It may be called a 'gift from heaven', but a government delegation from Madagascar said yesterday a large, rough gemstone on display in Kowloon was taken from the island nation illegally. The 536kg stone - which is encrusted with emeralds - has been on display at the BaoQu Tang Modern Art Gallery in the InterContinental Hong Kong in Tsim Sha Tsui since June 20. The gallery claims the 'miracle of nature' is owned by French-registered company Orgaco, but the government of Madagascar alleges the stone was spirited from the island nation illegally and must be returned. Luc Herve Rakotoarimanana, a member of the government delegation, said excavators only had permission to mine for green beryl last year, and should have declared any emerald finds to the government. 'According to Malagasy law, all mineral substances underground belong to the Malagasy state,' Mr Rakotoarimanana said, reading from a Madagascan government statement. 'And to access this property, it will be necessary to get an exploitation license related to the mineral substances legally authorised to be extracted.' According to the statement, the stone was allegedly sold to Chan Sicpo, a Madagascan resident, who took it to Reunion Island. Chan, a painter, has artwork on display at the gallery which was inspired by the rock, according to the gallery. The Hong Kong exhibition is overseen by Reunion Island curators. Mr Rakotoarimanana - whose delegation listed his position as the head of Interpol Madagascar - said his group was working with Hong Kong's police and judiciary to retrieve the emerald. 'Everybody's trying to do their best to solve the problem,' he said. 'We will stay until we have a positive response.' Hong Kong police declined to comment. A legal expert said the outcome of a criminal or civil case depended on the evidence. 'For a criminal case to be proved in Hong Kong, one has to prove that a person had committed a theft offence in Madagascar, and then the one who handled this property [in Hong Kong] had to know it was stolen property,' said barrister Jackson Poon. In a civil case, a 'chain of ownership' must be proven, he added. Last month, the gallery - which has never placed a value on the gemstone - was touting its beauty, noting how it was a 'miracle of nature' found in an open-cast mine in Morafeno in July last year. Yesterday, the gallery found itself defending Orgaco, rattling off reasons in an e-mail why the company should be in the clear. First, a French justice on Reunion Island, east of Madagascar, had found the stone was legally exported, the gallery said. Secondly, Madagascar's head of customs had said in a television interview that all the documents were in order, it added. Moreover, 'emerald is a silicate of beryllium, a member of the beryl family', the gallery said. 'Beryl is the substance; emerald is the colour of the substance.'