This is a very difficult question which comes up more and more. On this board we have Mike whom we know as probably the most outstanding expert in the world on Okra glass. However, the seller claims to have been told by an Antiques Roadshow expert that the piece is Okra. And Antiques Roadshow experts are like policemen, politicians and bank managers - we trust everything they say, don't we?
If we are prepared to give the seller the benefit of the doubt, perhaps the seller thinks that the Antiques Roadshow is correct and that if Mike is an Okra expert he is trying to get a rare piece on the cheap!!

But seriously most people's attitude is that if the AR expert has said it is Okra then it is.
Perhaps someone could email the seller the link to this thread and maybe they would like to join the board and contribute to the debate. I am not an expert on Okra, but I too know that it is 100% not Okra.
