I guess each of them is a one off, nature of the beast. Not limited editions as they are not numbered in that fashion. The bases are ground and polished.
The 2007 and the 2009 stones I have seen are signed and dated. The 2007 stones also, as far as I know, have a number engraved (I haven't handled them all so can't be definitive), I am fairly sure the no1, no2 etc. refers to the colour. The blue ones are no1, that amethyst one on ebay was a no2, might as well add a link to it before the photo disappears: http://cgi.ebay.co.uk/ISLE-WIGHT-GLASS-CRIZZLE-STONE-VASE-SIGNED-/330430677708?cmd=ViewItem&pt=UK_Art_Glass&hash=item4cef3402cc
Don't know what the number on the turquoise one
sold at the National was, I think I was offered that one for sale some time ago but I bought this Mdina fish vase
instead. I wish I could have afforded both.
Next time, if there is one, to hell with the overdraft.