Been swapping bits in and out of the attic - thought I'd share one of my favourites - by Max Lamb. <click on the small pics for larger ones>
It looks as though Max has first made a vase out of rope, then a clay/ plaster mould (split to get the original shpe out, you can see the join), then blown a vase into the mould, green cased in black, and finally ground back some of the black to the green beneath.
I picked it up at the London Commonwealth Institute glass fair a few years ago. It has a paper sticker on the base, but otherwise unmarked - it's my guess this was a design course bit.