The Search for Diamonds in Minnesota

Harvey Thorleifson: Diamond is the high-pressure crystal form of carbon; therefore, diamonds can only be produced deep in the earth. So to produce a natural diamond we need the help of kimberlite intrusions, which are high-pressure leaks derived from deep within the earth. And those high-pressure leaks can only tap diamond-bearing rocks in the old, thick cores of our continents. This is why there is diamond production in South Africa, Russia, and now Canada. Although the recent ice age made things difficult in North America, and we needed high-tech methods to deal with our ice-age soils. That's the reason diamonds haven't been traditionally mined in North America. In Minnesota, the number-one consideration is the old, thick rock. Subsequent to that is the fact that we had faint but clear indication of the right minerals in our soil.

CP: Realistically, could diamonds be a major part of Minnesota's economy in the future?

HT: It's possible. However, much work would be required, combined with good fortune, and then, as with all mining development, environmental impacts would have to be carefully considered. But it is possible.

CP: What will we learn about our state and geography if diamonds are discovered?

HT: It would attract attention to Minnesota's geology. Kimberlites are a tremendous resource, and we as scientists become very excited about the scientific discoveries that come from those deep materials. But surprisingly, in addition to those deep materials, kimberlites preserve the materials at the earth's surface at the time, so they can have fossils; they are an amazing scientific extravagance.