How Do You Make Lab Grown Diamonds

What Are Lab Grown Diamonds?

Lab grown diamonds, also known as synthetic or cultured diamonds, are real diamonds that are created in controlled laboratory environments rather than mined from the earth. These diamonds have the same chemical composition, physical properties, and optical characteristics as their natural counterparts—they are 100% real diamonds.

The key difference is their origin. While natural diamonds form over billions of years deep within the Earth’s mantle under extreme heat and pressure, lab grown diamonds are created in a matter of weeks or months using advanced technological processes that replicate these natural conditions.

Lab grown diamonds should not be confused with diamond simulants like cubic zirconia or moissanite, which merely look like diamonds but have different chemical compositions and properties. When you purchase a lab grown diamond from Emerson Fine Jewelry, you’re getting a genuine diamond with all the brilliance and durability of a mined stone.

The creation of these remarkable gems involves sophisticated scientific processes that have been refined over decades. There are two primary methods used to create lab grown diamonds: High Pressure High Temperature (HPHT) and Chemical Vapor Deposition (CVD). Both methods yield high-quality diamonds suitable for jewelry, though they differ significantly in their approach.

The history of lab grown diamonds dates back to the 1950s when scientists at General Electric created the first reproducible process for manufacturing diamonds. However, it wasn’t until recent decades that the technology advanced enough to create gem-quality diamonds suitable for jewelry. Today, lab grown diamonds represent one of the most exciting developments in the jewelry industry, offering consumers beautiful, ethical alternatives to mined diamonds.

The HPHT Method Explained

The High Pressure High Temperature (HPHT) method is the original technique for creating lab grown diamonds and mimics the natural conditions under which diamonds form in the Earth’s mantle. This process requires specialized equipment capable of generating extreme pressure and temperature conditions.

In the HPHT process, a small diamond seed (a tiny slice of an existing diamond) is placed in a growth chamber along with pure carbon in the form of graphite. The chamber is then subjected to pressures exceeding 1.5 million pounds per square inch and temperatures above 2,700 degrees Fahrenheit (1,500°C). Under these extreme conditions, the carbon melts and begins to form around the diamond seed, atom by atom, following the crystalline structure of the seed.

There are three main types of HPHT presses used in this process: the belt press, the cubic press, and the split-sphere press. Each varies slightly in design but achieves the same result—creating the perfect environment for diamond growth. The belt press was the original design used by General Electric, while the cubic and split-sphere presses were developed later to enhance efficiency and diamond quality.

The HPHT process typically takes several days to weeks, depending on the desired size of the final diamond. Once the growth period is complete, the rough diamond crystal is removed from the press and prepared for cutting and polishing.

HPHT diamonds often have distinctive growth characteristics that gemologists can identify. They typically grow in a cubic or cubo-octahedral pattern, and sometimes contain metallic inclusions from the flux material used in the growth process. However, modern HPHT diamonds can be virtually indistinguishable from natural diamonds without specialized testing equipment.

This method is particularly effective for creating colored diamonds by introducing specific elements during the growth process. For example, adding boron creates blue diamonds, while nitrogen creates yellow diamonds—offering beautiful options for unique custom engagement rings.

The CVD Method Explained

Chemical Vapor Deposition (CVD) is a more recent diamond-growing technology that has gained popularity in the gem-quality diamond market. Unlike HPHT, which mimics the natural formation process of diamonds, CVD takes a completely different approach.

In the CVD process, a thin slice of diamond seed (usually an HPHT-produced diamond) is placed in a sealed chamber. The chamber is filled with a carbon-rich gas—typically methane (CH₄)—mixed with hydrogen. The gas mixture is then energized, often using microwave energy, which breaks down the molecular bonds in the gas and ionizes it into plasma.

As the plasma heats up to about 1,400-1,800°F (750-1,000°C)—significantly lower temperatures than HPHT—the carbon atoms from the broken-down gas separate from the hydrogen and gradually deposit onto the diamond seed in crystalline form. The process is somewhat similar to how snowflakes build up during a snowfall, with carbon atoms “falling” onto the seed and building the diamond structure layer by atomic layer.

One of the advantages of the CVD method is that it operates at much lower pressures than HPHT, making the equipment less expensive and more accessible. The growth environment can also be more precisely controlled, allowing for the production of exceptionally pure diamonds with fewer defects.

CVD diamonds grow in a columnar structure, developing one layer at a time. This growth pattern can sometimes result in diamonds with different properties in different directions (anisotropy), though this is not visible to the naked eye and doesn’t affect the diamond’s appearance or durability.

After the initial growth phase, CVD diamonds are often subjected to a post-growth treatment using HPHT conditions to improve their color. This process can transform brown-tinged diamonds into colorless gems of exceptional quality, perfect for use in custom engagement rings and other fine jewelry pieces at Emerson Fine Jewelry.

The Diamond Growing Process

Regardless of which method is used—HPHT or CVD—creating a lab grown diamond is a precise, multi-step process that requires careful monitoring and control. Let’s walk through the general diamond growing process from start to finish.

Step 1: Seed Selection
Every lab grown diamond begins with a seed—a thin slice of an existing diamond that serves as the foundation upon which the new diamond will grow. The quality of this seed is crucial, as any defects in the seed may be replicated in the new diamond. Most manufacturers use high-quality HPHT synthetic diamond seeds that have been specifically created for this purpose.

Step 2: Preparation of Growth Chamber
The growth chamber must be meticulously cleaned and prepared to prevent contamination. For HPHT, this involves placing the seed and carbon source in the chamber along with metal catalysts that help facilitate the conversion of graphite to diamond. For CVD, the seed is mounted in the chamber, which is then vacuum-sealed before the carbon-containing gases are introduced.

Step 3: Initiation of Growth Conditions
In HPHT, massive presses generate the extreme pressure and temperature conditions needed. In CVD, microwave or hot filament energy is applied to create plasma and break down the gas molecules. In both cases, careful control of these conditions is essential for producing high-quality diamonds.

Step 4: Monitoring the Growth
Throughout the growth period, which can range from a few days to several weeks depending on the desired size and quality, technicians carefully monitor various parameters. The slightest fluctuation in temperature, pressure, or gas composition can affect the final product.

Step 5: Termination and Cooling
Once the diamond has reached the desired size, the growth process is gradually terminated, and the chamber is allowed to cool slowly. Rapid temperature changes could cause stress in the crystal structure and potentially damage the diamond.

Step 6: Extraction and Inspection
The rough diamond crystal is carefully removed from the growth chamber and undergoes preliminary inspection. At this stage, it often resembles a rough natural diamond and requires cutting and polishing to reveal its beauty.

This sophisticated process allows Emerson Fine Jewelry to offer stunning lab grown diamonds that are chemically, physically, and optically identical to mined diamonds—but with a known origin and without the environmental concerns associated with mining.

Cutting and Polishing Lab Diamonds

Once a rough lab grown diamond crystal is produced, it undergoes the same cutting and polishing processes as natural diamonds. This transformation from rough crystal to finished gemstone is a blend of art, science, and craftsmanship that dramatically affects the diamond’s final appearance and value.

Planning and Marking
First, skilled diamond planners analyze the rough crystal using advanced scanning technology to determine the optimal way to cut it. They consider factors such as maximizing carat weight, achieving the best clarity, and creating the most desirable shape. This planning phase is crucial, as any mistake could significantly reduce the value of the finished diamond.

Cleaving or Sawing
Next, the diamond is either cleaved along its natural planes or sawn with laser equipment or thin phosphor-bronze blades impregnated with diamond dust. This initial cutting separates the rough diamond into smaller, more manageable pieces that will become individual gems.

Bruting or Girdling
The diamond pieces then undergo bruting or girdling, where they’re shaped into round forms by grinding two diamonds against each other while they rotate in opposite directions. For fancy shapes like oval, pear, or custom engagement ring designs, different techniques are used to achieve the desired outline.

Faceting
The most intricate part of the process is faceting—cutting the small, flat surfaces (facets) that give diamonds their spectacular ability to reflect and refract light. A round brilliant cut diamond typically has 57 or 58 facets, each positioned at precise angles to maximize the diamond’s brilliance, fire, and scintillation.

Polishing
Each facet is carefully polished on a spinning wheel coated with diamond dust, the only substance hard enough to polish another diamond. This step removes any cutting marks and creates the smooth, glossy surfaces that allow light to enter and exit the diamond properly.

Inspection and Final Cleaning
The finished diamond undergoes thorough inspection to ensure all facets meet quality standards. It’s then cleaned in acids and other solutions to remove any remaining polishing compounds or other residues.

The cutting and polishing process is identical for both lab grown and natural diamonds, requiring the same level of skill and precision. However, because lab grown diamonds don’t have the same internal stress patterns as natural diamonds, cutters sometimes have more flexibility in how they approach the cutting process, potentially allowing for more optimal cuts.

At Emerson Fine Jewelry, we select only beautifully cut lab grown diamonds for our collections, ensuring that each stone displays the exceptional brilliance and fire that diamond lovers expect.

Certification and Grading

Like natural diamonds, lab grown diamonds undergo professional grading and certification to assess and document their quality characteristics. These certifications provide assurance to consumers about what they’re purchasing and enable meaningful comparisons between different diamonds.

Major Grading Laboratories
Several respected gemological laboratories now offer specialized grading reports for lab grown diamonds. These include the International Gemological Institute (IGI), Gemological Institute of America (GIA), and GCAL (Gem Certification & Assurance Lab). Each lab uses slightly different formats and terminology, but all evaluate the same key quality factors.

The 4Cs Assessment
Lab grown diamonds are graded using the same “4Cs” framework used for natural diamonds:

• Cut: Evaluates how well the diamond has been cut and polished, including its proportions, symmetry, and ability to reflect light.
• Color: Assesses the presence or absence of color, with completely colorless diamonds being the most valuable for white diamonds.
• Clarity: Examines the presence of internal characteristics (inclusions) and surface features (blemishes).
• Carat Weight: Measures the diamond’s weight, where one carat equals 0.2 grams.

Special Designations
Certification reports for lab grown diamonds include clear identification of their laboratory origin. The GIA, for example, uses the term “Laboratory-Grown” prominently on their reports for these diamonds and includes the statement: “This is a man-made diamond produced by CVD (Chemical Vapor Deposition) or HPHT (High Pressure High Temperature) growth processes and may include post-growth treatments to alter the color.”

Growth Method Identification
Many certification reports also specify whether the diamond was created using the HPHT or CVD method, as each process can impart slightly different characteristics to the final product.

Inscriptions
Most certified lab grown diamonds receive a laser inscription on their girdle (the outer edge) that includes the report number and sometimes an explicit lab grown designation. This inscription is microscopic and doesn’t affect the diamond’s appearance but provides a permanent means of identification.

At Emerson Fine Jewelry, we ensure that all our lab grown diamonds come with proper certification from respected grading laboratories. This certification gives our customers complete transparency about what they’re purchasing and confidence in the quality of their investment, whether for