Treatments & Lab-Grown Diamonds

Lab-Grown Diamonds

Synthetic or lab-grown diamonds (we prefer to call them factory grown) are a hot topic currently, and more gem-quality synthetic diamonds are now being produced than ever before.

The main companies involved in the production of lab-grown diamonds are Element Six, a De Beers subsidiary, Pure Grown Diamonds, and Diamond Foundry, among many others.

There have been major advances in the production of synthetic diamonds since General Electric first produced synthetic diamonds in 1954.

  • Lab-grown diamonds are synthetic diamonds that have the same chemical, physical and optical properties as natural diamonds.
  • They are produced by subjecting carbon-bearing material such as graphite to high temperature and pressure. Diamonds produced by this HPHT method are normally not colourless, with the majority being shades of yellow.
  • Chemical Vapour Deposition (CVD) is a more recent method of production that does produce colourless synthetic diamonds, and growth rates are now a matter of weeks. In chemical vapour deposition, a thin "seed" diamond is placed inside a sealed chamber and subjected to high temperatures, generally around 800 degrees Celcius. A carbon-rich gas mixture — usually consisting of hydrogen and methane — is then introduced into the chamber.
  • Identification of synthetic diamonds requires gemological laboratories with very specialised equipment and highly trained personnel.
  • De Beers developed the DiamondSure™ and DiamondView technology to enable the identification of synthetic diamonds.
  • All diamonds listed on diamonds.co.nz have been tested using DiamondSure™ technology to ensure 100% natural origin. 
  • diamonds.co.nz has made the decision not to sell synthetic lab-grown diamonds.
  • If you are concerned about ethical diamonds as well as the sustainability of your purchase, did you know that the greenhouse gas footprint per 1ct of natural polished diamond is 160kg CO2e (carbon dioxide equivalent), which is 69% less than the estimated 510kg CO2e footprint of a lab-grown synthetic diamond? 
  • If you would like to find out more about lab-grown diamonds at the most competitive prices, you can visit lightboxjewelry.com 

High-Pressure High-Temperature Treatment (HPHT)

Treated DiamondsHigh-Pressure High-Temperature treatment (HPHT) was developed by General Electric to improve the colour of certain types of natural diamonds.

During the formation and subsequent transportation of diamond crystals from deep within the earth's crust to the surface, distortion of the crystal lattice causes some diamonds to have a brown body colour.

Only if the diamond has negligible nitrogen and boron can HPHT be successful. It is estimated that only 3 out of 10,000 diamonds have this combination and are thus suitable for treatment.

  • Only a very small percentage of natural-origin diamonds can be treated using HPHT — approximately 3 out of 10,000.
  • HPHT diamonds can be identified for further testing using DiamondSure™ technology.
  • Bellataire Diamonds are the most well-known brand of HPHT diamonds.
  • Full disclosure, including laser inscription on the girdle, is essential.
  • diamonds.co.nz only sells Black HPHT Diamonds.

Fracture Filling 

Flash Effect Fracture filling is a post-cutting process that improves the clarity of a diamond, and is achieved through a process of filling surface-reaching cleavages, fractures and laser drill holes with glass or epoxy to make them less visible.

  • Fracture filling can be identified relatively easily under magnification by trained personnel. The main identifying characteristic is the "flash effect", which shows colour in the filled fracture.
  • Fillings can be damaged by high temperatures and acids, returning the diamond to its original clarity grade.
  • GIA's Gem Trade Laboratory — and other leading laboratories — will not grade fracture-filled diamonds.
  • Fracture filling should definitely be disclosed to the consumer at the time of sale.
  • diamonds.co.nz will not have any association with fracture-filled diamonds.

Laser Drilling

Diamond Laser Drilling Laser drilling is another treatment that is designed to improve the clarity (and therefore appearance) of a diamond that contains dark inclusions.

A tiny hole is drilled into the diamond with a laser until it reaches the inclusion. The inclusion is then bleached or dissolved using acid. Some diamonds may have multiple drill holes.

  • Most laser drill holes are very difficult to find without the aid of magnification, especially if the inclusion is close to the surface.
  • Laser drill holes can be filled with glass or epoxy.
  • Laser drilling should be disclosed to the consumer at the time of sale.
  • diamonds.co.nz will not purchase or sell laser-drilled diamonds.

Colour Enhancement

Colour Treated Diamonds Diamonds that have been treated to produce fancy colours are called colour-treated or colour-enhanced diamonds.

The process to produce colour-enhanced diamonds involves artificially altering the colour of a diamond by exposing it to radiation and/or other methods. The colours produced are the full range of the spectrum.

  • Colour-treated diamonds are considerably less expensive than natural fancy coloured diamonds.
  • Colour-treated diamonds should definitely be disclosed to the consumer at the time of sale.
  • diamonds.co.nz is only involved with natural fancy coloured diamonds — we do not sell colour-treated diamonds. We will supply treated black diamonds upon special request.