Best Places To Mine For Diamonds in The United States

Where To Mine For Diamonds in The United States

While the United States isn’t teeming with them, there are certainly diamonds present in the continental US. It’s just a matter of knowing where to look. It might also help if you learn a little bit about the formation of diamonds since some are scattered across wide areas instead of being concentrated in a tight spot.

So, let’s take a short look at how diamonds form and then we’ll discuss the best places to mine for diamonds in the United States.

Related: One-of-a-Kind Discovery: Unusual Diamond Found with Another Diamond Inside

The Unique Requirements for Diamond Formation

Diamonds are a bit different from other gemstones. While stones like corundum (ruby and sapphire) are comprised of a few elements, diamonds are actually pure carbon. Most forms of carbon aren’t quite the highlight in our daily lives. They include things like candle soot, charcoal, and graphite.

A diamond is essentially graphite that has been placed under enormous pressure and subjected to high temperatures. These cause the carbon atoms, arranged in layers of a material called graphene in normal graphite, to alter into a cubic crystalline structure. These are most commonly seen as octahedral (8-sided) crystals when found.

Diamond has a strong association with the rock family called kimberlite. Kimberlite isn’t found in the crust of the Earth but instead comes from the upper mantle which lies underneath as magma swells upwards. This forms into structures known as kimberlite pipes due to the way the high-pressure magma escapes violently.

Kimberlite is a rare stone, and it’s a bit unstable, but it’s one of the only indications that diamonds can be found in the nearby area. The only other stone which contains diamonds is lamproite, a similar stone that sources its minerals from the upper mantle.

These conditions are rare, and only a small fraction of them contain enough diamonds to be worth mining.

There are no commercial diamond mines in the United States at present,  but there are a few places where you can find one of your own.

1. Crater of Diamonds

Your best bet at finding a diamond in the US is always going to be Crater of Diamonds in Arkansas. This site is the only 100% open to the public diamond mine in the world, and regularly produces shining stones. While not commercially viable, there have been some rather impressive diamonds unearthed at the State Park, including the 40.23-carat Uncle Sam, which is currently a 12.42-carat emerald cut gemstone after being cut twice.

In addition to the diamonds found in this area, there is also a wide range of other minerals. These include such favorites as amethyst and garnet. For most rockhounds in the area, of course, the real catch is the diamonds that exist in the 37-acre volcanic crater.

At one point in the past the land was considered commercially viable for diamond production. Over the years the property switched hands multiple times as people sought to make a fortune with the diamonds in the area but it was finally passed to the State of Arkansas in 1972, a blessing considering it remains open to the public.

This is your best bet for finding diamonds in the United States, by far, and dozens of diamonds are unearthed here every year. With the other minerals present as well, it’s an attractive place to head for any rockhound looking to gather some stones and the area explicitly allows for the collection and removal of stones from the park’s general area. 

Related: The Uncle Sam Diamond: Unveiled After 40 Years (The Story Behind This Record Setting Diamond)

2. Kelsey Lake Mine

The Kelsey Lake Mine was another diamond mine that was able to be commercially exploited for a bit. Currently, the defunct Colorado mine has been reclaimed but that hasn’t stopped people from searching the area for diamonds. It’s located in the Kimberlite Stateline District, right on the border with Wyoming. This area produced some pretty impressive gemstones but was declared unprofitable and shut down. The mine has now been reclaimed, making it hard to tell from the surrounding area.

The mining operations in this area identified nine kimberlite pipes, three of which were found to be diamond-bearing. Only two of these were opened up before the mine closed. Much of the remains of these pipes is on private land, unfortunately, but there are a few areas in the region you may be able to explore. It’s still far from a sure shot.

Instead of looking over the pipes directly, many diamonds have been found in alluvial deposits in the nearby waterways and others have been dredged up by those sluicing for gold in the same area. It’s more of an interesting side catch than a diamond hotspot, but if you’re after gold, or even just an adventure, then it may be well worth your time.

3. California Gold Country

Here’s where things get a bit odd. I honestly don’t recommend heading out to the Sierras hoping to find diamonds, especially since gold is a much more attractive prospect in that area. Diamonds have turned up on occasion since the time of the Gold Rush, but no one is quite sure of their actual source.

Instead, they’re found almost exclusively in alluvial deposits in Northern California. The most prolific source of diamonds in California has been Cherokee Flat in Butte County. The diamonds found in California have occasionally been gem grade but the largest found until the late 1980s was about 6 carats. These exceedingly rare diamonds have fascinated many. Over time things can move rather far, and a diamond could mean there’s a kimberlite pipe somewhere nearby, such as within a thousand miles.

There is some evidence of a common source in some places in California. In the late 1980s four large, industrial-grade diamonds were found in Trinity County. All four of these showed a rather curious trait in common: they held two generations of diamond growth inside of them. The initial growth was covered again by a layer of diamond at a later date from the initial formation.

There’s plenty to love about California’s Gold Country, from beautiful mountains to varied minerals to prospecting for gold. And, if you get really lucky, you might just find yourself a diamond, which makes the idea of traveling here even more attractive!

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