(IDEX Online) - The retail price of polished diamonds in China has remained stable over the last six months, despite a collapse in the rough market.That's according to an informal survey of salespeople at major jewelry stores in Shanghai, by Yicai Global, an English language state-owned news service.Staff at Chow Tai Fook Jewellery, Leysen Jewellery, Kimberlite Diamond and other retailers said rough prices had so far had little impact on polished prices."Diamond prices in our store have not fallen, but have been increasing over the past two years," said a salesperson at Chow Tai Seng.Another said there were many other factors in the cost of a finished jewelry item - the cost of gold and other gemstones, design, labor, and brand premium - so that a drop in rough prices had yet to impact the price paid by consumers.