Police guard for gem exhibition. City police and Scotland Yard were today keeping a wary eye on gems valued at ?00,000 on show at the Gemmological Associations two-day exhibition, opened today (Wednesday) at Goldsmiths Hall, London Pride of place in the display is taken by the 'Queen of Australia' a magnificent 100 carat Opal , owned by the Duke of Devonshire. Other items of interest are Brazilianite, a new mineral of gem like quality, on view in Europe for the first time, and an 'ersatz' former Sapphire, discovered by British scientists and use for service weapons and equipment during the war. Photo shows, Miss Bridget Jones , admiring a replica set of world famous diamonds, mostly included in the Crown Jewels, on view at the Gemmological Exhibition in London today (Wednesday). 8 January 1947