How Are Lab Grown Diamonds Made?
The first diamond was discovered in 1797 and likewise, fake or faux diamonds are nothing new. There has been a market for stones that look like diamonds for centuries simply because consumers want the look but are not able or prepared to pay the price for genuine mined diamonds.
Most people know about diamond simulants. Cubic zirconia jewelry has been around for a long time and in recent years moissanite has joined the list. More recently, however, there has been an increasing number of jewelers selling lab-grown diamonds.
Lab-grown diamonds are being presented in jewelry and as loose diamonds in exactly the same way as natural diamonds.
What Are Lab Grown Diamonds?
Lab-grown diamonds are also known as cultured diamonds, lab-created diamonds, man-made diamonds, and engineered diamonds.
As their name states, these are diamonds that are manufactured in a laboratory rather than being mined from the ground.
The process replicates the formation of natural stones which happens in the mantle, between 90 and 150 miles below the crust (the Earth’s surface). When carbon (and carbon dioxide) deposits are subjected to extremely high pressure (about 727,000 pounds per square inch) and temperatures (2,000+ degrees Fahrenheit), they compress and diamonds are formed. This process can take millions to billions of years to form. Diamonds are usually moved to mineable depths by volcanic explosions.
A Brief History of Lab-Grown Diamonds
The race to produce synthetic diamonds began very soon after the first stones were discovered and there is anecdotal but unproven evidence suggesting that there was some success between 1879 and 1928.
In 1892, Henry Moissan, a Parisian scientist and later, Nobel laureate, hypothesized that diamonds could be made by subjecting molten iron to pressure to form crystallized carbon. Using an electric arc furnace that could reach temperatures of 3,500°C, he managed to produce tiny artificial stones. Moissan also discovered moissanite (in 1893) which he initially mistook for diamond (it is actually silicon carbide). As already mentioned, moissanite is used today as a diamond substitute.
Work on the processes by various unconnected parties was interrupted by the Second World War but it is an accepted fact that the first batch recognized as lab-created diamonds was produced by General Electric in 1954. The project was codenamed Project Super pressure and was led by chemist H. Tracy Hall.
It used a high-pressure belt press to apply pressure of 100,000 atm and temperatures of 1,600º C (2,912º F) to small seed crystals of graphite combined with iron, nickel, and cobalt to form a diamond. These first synthetic stones were tiny and of very poor quality but were of use in industrial processes.
It is also known that around the same time ASEA, (the Swedish electrical utility) also managed to create lab diamonds, but their discovery was kept secret until the 1980s.
Over time, the processes have evolved and improved. The HPHT (high pressure, high temperature) method was joined by CVD (chemical vapor deposition).
These refined and improved techniques have enabled the production of man-made diamonds of up to 12 carats and seen a big increase in quality.
How Are Lab Grown Diamonds Made?
The various processes used are all designed to replicate the environmental conditions in which natural diamonds form.
There are two most commonly used processes: the high-pressure high temperature (HPHT) method and the chemical vapor deposition (CVD method).
The HPHT Method
Ths process begins with a small diamond seed. This is placed into a piece of carbon which is then subjected to extreme pressure of around 1.5 million pounds per square inch. The pressure is applied using either a cubic press, belt press, or BARS (split-sphere) press. The carbon is also exposed to a temperature of over 2,700 degrees Fahrenheit. Together, the heat and pressure melt the carbon atoms around the seed forming a diamond as it is cooled.
The CVD Method
CVD is most commonly used for high-quality, wearable gems. This process also begins with a small diamond seed and quite often it is an HPHT diamond. Rather than using presses, the CVD process uses a sealed chamber filled with carbon-rich gases (such as methane to which hydrogen is added) to heat the seed to more than 1,400 degrees Fahrenheit. With technology similar to microwaves or lasers, plasma is formed as the gases are ionized. What happens is that reacting to the heat, the molecular bonds of the gas are broken producing microlayers of pure carbon film that stick to the seed. The atoms fuse together, building up into a diamond crystal structure solid. to form a new diamond. The resulting unbreakable, cohesive material is a CVD diamond.
Both methods produce a stone with exactly the same physical properties, optical properties, and chemical properties as a natural diamond.
Sometimes (in both methods), the formed stone has more heat and/or pressure applied in order to produce a higher quality stone.
Just like real diamonds that come in colors other than white, colored diamonds can be produced in the laboratory. Growing diamonds in different colors involves the addition of minute amounts of trace elements during the process.
As in nature, there are no specific composition ratios or measurements of the elements added to produce the color, so each stone has its own unique color.
Elements like sulfur, nitrogen, and boron produce colors of blue, green, and yellow. The difference between natural stones and lab stones is that the number of trace elements can be adjusted to produce fancy colors that are not seen in natural diamonds.
It can take millions or even billions of years for natural diamonds to be formed but diamonds can be grown in the lab in less than a month. Yellow and blue diamonds can be grown in 5-10 days while it can take 2+ weeks to grow a 1-carat white diamond. Rushing the process can result in fractured crystals.
After formation, lab stones are sent to gemologists for cutting and polishing in the same way as natural, rough diamonds.
What’s the Difference Between Mined Diamonds and Lab Grown Diamonds?
This is the big question to which everyone wants to know the answer.
The reason for the increasing interest and proliferation in the availability of lab-grown diamonds is because lab stones are “real” diamonds.
Diamonds grown in a laboratory are only distinguishable from mined diamonds with specialized equipment that is able to examine the internal structure to detect any differences in the way the crystals have grown and the trace element content.
There is no visible discernible difference to the naked eye between lab-grown diamonds and natural diamonds. If you buy a beautiful diamond engagement ring set with grown stones, only you and the jeweler will know. There will come a time when this issue won’t matter and lab-grown stones will be universally accepted as things of beauty in their own right and not just something that replicates quality diamonds.
To put to bed the issue of whether lab-grown diamonds are real diamonds, we can look to the Federal Trade Commission. The FTC definition of a diamond is “pure crystallized carbon in the isometric cubic system” and this applies whether the diamond is natural or lab-grown. This confirms that when stones of crystallized carbon have the same chemical, physical and optical properties, and regardless of the origin, they are gemstones known as diamonds!
Because of this definition, lab-grown stones are subject to the same diamond grading rules as mined diamonds across the diamond industry.
Lab-Grown Diamonds Certification and Grading
All diamonds should have a grading report. This report details the 4Cs - color, cut, clarity, and carat. It is a confirmation of the quality of the stone you have purchased. Mined diamonds will be certified by the GIA (Gemological Institute of America) whereas lab-grown diamonds will most commonly carry reports from the IGI (International Gemological Institute) or GCAL (Gem Certification & Assurance Lab. The reports will state that the diamond has been produced in a laboratory.
Reasons to Choose Lab-Grown Diamonds Over Natural Diamonds
As well as being equally beautiful as natural stones, there are a number of benefits of lab-grown stones that can be classed as financial, ethical, and environmental. As consumer views change, these benefits are growing insignificance.
Lab-Grown Diamonds Are Less Expensive Than Mined Diamonds
Generally, traditionally mined diamonds are 30 to 50 percent more expensive than lab-grown diamonds. This means you can get a greater carat weight or a higher quality stone with lab-grown. You can purchase a sparkling and stunning diamond engagement ring with a more impressive and high-quality center stone! As the technology continues to improve and processing times reduce, the price difference is only likely to increase.
Lab-Grown Diamonds Have Better Quality for the Price
Because the lab process is strictly controlled, there is a greater propensity for higher quality and fewer defects. With rough diamonds, the quality can’t be seen immediately and imperfections such as inclusions may not be visible until the cutting process starts.
Lab-Grown Diamonds Are More Socially Responsible
There are ethical and humanitarian concerns over natural stones. Historically and contemporaneously, the diamond mining industry has been linked with poor working conditions and human rights violations. There’s also what is known as blood or conflict diamonds. Some of the most important diamond mine locations are in countries in economic strife or experiencing civil or guerilla war. Diamonds are used to fund armed conflicts. There is no such issue with lab diamonds because every stone is traceable back to the laboratory that produced it.
Lab-Grown Diamonds Have a Smaller Environmental Impact
Diamond mining causes environmental chaos by destroying habitats and altering the landscape. It may take sifting through 88 and 176 thousand pounds of the earth to find just a single 1-carat diamond. The laboratory process is also more sustainable than mining. The consistent message from major diamond companies (like De Beers) that diamonds are a scarce resource (therefore enabling them to keep the prices high) is now dispelled by the fact that high-quality diamonds can be produced in a laboratory. Diamonds are not rare.
The Takeaway
We have learned that
- Lab-grown diamonds are created by two different processes
- Lab-grown diamonds are real diamonds
- Lab-grown diamonds are cheaper than mined diamonds and of equal or higher quality
- Lab-grown diamonds are more ethical, environmentally friendly, and sustainable than natural diamonds.