How are lab-grown diamonds made?

CVD and HPHT – Production of Lab Grown Diamonds
ROSY DIAMOND KNOWLEDGE

How are Lab Grown Diamonds created?

A Lab Grown Diamond is not cast or simply artificially shaped. It is created through controlled crystal growth.

From the tiny Diamond seed through CVD or HPHT to the cut jewelry Diamond, it goes through several precise work steps.

THE PROCESS

From the Diamond seed to the finished Diamond

Production begins with a very small Diamond seed. Under controlled conditions, additional carbon atoms attach to the existing Diamond structure, and the crystal grows.

1

Diamond seed

A small Diamond structure forms the basis for further crystal growth.

2

Growth

The crystal grows using a controlled CVD or HPHT process.

3

Processing

The resulting rough crystal is planned, cut, polished, and then evaluated.

ImportantLaboratory production means genuine crystal growth. It does not merely replicate the external shape of a Diamond.
Diamond seed as the starting point for the growth of a Lab Grown Diamond
STEP 1

The Diamond seed

It begins with a small Diamond structure, often referred to as a Diamond seed or seed.

This seed already provides the ordered crystal structure onto which additional carbon atoms can attach during growth.

The goal is not to create a material that merely looks like a Diamond. It is meant to become a growing Diamond crystal.

A helpful imageThe Diamond seed is the starting point from which the crystal continues to grow under controlled conditions.
STEP 2 · CVD

How does the CVD method work?

CVD stands for Chemical Vapor Deposition.

A Diamond seed is placed in a controlled reaction chamber. There, carbon-containing gases create an activated environment in which carbon can be deposited on the Diamond surface.

This is how the Diamond continues to grow layer by layer.

  • Diamond seed as the basis for growth
  • controlled gas atmosphere
  • activated plasma environment
  • step-by-step crystal growth
CVD growth process of a Lab Grown Diamond
HPHT growth process of a Lab Grown Diamond
STEP 2 · HPHT

How does the HPHT method work?

HPHT stands for High Pressure High Temperature.

This method creates a technical environment with very high pressure and high temperature.

Under these conditions, carbon can crystallize on a Diamond seed, forming a larger Diamond crystal.

  • very high pressure
  • high temperature
  • controlled growth environment
  • Crystal growth on a Diamond seed
CVD OR HPHT?

Which method is better?

CVD and HPHT are two different methods for producing Lab Grown Diamonds. The designation of the growth method alone does not indicate which finished Diamond is more beautiful or of higher quality.

CVD describes how it is created

The subsequent quality also depends on the individual properties and processing of the specific Diamond.

HPHT describes how it is created

Here too, the cut, color, clarity, dimensions, and carat weight of the finished Diamond should be considered.

ROSY TipDo not choose a Diamond based solely on the term CVD or HPHT. The quality of the finished stone is what matters.
AFTER GROWTH

What does Post-Growth Treatment mean?

Growth and post-growth treatment are two different steps.

For certain Lab Grown Diamonds, additional technical processes may be used after the actual crystal growth, for example, to change or optimize specific color properties.

Transparency mattersAn independent gemological report can contain information about the growth method and any recognizable or documented post-growth treatments.
STEP 3

From rough crystal to jewelry Diamond

From rough crystal through cutting to polished Lab Grown Diamond

After growth, there is not yet a finished jewelry Diamond. The rough crystal must first be analyzed and planned for the best possible cut.

1

Planning

The crystal's shape, proportions, and potential yield are assessed.

2

Cutting

The rough crystal receives its planned shape and facet structure.

3

Polishing

The facets are precisely worked to create the desired optical effect.

The same growth process can produce very different finished Diamonds—for example, Round Brilliant, Oval, Pear, Cushion, or other Fancy Shapes.

QUALITY CONTROL

What happens after cutting?

After processing, the finished Diamond is assessed based on its gemological properties.

4C

Carat, Cut, Color, and Clarity help describe important characteristics of the Diamond.

Additional characteristics

Depending on the shape and report, dimensions, polish, symmetry, and other properties may also be documented.

ROSY Certificate StandardFor an individual Lab Grown Diamond of 0.50 ct or more, ROSY Lab Diamonds provides an independent IGI grading report as well as the ROSY product certificate.
IN BRIEF

How a Lab Grown Diamond is created

  • A Diamond seed forms the starting point.
  • The Diamond grows through CVD or HPHT.
  • A rough crystal is created—not yet a finished gemstone.
  • Any post-growth treatments take place only after growth.
  • The rough crystal is planned, cut, and polished.
  • The finished Diamond is assessed gemologically.
  • Visible quality does not depend solely on the growth method.
ROSY DIAMOND KNOWLEDGE

Understand the technology. Assess quality more effectively.

Deepen your knowledge of CVD, HPHT, the 4Cs, certificates, and the properties of modern Lab Grown Diamonds.

Discover Diamond Knowledge What is a Lab Grown Diamond? Myths & Facts