Modern diamond mining gets in the way of finding big stones. They way it is done now is to crush the kimberlite ore and spread it over a grease covered shaking table. The diamonds stick to the grease and are collected once the waste material falls off. Diamonds are hard, but they are brittle, and the crushing process can destroy bigger stones.

But maybe the crystal was spotted before it went to the crusher...maybe. Security is pretty tight in the mines, reaching into a pile of ore might get you in trouble.

Beyond that, it doesn't look like a rough diamond, it looks polished. The picture on the site is pretty small, but something doesn't look right about the crystal habit.

Just my opinion.

Colorado had a small diamond mine for a year or two. Didn't produce many carots, but I was lucky enough to buy a pair of earrings for Mrs. P. before the mine shut down. It's neat to know exactly where they were mined.