From Carbon to Carats: How Are Diamonds Formed?

November 20th, 2023 / Alese Oldenburg

Mined diamonds are not the only choice anymore. Today’s market features a variety of stone options, from lab-grown diamonds to diamond alternatives. Each one is created differently, and because of that, may feature different qualities. Physical characteristics, optical brilliance, price point, and origin are the most common differences between these stones. Before purchasing an engagement ring or piece of fine diamond jewelry, know what sets the three most common diamond and diamond alternatives apart.

About Mined Diamonds

Mined diamonds, born from the Earth’s geological ballet of heat and pressure, hold a captivating origin story. These natural marvels, crystallized carbon structures, take shape beneath the Earth’s surface over eons, emerging through natural events like volcanic eruptions. The journey from subterranean depths to the surface culminates in the meticulous extraction process known as mining. However, the allure of mined diamonds comes with ecological and ethical complexities. The environmental toll is stark, with a single one-carat diamond requiring the displacement of 88,000 to 176,000 pounds of earth. The repercussions extend beyond land disruption, as diamond mining contributes to pollution, sea habitat destruction, and the potential for harmful acid rock drainage that affects groundwater and life dependent on it.

Beyond environmental concerns, the diamond mining industry grapples with human rights issues, including inhumane treatment of workers, the use of child labor, and heightened health risks. Unveiling this darker side encourages a critical examination of the impact of mined diamonds on both our planet and its inhabitants. Intriguingly, the tradition of using mined diamonds in engagement rings only gained prominence in the early 1900s. The De Beers “A Diamond is Forever” campaign, a marketing triumph by N.W. Ayer, transformed diamonds into symbols of eternal love, creating a demand where none existed before. Today, this historical marketing legacy continues to influence the choices of couples worldwide.

How are Diamonds Formed?

A mined/natural diamond is a crystallized carbon structure that is formed beneath the earth’s surface over millions (or sometimes billions) of years under the perfect conditions of heat and pressure. The diamonds are brought to the surface during natural events (like volcanic eruption impact sites) and then mined from the land.

Environmental Impact of Mined Diamonds

By now, you may have heard that mined diamonds come from a very dark place, and we’re not talking about the ground. A one-carat mined diamond costs the mining plant between 88,000 and 176,000 pounds of earth. The pollution that diamond mines cause destroys sea habitats and can even cause acid rock drainage that leaks into groundwater, contaminating all living things that depend on the water source. The diamond mining industry impacts not only the environment but human rights as well. The industry is known for the inhumane treatment of workers and even child labor, not to mention the higher risk of health-related issues.

Another intriguing fact about mined diamonds is that they weren’t a popular commodity for engagement rings until the early 1900s when diamond corporation De Beers first ran their “A Diamond is Forever” advertising campaign, executed by ad agency N.W. Ayer. This campaign is known as one of the most successful campaigns because it created demand out of a non-existent market. Today, this psychological necessity has continued to be practiced by the majority of couples.

Chemistry of Diamond Formation

Let’s delve a bit more into the details of how natural diamonds are made. Diamonds are formed naturally in the earth’s mantle under conditions of extreme temperature and pressure. These conditions occur in limited zones about 100 miles or more below the earth’s surface, where temperatures are at least 2000 degrees Fahrenheit and pressure is, or exceeds, 725,000 pounds per square inch. This is the critical temperature and pressure needed for natural diamond formation and stability. The carbon atoms then bond together under the extreme environment, forming diamonds. This is how colored diamonds are created as well.

Diamonds formed and stored in these limited zones of the deep earth are delivered to the earth’s surface through volcanic eruption. These eruptions tear out pieces of the upper mantle and carry them to the surface. Only volcanoes that erupt from deep depths will cause this to happen, the average volcano does not.

Do Diamonds Come from Coal?

A common misconception is that coal is correlated with diamond formation. Coal is also made of carbon, which makes sense why there would be confusion. However, it also includes many other substances, making it a sedimentary rock. Coal originates from plant debris, fungi, and even bacteria. The impurities alone prevent coal from becoming a rough diamond. It is also rarely buried to depths greater than two miles, which makes it very unlikely that it would have been moved from the earth’s crust down to such an extreme depth. Instead, the carbon source for diamonds is most likely carbon trapped in the earth’s interior.

About Lab Diamonds

Are lab diamonds real? Yes, lab diamonds are the same as mined diamonds, except they are grown in a lab instead of mined from the deep earth. They are made of a crystallized carbon structure, which means they have the same chemical, physical, and optical properties as mined diamonds. The only difference between lab diamonds and mined diamonds is their origin.

Because there is no diamond mining involved with the creation of lab-grown diamonds, they are better for the environment and better for you (yes, they even cost less). Carbon emissions and other environmental hardships are greatly reduced because mining is eliminated. With lab diamonds, you get the same quality stone for around 20-30% less, and reassurance that your purchase doesn’t contribute to the blood diamond trade.

Lab diamonds are created under the same conditions as mined diamonds, which is why each one will turn out completely different. Due to this, they are graded on the same 4Cs of Diamond Quality. This grading system rates a stone’s overall quality, which determines how much a diamond is worth.

How are Lab Diamonds Made?

Lab diamonds are grown from a carbon seed, like flowers in a greenhouse. Because technology has evolved so much, scientists are able to replicate the conditions in which diamonds form naturally, with two main methods: Chemical Vapor Deposition (CVD) and High-Pressure High Temperature (HPHT).

Can Humans Make Diamond?

The short answer is yes, humans can make man-made diamonds or lab grown diamond stimulants. The newer and more adapted method is through Chemical Vapor Deposition (CVD). In the process for CVD diamonds, a small slice of diamond seed (which is often an HPHT-produced diamond) is placed in a chamber and heated to extreme temperatures, much like a rough diamond would undergo in the ground. The chamber is then filled with gases that help form the diamond, like methane. The gases are ionized into plasma using lasers. The ionization breaks the molecular bonds and the carbon adheres to the diamond seed, slowly crystallizing. The final result is a crystalized carbon structure, exactly the same as a mined diamond.

The HPHT diamonds method is still widely used and results in the same product. One of three manufacturing processes is used in this method: a belt press, cubic press, and split-sphere press. All three of these processes create an environment of high pressure and temperature. In this method, a diamond seed is placed into carbon. Using one of the three methods, it is then exposed to temperatures around 2000 degrees Fahrenheit and pressurized to approximately 1.5 million pounds per square inch. The carbon melts and starts to form a diamond starter seed. Once the cooling process is finished, the result is a crystalized carbon structure.

About Diamond Alternatives

A diamond alternative is a simulant stone that resembles diamonds but is chemically distinct. There are many options on the market today, such as cubic zirconia, morganite, and amethyst. Each stone features completely different characteristics as they are made out of different materials. CZ is one of the most common diamond alternatives on the market, commonly seen in inexpensive jewelry. Although a well-cut CZ may look similar to a diamond at first, it is much more porous than a diamond, which causes it to absorb contaminants and dull over time.

The most superior diamond alternative on the market is the Nexus Diamond™ alternative, which most closely simulates the look, feel, and wear of a flawless mined diamond, with two exceptions- it costs significantly less and is perfect in every way. Nexus Diamonds are made of a proprietary formula and patented coating material which causes them to reflect light at a much closer rate to diamonds than all other simulants. The final product is a stone that is harder, heavier, and less porous than other alternative stones, making it much more similar to a colorless, flawless diamond.

Formation of Nexus Diamond™ Alternatives

The diamond simulant creation process begins similarly to the lab diamond process. A proprietary blend of elements is heated to extreme temperatures. The elements then reach a molten state. The next step is to carefully cool the molten matrix in controlled stages that allow crystals to form. This is one of the most critical phases in creating diamond simulants. If cooled too slowly, crystals will not form; if cooled too quickly, crystals will shatter.

Following the cooling stage, a solid object containing both crystallized and non-crystallized material will be left. The crystals are a hard, heavy, dense material that closely resembles the look of an uncut diamond crystal. The crystals are inspected for quality in a similar way to how rough diamonds are inspected and graded using the 4Cs.

After the stones are rough cut, they contain no inclusions or other flaws. They are sorted and moved to the final cutting stage. Because each crystal is flawless, our master cutters can be much more precise, because they are not trying to cut around and hide flaws. This means all of our diamond simulants are cut to Ideal standards, which produces the desirable “Hearts & Arrows” effect found in the finest mined diamonds on the diamond cut scale. Our diamond simulants are then coated in a patented coating material, which seals them completely and makes them even harder and non-porous. The coating finishes the diamond simulant creation process.

Comparing Mined, Lab, and Diamond Alternatives

Each of these stone options is created in different ways, which results in different characteristics. It’s important to know the other main differences between these three options as well before making a decision.

Mined vs. Lab Diamonds

The differences between the two stone options come down to price point, environmental damage, and ethical concerns.

Because lab diamonds are fairly new to the market, they are currently less expensive than mined diamonds. The average lab diamond averages around 20-30% less than a comparable mined diamond. This means you can get the exact chemical, optical, and physical quality that you would from a mined diamond, for up to 30% less. Or, you could use that savings to afford a higher quality stone that isn’t contributing to the damage of the earth’s crust.

With lab diamonds, environmental concerns are almost eliminated. The act of mining produces horrendous and irreversible ecological damage to the earth’s mantle, which is not seen in lab-grown diamonds. In addition, the carbon footprint left behind from mining is greatly reduced, and maybe a fraction of what is caused by mined diamonds.

Lab diamonds are also not associated with the ethical concerns inherent in mined diamonds. Companies cultivate good working conditions, unlike the blood diamond trade where working conditions are akin to slave labor to create what is considered a conflict diamond. There is also no concern about employees being at risk for mining-related accidents.

Lab Diamonds vs. Diamond Alternatives

Comparing lab diamonds and diamond alternatives primarily involves a matter of composition. Diamond alternatives are not made of a crystalized carbon structure, making them chemically different than diamonds. This also has a resulting impact on the quality of the stones in ways.

Lab diamonds are graded using the 4Cs of Diamond Quality, just as mined diamonds are. Each diamond deposit will turn out differently due to the chemical composition, and because of that, so will the quality.

• Clarity: A stone’s grading on the diamond clarity scale will depend on how many and the position of its mineral inclusions and blemishes. Since a perfect stone is extremely rare, most stones will have some inclusions, but whether they are noticeable to the naked eye will determine their price point.
• Cut: All lab diamonds can be cut differently, and will depend on the company who sells them. Some companies exclusively offer higher cut grades, meaning stones that are cut to an Ideal standard will allow them to emit the most brilliance and fire. The higher the grade, the more light the stone will reflect.
• Color: Although all diamonds (lab or mined) are made of a crystallized carbon structure, a stone’s chemical makeup can differ slightly due to trace elements other than pure carbon during the formation. This can cause stones to show slightly yellow in color. All stones are measured on the diamond color scale, and the less color a stone shows, the more valuable it will be.
• Carat: Diamonds vary in weight. In a lab, diamonds are in a controlled state and can be grown for a longer period of time to reach a larger size. The larger a stone is, as indicated on the diamond carat chart, the higher the price point will be.

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Diamond alternatives have a slightly different quality to them. Nexus Diamond™ alternatives are also graded on the 4Cs of Diamond Quality but are created to be more perfect than the average lab or mined diamond.

• Clarity: The Nexus Diamond™ alternative is rated Internally Flawless, meaning it has no mineral inclusions or blemishes due to its chemical makeup.
• Cut: All Nexus Diamond™ are Ideal Cut, which means they emit the most amount of brilliance and fire.
• Color: The Nexus Diamond™ is D color, meaning it is completely colorless.
• Carat: Just like a diamond, the Nexus Diamond™ alternative varies in carat weight. The difference is that it costs up to 80% less than mined diamonds. The average one carat engagement ring set with the Nexus Diamond™ alternative costs around $1,300*.

While choosing from the different types of stones for rings and settings might be confusing, finding the right diamond or diamond alternative doesn’t have to be. When you decide to embark on the journey of finding the best stone for your diamond engagement ring or other fine jewelry, the best route is to be informed. By taking all of the information about how diamonds are made and how that impacts quality, appearance, and price, you will be equipped to find the perfect diamond alternative for you.

*Diamond Nexus strives to provide valuable information while being clear and honest about our products. The Nexus Diamond™ alternative is a patented lab-grown stone that, among all simulants, most closely imitates the look, weight, and wear of a mined diamond, with two exceptions – it is absolutely perfect in every way, and it costs significantly less. Price points and environmental facts expressed in this blog were taken from popular online retailers and may vary. Learn more about the environmental impact of mining by visiting our blog.