Very nice larger size cab of Howardite., also known as Rattlesnake stone. Great pattern, this is the pattern that's highly sought after in this material.
Howardite was dug many years ago in northern Nevada and only found in old collections these days. It's a rare form of opalized/silicated volcanic tuff. The dark spots are actually translucent agate.
Cut into a freeform design that should be a pleasure to design around. Flat back and low domed top. Both sides have a glassy polish. A couple or so very minuscule pits to be expected in this material. So small you'll need to look very close to find them. This cab is about as good as it gets for this rare material. This will make a fine piece of jewelry or nice addition to your collection.