Synthetic Diamonds

Synthetic diamonds are a hot subject at present and there is more production of gem quality synthetic diamonds now than ever before. The main companies involved are Gemesis Cultured Diamonds and Apollo Diamond Inc, both companies are based in America. There have been major advances in the production of synthetic diamonds since General Electric first produced synthetic diamonds in 1954.

• Synthetic diamonds are man-made diamonds which 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 method are normally not colourless with the majority being shades of yellow.
• Chemical Vapour Deposition (CVD) is a more recent method of production. This method does produce colourless synthetic diamonds and growth rates are now a matter of hours.
• Identification of synthetic diamonds requires highly equipped gemological laboratories and highly trained personnel.
• De Beers developed the DiamondSure and DiamondView technology to enable identification of synthetic diamonds.
• All diamonds listed on the diamonds.co.nz database have been tested using the DiamondSure to ensure 100% natural origin.

Diamonds treated with HPHT show greenish-yellow
fluorescence, green more intense around growth
lines. Pictured under dark light showing illumination.

High Pressure High Temperature Treatment (HPHT)

HPHT treatment 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 earths 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 the HPHT treatment be successful. It is estimated that only three diamonds out of ten thousand diamonds have this combination to be suitable for treatment.

• Only a very small percentage of natural origin diamonds can be treated using HPHT. As stated it is approximately three diamonds out of ten thousand.
• HPHT diamonds can be identified for further testing, using the DiamondSure.
• Bellataire Diamonds are the most widely known brand of HPHT diamonds.
• Full disclosure, including laser inscription on the girdle is essential.
• diamonds.co.nz will not be associated with HPHT diamonds.

Fracture Filling

Fracture filling is a post - cutting process which improves the clarity of a diamond. This is achieved by 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” showing 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

Laser drilling is another treatment designed to improve the clarity and therefore appearance of a diamond which 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 by acid. Some diamonds can 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 laser drilled diamonds.

Colour Enhancement

Diamonds that have been treated to produce fancy colours are called treated colour or colour enhanced diamonds. The process involves artificially altering the colour of a diamond by exposure to radiation and/or other methods. Colours produced are the full range of the spectrum.

• Colour treated diamonds are considerably less expensive than natural fancy colours.
• Colour treated diamonds should definitely be disclosed to the consumer at the time of sale.
• diamonds.co.nz is only involved with natural fancy colour diamonds. We do not stock treated colour diamonds.