High Pressure High Temperature Treatment

Continuous developments in technology have created different treatment techniques used to improve the appearance of diamonds.  The colour of particular types of diamond can be altered artificially by subjecting them to conditions of extreme heat and pressure. The colour of a diamond following HPHT- treatment is dependent on the exact conditions used and the diamond type.

Scientists divide diamonds into various types. The vast majority (over 97%) of diamonds handled by the jewellery industry are called Type I. A tiny minority of diamonds (approx. 2%) are called Type II.

Type II diamonds and a sub-group of Type I diamonds which show a trace of brown colour can be permanently de-colourised by subjecting them to a sophisticated process using extremely high pressures and high temperatures (HPHT).  A diamond of the more common colour grades, ‘J’ to ‘M’, can be HPHT-treated to the more desirable, rarer grades, ‘D’ to ‘H’. This process is perfectly acceptable so long as it is disclosed to the purchaser.

HPHT- treated diamonds are impossible for gemmologists to identify using standard gem testing instruments and therefore, undisclosed HPHT- treated diamonds are a great concern to the gem and jewellery industry. However, AnchorCert has invested in the latestest technology which can help identifiy HPHT-treated diamonds. All diamonds submitted to any AnchorCert Office are screened and examined to ensure they are natural and have not been subjected to any forms of treatment (including HPHT). We are the only UK diamond grading authority equipped to identify HPHT treatment.

CVD - Chemical Vapour Deposition

Technology is advancing all the time with techniques and processes creating new developments.

Chemical vapour deposition, developed in the mid 1980’s is a process by which incredibly thin films of diamond a few microns thick can be generated and deposited on a base.  The process involves high temperatures (over 2000°C) and lower pressures than involved in HPHT. Mixtures of hydrogen and hydrocarbon gases are energised with heat or electrical energy in a deposition reactor. The carbon molecules are deposited on a substrate as a thin film of polycrystalline material.  Quality and purity are very high and particular diamond properties can be selected.  Boron added to the growth gases, for example, will produce electrically conducting diamond.  When the diamond layer has reached the correct thickness the reactor is shut down and the CVD wafers can be removed. Single crystal diamonds can also be grown, but sizeable gem quality is proving difficult. 

CONFLICT DIAMONDS - THE FACTS

Environmental and Humanitarian Issues are of increasing concern to the consumer.  Many are now seeking reassurance that the goods they are buying have been produced in a responsible manner and that the people involved in the supply chain have not suffered in any way.

This is of particular concern to many when buying high value luxury items as an expression of love and commitment.

It is true that in the past “conflict diamonds” have been a source of revenue which has funded civil conflict in countries such as Sierra Leone and Angola. This problem was recognised in 1998, following a decade of violent conflict in the continent of Africa. Concern from non government organisations such as Global Witness and the jewellery trade itself resulted in a United Nations resolution in 2000 and the establishment of the Kimberley Process in 2002.  The Kimberley Process has been adopted by 68 governments worldwide and regulates all rough diamonds. It is now estimated that only 1% of the annual production of diamonds are traded outside the Kimberley Process. All responsible UK retailers will require that diamonds have a Kimberley certificate to ensure that they are not conflict

For more details visit www.kimberleyprocess.com

The mining of diamonds and gold employs millions of people in the world’s poorest areas, particularly in Africa, and in India a further 700,000 are employed in the diamond cutting industry. It is crucial to the survival of these people who in most cases have no alternative source of employment or income.

The Western consumer spend on gold and diamonds is keeping millions alive. If this spend should fall for whatever reason it would have severe consequences for many communities and cause untold suffering for the people of Africa and their families This particularly applies to those in areas where long term conflict has devastated the economy and the population are struggling to recover and survive..

The facts are:

• The Diamond  industry alone employs 10 million people globally
• As two of its major resources diamonds & gold are helping transform Africa & the lives of its people
• Income from diamonds and gold make a difference in the developing world by providing jobs, roads, healthcare, education
• The Kimberley Process has significantly reduced the amount of conflict diamonds in circulation
• Major players at every stage of gold an diamond supply chain have committed to taking a more responsible approach

For more information visit www.diamondfacts.org or www.responsiblejewellery.com