Diamonds Unearthed

In part two of this series, Smithsonian diamond expert Jeffrey Post, curator of the National Gem and Mineral Collection, discusses conflict diamonds, colored diamonds and synthetic gems grown in the lab

Jeweler Harry Winston donated the famous Hope Diamond—the largest-known deep blue diamond in the world—to the Smithsonian Institution in 1958. It arrived in a plain brown package by registered mail, insured for one million dollars. Surrounded by 16 white pear-shaped and cushion-cut diamonds and hanging from a chain with 45 diamonds, the rare gem attracts 6 million visitors a year to the Natural History Museum. (Chip Clark)

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Another way of producing diamonds in the lab is out of a gas. Basically it’s a reduction process. You start with methane gas. It’s mixed with hydrogen gas, which reduces the methane. Under the right conditions, a partial vacuum, you can form diamonds. There are a number of different detailed processes, industrial secrets, but that’s the basic technique.

Under the right conditions, with the right mixtures of gases, you can literally form diamonds in thick sheets. These sheets are the kinds of things that could be used potentially for heat sinks or other industrial applications where you need to cut shapes or cut large windows or plates out of diamond. So there’s a lot of speculation that if these producers of sheets of chemical vapor deposition (CVD) diamond can produce enough high-quality diamonds that are thick enough and uniform enough, there will be a huge industrial advancement in the use of diamonds.

When were synthetic diamonds first produced?

In the 1950s, GE developed the reproducible, industrial scale process for synthesizing diamonds. Since then, the industry has really grown and improved.

Are colored diamonds being produced synthetically?

It’s possible to synthesize a colored diamond. Colored diamonds will probably be the most important way in which synthetic diamonds affect the market because of the high prices of natural colored diamonds, They’re really focusing on the yellows right now, but they can do blues and pinks as well. You can synthesize yellow diamonds and sell a one-carat, yellow diamond for 10 or 20 percent of the price of what a natural colored diamond would be. For people who are more interested in having a large colored diamond than they are in having a natural, large yellow colored diamond, they can buy it for a small fraction of the price. This is a place, a niche, which the synthetic diamond producers are really trying to exploit. They can produce the colored diamonds at a price that is so much less than the natural-colored stones, and they can produce a steady supply of them, so the market can build around them. They’re banking on the fact that there will be enough people out there that will be happy to buy a synthetic colored diamond and pay a lot less money for it.

In part one of this three-part series, diamond expert Jeffrey Post, curator of the National Gem and Mineral collection, explains how the rare crystals form. In the final installment, discover the fascinating stories behind the Smithsonian's collection.


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