I have had this heavy, five and a half inch vase for some years and although I had originally thought it might be neodymium I dismissed the thought as had quite wrongly believed that the colour changes in neodymium would be shown by exposure to UV light. A few days ago I put a low energy bulb in my study and lo and behold my daylight purple vase became blue. Just shows what a single incorrect assumption can do. Any ideas where it came from would be appreciated. As I'm in the U.K. I'm thinking perhaps Caithness?