Underwater diamond mining already exists. Mighty Ships did an episode about it: <a href="http:&#x2F;&#x2F;www.smithsonianchannel.com&#x2F;shows&#x2F;mighty-ships&#x2F;peace-in-africa&#x2F;809&#x2F;3399768" rel="nofollow">http:&#x2F;&#x2F;www.smithsonianchannel.com&#x2F;shows&#x2F;mighty-ships&#x2F;peace-i...</a>