Liking green as much as I do (see previous post) I find the striations (or are they just bands?) in malachite particularly beautiful. I managed to thrift these vintage beads just yesterday. Perhaps not as big as they seem under a macro lens though at about 1cm diameter for the largest. Needless to say I was rather excited at finding them; unloved at the bottom of a bowl of plastic necklaces and tarnished chain.
Malachite is found world wide and I wonder if we don't have a little hiding up here in North Wales. We have old copper mines and I know there are limestone quarries too so, if they meet somewhere in the middle there might just be a little malachite tucked away somewhere.
edit: the 2nd post up from this confirms my suspicions!