i was walking metal detecting the desert yesterday and started seeing these little rocks.... they have a outer milky white outside and a darker inside, when broken they are very smooth, i found them in new mexico, any ideas?
They could be obsidian. My grandparents had alot of what they called "apache tears". They're obsidian that was expelled forcefully during an eruption and cooled before they hit the ground. The white stuff on the outside is some of the other minerals that were present, and cooled at a different rate. Just a guess...
as far as I know Apache tears are black.I think Wetgreenie is reffering to blue lace agate.but I think it's to dark blue for that.I'd also guees on Iolite