compliment on the stones, I was jazzed to find these with the bolts in them, they were localized to a small area and I grabbed a few and sent other members over there to pick some up too. The whole Opal Mt area has this soap bubble type stuff in varying qualities and quantities. Where I got the bolts seemed to have the bigger and better pieces. There are literally boulders of it there without the bolts, which is still really neat stuff.

They polished up nicely. I messed up the symmetry on the orange bolt one a bit, but they domed and girdled nicely. This seems harder than your stones though Patty, they grinded more like an agate so maybe it’s not quite the same stuff. The opal tried chipping when I trimmed it up but was fine on the grind. I do better with less symmetrical shapes lol.