So...I've sold a ton of these fake agate beads.
I was told they were made in the middle East...poss Iran.
They go way back and can be over 1,000yrs old.
They come in brown,green,blue and pink. Maybe even more colors then that.
They are pricy on the bead market.
The white speckled ones look like Peking glass to me.
I'm sure you'll get some more valuable information as time goes by.
Hope this helps a little.