The raw materials of some volcanic islands started in diamond-bearing regions under continents. The new study asserts that material from diamond-forming regions journeys nearly to earth's core and back up to form such islands, a process that could take 2.5 billion years or longer.

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The raw materials of some volcanic islands started in diamond-bearing regions under continents. The new study asserts that material from diamond-forming regions journeys nearly to earth's core and back up to form such islands, a process that could take 2.5 billion years or longer.