Two mainland men were arrested for stealing a diamond worth $210,000 after allegedly swapping it with a fake at the jewellery show yesterday. Police said the two men from Hunan province put up a struggle when they were approached by plain-clothes officers but were eventually subdued. One officer suffered an injury to his right hand and was taken to Ruttonjee Hospital for treatment. Police said an investigation found that the two suspects took a four-carat diamond from a booth and left a similarly sized fake in its place. The real diamond was recovered. Superintendent Chan Kin-hung of Hong Kong Island regional crime unit said a number of fake diamonds were seized from the suspects. The two men, aged 26 and 33, were still being questioned last night and no charges had been laid.