based on the principles of supply and demand as well as new economies entering the market. Rio Tinto has announced that they intend to close the Argyle Mine in Western Australia in 2016–2018 which will impact the dwindling supply. In its Global Diamond Report 2014, Bain & Co reports that demand for investment diamonds accounts for less than 5% of the total value of polished diamonds. It also reports that diamond prices have benefited from 1.6x lower volatility than gold. Characteristics of investment-grade polished diamonds are highest color (D, E, F) and clarity (IF, VVS1, VVS2), weights ranging from 1 to 10 carats, triple-EX grading (Excellent Cut, Excellent Polish, Excellent Symmetry), and no fluorescence. Polki (unfaceted) diamonds Old diamond jewellery in India, specially from the Mughal period, uses unfaceted diamonds. Mughal style jewellery has become popular in India recently featuring uncut diamonds termed "Polki" (which originally referred to a style of cleaving diamonds). The diamonds used in modern polki jewellery are low grade and do not have much investment value, even though polki jewellery can be expensive. The diamonds are backed by silver foil to allow light to reflect. The Kundan jewellery in India uses the same style, but it uses glass instead of diamonds. Funds In June 2012, Finanz Konzept AG launched the worldwide first actively managed physical diamond fund, which invests in natural physical polished diamonds and coloured diamonds. In November 2012, PureFunds launched an Exchange Traded Fund listed on the New York Stock Exchange that invests in companies engaged in the diamond industry, rather than invest in physical diamonds. The fund ceased trading on January 23, 2014. Mining companies Mining companies produce and sell rough diamonds. Given the very high expense of operating a diamond mine, many diamond mining companies are public and/or owned by governments. The largest diamond company in the world is Alrosa, which surpassed De Beers in carat production in 2008. De Beers is privately owned by Anglo American (85%) and the Botswana government (15%), so its shares are not traded on the stock market. The Oppenheimer family had previously owned a 40% stake in De Beers, but this was sold to Anglo American in 2011. Rio Tinto and BHP are the next largest producers, but diamond mining is a small part of their commodity portfolio. Recycled diamonds Diamond, because of its hardness, is one of the few gemstones that has a recycled market.