diamonds

an-extinct-volcano-in-arkansas-hosts-the-only-public-diamond-mine-on-earth

An extinct volcano in Arkansas hosts the only public diamond mine on Earth

The park provides two covered pavilions with water troughs and tables for wet sifting, plus open sluice boxes with hand-operated water pumps at both ends of the field. Four shaded structures are available in the search area; however, visitors are also welcome to bring their own canopies or tents, provided they are well-secured.

The diamonds formed under extreme pressure and heat deep in the Earth’s mantle. If you find one, it will most likely look like a metallic or glassy pebble rather than a sparkly cut gem that you might picture in your mind. The volcanic soil also contains amethyst, garnet, jasper, agate, and various types of quartz (and you can keep those, too).

The largest diamond found in the United States came from this field—the 40.23-carat Uncle Sam diamond, discovered in 1924 before the land became a state park. In September 2021, California visitor Noreen Wredberg found a 4.38-carat yellow diamond after searching for two hours, and in 2024, a visitor named Julien Navas found a 7.46-carat diamond at the park.

The park received over 180,000 visitors in 2017, who found 450 certified diamonds of various colors. Of the reported diamond finds, 299 were white, 72 were brown, and 74 were yellow.

Park staff told Mays that visitors find one or two diamonds daily, so “keep your expectations in check,” she writes. Most diamonds discovered are about the size of a paper match head, while a one-carat diamond is roughly the size of a green pea. But even tiny diamonds carry the thrill of discovery. Park staff provide free identification services, examining finds under loupes and confirming whether that glassy pebble is quartz or something more valuable.

A family experience

For those wanting to join the thousands who visit each year, the park makes it affordable. Admission costs $15 for adults, $7 for children ages 6–12. You can camp overnight at the park and return to the field at dawn. During summer months, the park operates a small water park—an acknowledgment that diamond hunting in Arkansas can be brutal, with a heat index exceeding 110° Fahrenheit.

Sometimes rain turns the field into mud, which experienced searchers prefer because it makes diamonds easier to spot—but it can make for a messy adventure. As Mays put it, “Most visitors leave with a handful of interesting rocks, some newfound knowledge, and an urgent need for a long shower.”

If you don’t find any diamonds at the park, don’t despair—you could still potentially buy a $200,000 diamond-making machine on Alibaba.

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you-can-buy-a-diamond-making-machine-for-$200,000-on-alibaba

You can buy a diamond-making machine for $200,000 on Alibaba

Adventures in compressed carbon —

Making diamonds is cheaper than ever, creating a weird problem: too many diamonds.

CLOSE UP: Jeweler looking a diamonds on the work table - stock photo

In an age when you can get just about anything online, it’s probably no surprise that you can buy a diamond-making machine for $200,000 on Chinese eCommerce site Alibaba. If, like me, you haven’t been paying attention to the diamond industry, it turns out that the availability of these machines reflects an ongoing trend toward democratizing diamond production—a process that began decades ago and continues to evolve.

The history of lab-grown diamonds dates back at least half a century. According to Harvard graduate student Javid Lakha, writing in a comprehensive piece on lab-grown diamonds published in Works in Progress last month, the first successful synthesis of diamonds in a laboratory setting occurred in the 1950s. Lakha recounts how Howard Tracy Hall, a chemist at General Electric, created the first lab-grown diamonds using a high-pressure, high-temperature (HPHT) process that mimicked the conditions under which diamonds form in nature.

Since then, diamond-making technology has advanced significantly. Today, there are two primary methods for creating lab-grown diamonds: the HPHT process and chemical vapor deposition (CVD). Both types of machines are now listed on Alibaba, with prices starting at around $200,000, as pointed out in a Hacker News comment by engineer John Nagle (who goes by “Animats” on Hacker News). A CVD machine we found is more pricey, at around $450,000.

  • An image of a “HPHT Cubic Press Synthetic Diamond Making Machine” made by Henan Huanghe Whirlwind Co., Ltd. in China.

  • A photo of part of a “HPHT Cubic Press Synthetic Diamond Making Machine” made by Henan Huanghe Whirlwind Co., Ltd. in China.

  • A photo of a factory full of HPHT Cubic Press Synthetic Diamond Making Machines, made by Henan Huanghe Whirlwind Co., Ltd. in China.

Not a simple operation

While the idea of purchasing a diamond-making machine on Alibaba might be intriguing, it’s important to note that operating one isn’t as simple as plugging it in and watching diamonds form. According to Lakha’s article, these machines require significant expertise and additional resources to operate effectively.

For an HPHT press, you’d need a reliable source of high-quality graphite, metal catalysts like iron or cobalt, and precise temperature and pressure control systems. CVD machines require a steady supply of methane and hydrogen gases, as well as the ability to generate and control microwaves or hot filaments. Both methods need diamond seed crystals to start the growth process.

Moreover, you’d need specialized knowledge to manage the growth parameters, handle potentially hazardous materials and high-pressure equipment safely, and process the resulting raw diamonds into usable gems or industrial components. The machines also use considerable amounts of energy and require regular maintenance. Those factors may make the process subject to some regulations that are far beyond the scope of this piece.

In short, while these machines are more accessible than ever, turning one into a productive diamond-making operation would still require significant investment in equipment, materials, expertise, and safety measures. But hey, a guy can dream, right?

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