How Are Lab Grown Diamonds Made?

A rough lab grown diamond

Lab-grown diamonds are one of the marvels that came out of the 20th century, and are today rocking, rolling, and rocketing to increasing popular demand, especially for diamond engagement rings. 

But lab-grown diamonds have a significant PR problem to overcome, and widely dispersed misinformation to counter. 

Here in this article, we will cover how they are made, and why they are worth your time and consideration, not to mention, a place on your finger in your engagement ring, or other jewelry. 

Some of the specific questions we will answer are:

  • What are lab-grown diamonds?
  • How are lab-grown diamonds made?
  • What are the advantages and disadvantages of lab-grown diamonds?
  • Are lab-grown diamonds as hard as natural diamonds?
  • How are they graded and do lab-grown diamonds pass diamond testers?
  • Are lab-grown diamonds valuable?

What are lab-grown diamonds?

Diamonds are pure carbon crystals in a specific atomic structure- a tetrahedral atomic latticework. Lab-grown versions of these are chemically, physically, and optically the same as mined diamonds. They can have the same quality, the same fire, and the same clarity grades as mined diamonds.

At the end of the day, the only difference between diamonds grown in a lab and natural diamonds is their origin and their price. Diamonds created in a lab can be produced and brought to market at a fraction of the economic, environmental and social cost of mined diamonds. 

Are lab-grown diamonds real diamonds? 

Yes, man-made diamonds are real diamonds. They are carbon crystals atomically equivalent to naturally forming, mined diamonds. They have the same chemical and optical properties, and for all intents and purposes are exactly the same.

How are lab-grown diamonds made?

Man has tried to create diamonds for centuries. Most of the "synthetic diamonds" that resulted from early experiments were not real diamonds at all.

Real diamonds were first grown in the 1950s by GE in secret experiments. The process developed then, called HPHT (High Pressure, High Temperature) replicates conditions in which diamonds form naturally. Another process that began development around the same time is called CVD, chemical vapor deposition.

An open HPHT unit

HPHT: High Pressure High Temperature

In HPHT, pure carbon, often in the form of graphite, is planted with a seed diamond. It is on this very tiny piece of diamond crystal that the rest of the diamond will grow. Seed diamonds can be natural or from a previously grown lab diamond.

The carbon with its seed crystal is set in a cubic press, a chamber under immense pressure and heat, replicating conditions deep in the earth’s crust where some diamonds form naturally.

Under this incredible strain of extreme pressure and heat, the atoms in the graphite or other pure carbon bond with the atoms in the diamond seed, growing the tetrahedral lattice outwards and producing a newly formed diamond crystal. It takes a few weeks to grow diamonds this way, but its simplicity makes it a popular production method.  

CVD: Chemical Vapor Deposition

A more complicated technology, CVD, chemical vapor deposition, is actually a very cool bit of science. 

Instead of using extreme temperatures and pressure, as in HPHT, in the CVD diamond process, carbon-rich gases such as methane or carbon dioxide, are irradiated with microwaves in a vacuum chamber. The carbon atoms in the carbon-rich gas, broken down and charged up, fall like snow on a small diamond seed in the chamber, where they crystallize in a tetrahedral lattice and produce a new diamond.

This increasingly popular method uses much less energy, is faster than HPHT, and is more responsive to influences that can produce bigger stones, stones of greater quality, or stones with extra properties, such as fancy colors or specific conductivities. 

What are the disadvantages of lab-grown diamonds?


Rarity: Currently the created diamond market accounts for about 7-10% of global sales. So at the moment, not everyone has access to them. However, it is growing at a faster pace than the mined diamond market, so lab-created diamonds may be more widely available in the future. 

Size: It's only a matter of time before diamonds grown in laboratories reach the whopping sizes of some natural stones. At the moment though, the only way to get very large stones is via the natural diamond market (for millions of dollars.)  

Right now the current title holder for the world's largest lab-grown diamond is the emerald-shaped, “Pride of India,” which weighs in at about 30 carats. While it is a very large diamond, it pales in comparison to the size of some mined diamonds, which can be hundreds and even thousands of carats.

Color: At the moment, most lab-grown diamonds are white stones, and while some fancy-colored diamonds are produced, it will be a few years at least, before the large-scale availability of a wide range of fancy-colored lab-grown diamonds.  

Resale Value

It's true that lab-created diamonds do not resale to the market at their original price, though neither do natural, mined diamonds, which resale at only 30-70% of their original market value. While that is still more than lab-grown diamonds, in general, it’s not wise to invest in diamonds. Buy them for their splendor and light, not their resale value. 

What are the advantages of lab-grown diamonds?

Lab diamonds present many advantages to the consumer. 

Cost of Lab Created Diamonds

Carat per carat, lab-grown diamonds are normally less expensive than their mined counterparts, averaging around 50-70% less than the price of natural diamonds. 

They are often more environmentally friendly, using a fraction of the energy, water and land for production and to get to market. 

Mined diamonds present many environmental and economic risks that lab-grown diamonds never have to consider. For example, most diamond mines are located in remote, sometimes quite inhospitable regions far, far away from cutting and selling centers.

They can sometimes use up the entire water resources available, leaving nothing for the region's normal and native inhabitants, whether they be people or plants. In cultured diamond production, much less water is used and that water is normally recyclable. Very little land is disturbed, and laboratories use much less energy than many mines. 

Diamond ore must be extracted, then processed to remove the stones, normally 1 carat per 250 tons of ore. The roughs (uncut diamonds) are then shipped to cutting centers and then transported to wholesale centers, before being dispersed to resale ventures. 

Lab-grown diamonds are often grown and cut in the same facilities, often deliberately located near major wholesale centers, so as to avoid all the costs associated with extended shipping and handling.

Lab grown diamonds are conflict-free and child labor free

Lab grown diamonds are conflict-free, and child labor free, since they are largely produced by countries not in conflict, and use skilled and highly skilled labor, largely highly educated scientists and engineers. The only children that you would find in a diamond-growing lab would be schoolchildren on a field trip to learn about lab-grown diamonds.

Conflict diamonds are defined by the Kimberley Process as mined diamonds whose sale goes toward the armed insurrection of militant groups against a sitting government. However, it does not regulate diamonds whose sale allows a sitting government to wage conflict against its own or other peoples, or militants not engaged in conflict with a sitting government; nor does it regulate forced labor or child labor. 

As much or more than 30% of the mined diamond market is suspected of being mined with forced or child labor, or to be a conflict diamond not regulated by Kimberly. This is especially true of diamond mining which supports aggressive and deadly conflicts between independent countries. 

Are lab-grown diamonds as hard as natural diamonds?

Yes, lab-grown diamonds are exactly as hard as mined diamonds. Since they are the same form of carbon crystal, with the same density, they produce the same result on the Mohs Hardness scale, earning them the same grade of 10 as natural diamonds. 

Do lab-grown diamonds pass diamond testers?

Yes, lab-grown diamonds will pass diamond testers since they have the same thermal and electrical conductivity as natural diamonds. Today almost all diamond testers measure the electrical and thermal conductivity of the gem in question, and so lab-created diamonds test as diamonds. However, in the past testers that only measured one or the other may have identified lab diamonds as moissanite or other fake diamonds.

Can you tell the difference between a natural diamond and a cultured diamond?

Yes, but only with specialist equipment. Even experienced and expert professional gemologists cannot tell the difference with the naked eye, or even with basic equipment like a jeweler's loupe.

The exception to this is a diamond that has already been certified by a gemological institute, which has put a tiny laser inscription on the girdle of the diamond. These inscriptions carry the letters "LG," for lab-grown. You can view this inscription with the help of a jeweler's loupe.

Grading lab-grown diamonds

GIA, the Gemological Institute of America, and IGI, the International Gemological Institute, evaluate both mined diamonds and those created in labs. They produce diamond certification for each gem they evaluate. In the gem certification report, they include the origin of the diamond, whether it is mined or man-made; the 4Cs: clarity, cut, color and carat weight; the diamond's proportions, and other information.

IGI lab grown diamond certification

What Are lab-created diamonds worth?

Lab-grown diamonds have an intrinsic value because they are real diamonds. Similar to natural diamonds they will resale for a portion of their original value.

Most importantly, they become more and more valuable to you when they are imbued with a lifelong saga of meaningful personal experience.  After all, your diamond engagement ring is worth more than the materials it's made of- its worth is directly connected to your relationship.

H3. Lab Grown Diamonds at Michael Gabriels 

Lab grown diamond girdle held up to viewing in a loupe

At Michael Gabriels, we only sell the highest quality lab-grown diamonds, all of which are certified by GIA or IGI. Most of our diamonds are CVD, but we do get in some very high-quality HPHT stones as well. We are ready to answer any questions that you may have, from growing diamonds to setting them in customized or fully bespoke pieces of jewelry. All of our pieces are made right here in New York City by our expert craftspeople. You can contact us on Instagram or our website.