hello Peter. I assume you are implying a C20 greengrocers stand for display in a shop window etc. - rather than something to do with ornate C18 Irish pineapple holders with their massive Van Dyke type rims.
Could be very wrong, but age wise I'd consider this to be pre 1930/40 - the colour is very slightly greyish, and there are too many small stones to suggest that, quality wise, this is a modern piece of glass - although stones apart it's not a hurriedly cobbled together piece.
I think the suggestion of a support (for articles of some kind) within a retail (shop) environment to be quite probable.
