History Of Man Made Diamonds

Henri Moissan (1852-1907) received the Nobel Prize in Chemistry in 1906.  In 1892 theorized that by crystallizing carbon with pressure and heat from molten iron he could make diamonds.  The then set out to prove his theory by designing and building an electric-arc furnace.  He subsequently was able to product several tiny stones that had the same properties as mined diamonds.  Thus the start of the man made diamond race was born.

The experiment was successfully repeated by Ruffin in 1917 and again by Dr Willard Hershey in 1926.  The diamond that was created by Dr Willard Hershey is on display in Kansas at the McPherson Museum.  Despite the earlier success, the following experimenters had great difficulty in reproducing the required temperatures and pressures needed by the process and some of the experimenters even lost their lives to explosions. 

In 1941 General Electric was able to produce a one carat diamond but of very poor quality.  It was not until 1954 that General Electric was able to produce commercially synthesis diamonds of a size and quality to be used in the industrial abrasives market.  Today over 600 metric tons of commercially produced diamonds are produced for the industrial abrasives market and about 26 metric tons of mined diamonds are produced for gemstone market yearly.

Today there are two methods used to produce gem quality diamonds.  The first is the High Pressure High Temperature (HPHT).  If pure carbon in put under pressures of 50,000 atmospheres and temperatures between 1100, and 1400 degrees Celsius will reproduce the environment that creates diamonds inside the Earths core.

Companies like Gemesis, New Age Diamonds, Adia Diamonds and Tairus all utilize the HPHT method of producing gem quality man made diamonds.  Clear or White diamonds must be produced in an environment that is free of impurities like nitrogen and boron which makes them very difficult and costly to produce.  Most diamonds created by the HPHT method will contain some color.  Yellow or orange tint occurs when nitrogen atoms replace 5 or more carbon atoms out of each 10,000 atoms.  At a level of one or a few boron atoms for every million-carbon atom is replaced, an attractive blue color results.

The second method used to produce gem quality diamonds is called Chemical Vapor Deposition (CVD).  When pure carbon and hydrogen is heated to about 1,8000 degrees Fahrenheit a plasma cloud is formed.  As the plasma cools carbon will rain out of the mixture and carbon atoms will be deposited on wafer seeds.  The wafers will grow at about 1/2 a millimeter a day.  The ability to control the injection of impurties allows a greater measure of control in the final diamond composition than the HTHP method.  Apollo Diamond uses the CVD method of producing the larger and more expensive man made diamonds.

Man-made diamonds are very difficult to distinguish from natural ones.  A trained jeweler could tell the difference if he could detect the different growth patterns and the lack of inclusions.  Inclusions are the tiny bits of material that are usually imbedded in a natural diamond and are considered a flaw.  The ability to be able to control the amount and type of inclusion is vital to the ability of the man made diamond to be used in semiconductor applications which in turn will lead to the next generation of computer chips.