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Index | History | Where Diamonds Come From | Man Made Diamonds
What to Look For | Fakes

Manufactured Diamonds

Because they are the hardest substance found in nature, diamonds can be useful in many applications. However, the rarity of diamonds makes it cost prohibitive to use natural diamonds. Nevertheless, the market system has prompted companies to find ways to create artificial diamonds for use in industrial applications.

Artificial diamonds are made in a factory that mimics the natural production of diamonds. Just as in nature, the process begins with carbon. The artificial production of diamonds began with a man named Henri Moissan in 1893 who created the first primitive man-made diamonds. In 1892, Moissan theorized that by crystallizing carbon under pressure from molten iron he could make diamonds. To this end he designed and developed the electric-arc furnace, which could attain temperatures up to 3,500° C. With this he was able to make tiny artificial stones.1

Tremendous as this discovery was, large scale production of artificial diamonds was still in the future. Many scientists and engineers replicated these ideas, making adjustments to produce better quality results. It was not until 1954 that the first commercially available man-made diamonds were produced. This development amazed the general public. In spite of the greater availability of diamonds, however, the prices did not rapidly decline as might have been expected, because the man-made diamonds were manufactured primarily for industrial applications and because the size of man-made diamonds have for many years been very small.

High Pressure High Temperature (HPHT)

Even so, a great demand for artificial diamonds spawned a plethora of companies to mass produce them. Today there are two primary ways companies produce artificial diamonds. The most obvious is the High Pressure High Temperature method, or HPHT. This is the least expensive method. As might be expected, HPHT replicates the natural process of the earth by putting very high temperatures and pressures onto carbon. Since this process is so highly temperamental, companies have studied and fine-tuned the process over a period of many years. A belt press is normally used; anvils bring the required pressure and a heating current. Steel bands maintain the internal pressure that is needed.

Chemical Vapor Deposition

The second process used to make artificial diamonds is called Chemical Vapor Deposition or CVD. This is a revolutionary form of diamond making that has been turning a lot of heads. It involves sending carbon and hydrogen gases into a chamber. The chamber contains heating elements such as filaments and microwaves. The gas is broken down. Then the usual heat and pressure are applied. CVD has been generating excitement in the diamond making field because it allows manufacturers more control over the process. Also, larger diamonds can be made using this method.

Although it sounds quite simple, applying heat and pressure, Making diamonds is a highly complicated process that requires the right chemistry to be applied. A lot of research goes on behind the scenes to perfect the artificial diamond making process. CVD is also a fairly costly process, which causes companies to return to the less appealing HPHT process.

Nevertheless, new processes like CVD, and using seed diamonds grafted with molten graphite put under pressure, have begun to produce gem sized artificial diamonds. This may create a revolution in the diamond industry. Today the argument is rising over the relative value of artificial versus mined diamonds. In fact, there is no real difference on the chemical and structural levels. The difference is in how they are acquired. Manufacturers of diamonds are trying to get away from the term "artificial". They want to call these new gems "cultured".

In an interesting sidenote: artificial diamonds may even replace silicon in microchips because diamonds will not overheat under almost any condition that a computer might be put through.

Next Page: What to Look for in a Diamond


1. NobelPrize.org



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