How Are Lab Grown Diamonds Made?

There are two methods used to create lab grown diamonds: CVD (Chemical Vapour Deposition) and HPHT (High Pressure High Temperature). Both create beautiful, high-quality lab grown diamonds.

What to Know Before Buying Lab Grown Diamonds

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Why Should I Consider Lab Grown Diamonds Over Natural Diamonds?

Finding the right diamond for you or for someone else can be overwhelming. Now there is the added decision to make between a lab grown diamond or a natural diamond.

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The 4Cs

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Introduction

There are two methods used to create lab grown diamonds: CVD (Chemical Vapour Deposition) and HPHT (High Pressure High Temperature). Both methods are successful in creating beautiful, high-quality lab grown diamonds that are just as real as those found from mining.
HPHT diamonds are created by adding a pre-existing diamond fragment and pure carbon within a metal tube and exposing it to high levels of heat and pressure. Over time the carbon breaks down and crystallises into a diamond. CVD diamonds also begin as a pre-existing diamond fragment which is placed into a chamber and exposed to carbon-rich gas at extremely high temperatures. In just a matter of weeks, the carbon gas ionises and surrounds the original piece of diamond, eventually creating a fully formed cultured diamond.

How Are High Pressure High Temperature Diamonds (HPHT) Created?

1. High Pressure High Temperature Diamonds also require a small diamond “seed” which is placed within a containment. It is typically around 300 microns thick and around 10x10mm.
2. The cube is put under the same amount of pressure that a natural diamond would experience in the Earth’s surface which is typically above 870,000 pounds per square inch
3. The cube is also heated through electric pulses between 300 to 1,600 degrees Celsius which leads the carbon to crystallise
4. In a matter of weeks, a rough lab grown diamond is created, typically in a cuboctahedron shape
5. The cultured diamond is removed from the containment cube and cut with laser precision into the requested shape
7. The diamond is graded by institutes like the GIA to access its colour, cut, clarity and carat weight

How Are Chemical Vapor Deposition Diamonds (CVD) Created?

1. The Chemical Vapor Deposition system begins with a diamond fragment, often called a diamond “seed”. It is typically around 300 microns thick and around 10x10mm. It’s also usually taken from a pre-existing lab grown diamond
2. The diamond fragment is thoroughly cleaned and placed into a vacuum chamber
3. The chamber is then filled with carbon rich gas and heated to around 800 degrees Celsius
4. The gas reacts by breaking down, covering the diamond fragment and binding to it
5. After a couple of weeks, the gas will have continued to break down and coated the diamond fragment further, layering up and building to its desired carat weight
6. The lab grown diamond is created and will at first look like a square cube. It is then that the diamond is cut with laser precision into the requested shape
7. The synthetic diamond is graded by institutes like the IGI (International Gemological Institute) and GIA (Gemological Institute of America) to access its colour, cut, clarity and carat weight

CVD V'S HPHT

The main difference between CVD and HPHT diamonds is how they are created and their growth morphology inside their respective chambers. CVD diamonds are heated to around 800 degrees Celsius in a gas filled chamber and have only one growth direction which sees the carbon shaped into a cube. Meanwhile, HPHT diamonds are placed under immense pressure and even higher temperatures. It grows into a cuboctahedron shape with 14 different growth directions.

Each method for creating lab grown diamonds has its own advantages and disadvantages and what is “better” will differ between each person and their own needs and preferences. Both CVD diamonds and HPHT diamonds are high quality but overall CVD diamonds tend to have fewer impurities and can be more uniform in colour and clarity. The cost of producing CVD diamonds is also generally lower but this can vary depending on the quality and size of the diamond. Finally, CVD diamonds are more widely available than HPHT diamonds so are a more convenient option for many buyers of lab grown diamond jewellery.

Ultimately, the choice between CVD and HPHT diamonds will depend on your specific needs and preferences. If you prioritize high-quality, uniform diamonds, CVD might be a better option. Alternatively, if you are looking for a specific colour or are a larger diamond, HPHT might be the appropriate choice.

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Related Articles

What to Know Before Buying Lab Grown Diamonds

Why Should I Consider Lab Grown Diamonds Over Natural Diamonds?

The 4Cs

Jewellery Styles

Metals

Stone Shapes

Engagement Rings

Jewellery Categories

Elegance Engineered

Diamonds

Articles

Help & FAQs

Introduction

How Are High Pressure High Temperature Diamonds (HPHT) Created?

How Are Chemical Vapor Deposition Diamonds (CVD) Created?

CVD V'S HPHT

Related Articles

What to Know Before Buying Lab Grown Diamonds

Why Should I Consider Lab Grown Diamonds Over Natural Diamonds?

The 4Cs

Introduction

How Are High Pressure High Temperature Diamonds (HPHT) Created?

How Are Chemical Vapor Deposition Diamonds (CVD) Created?

CVD V'S HPHT