Karelian Diamond Resources tripled at one stage after Rio Tinto agreed to hand over confidential information and physical geological samples relating to exploration in Finland.The data will help AIM-listed Karelian assess its potential and existing exploration programmes in Finland.In return, it has granted Rio the option to earn a 51% interest in any major diamond or other mineral project identified by Karelian in Finland. The Australian mining giant will have to pay the direct cash costs incurred in developing the project."I am delighted with the Agreement with Rio Tinto," said Karelian chairman Richard Conroy. "The confidential information and physical samples now being made available to Karelian will be a significant addition to Karelian's existing knowledge base and mineral exploration programme, which itself has already led to the delineation by Karelian of the largest diamondiferous kimberlite pipe yet discovered in Finland.""The company's objective remains to make a major diamond discovery in Finland comparable to the world class discoveries already made on the Russian side of the structure."