Commissioned by Boodles, a custom jewellery company from Britain, the Jewel Royale chess set is the most expensive chess set in the world. Made form gold and platinum, the chess set also uses precious stones like diamonds, rubies, pearls and sapphires. The king piece alone uses 146 diamonds and 73 rubies studded in 165.2 grams of 18 carat gold. Priced at about 9.8 million USD, this is certainly the most expensive chess set.