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Annealing

artificially enhance the colour of a diamond

Annealing diamond refers to a process in which diamonds are heated to high temperatures in a controlled environment to alter their internal structure or appearance. However, diamond annealing is quite different from annealing in other materials, like metals, because diamonds are already a highly stable, hard material. The process is typically used to modify certain properties of the diamond, such as colour or internal inclusions, rather than improving the material’s hardness or strength.

Here are the key aspects of diamond annealing:

1. Annealing to Alter Colour:
Annealing can be used to change or enhance the colour of a diamond. This is often done to lighten or darken the stone’s hue, or to bring out more desirable tones, like in fancy colour diamonds.

Heating Process: The diamond is subjected to high temperatures (sometimes exceeding 1000°C) in a controlled environment, typically in a vacuum or in an atmosphere of certain gases, such as nitrogen or hydrogen.
Effect on Colour: The heat causes changes in the diamond’s crystal structure, which can alter how light interacts with the stone, thus changing its colour. For instance, diamonds with brownish hues may turn to a lighter yellow or even white, while others might enhance their natural colour intensity.
2. Healing Inclusions (Internal Cracks or Imperfections):
Another purpose of annealing is to reduce the visibility of certain inclusions, particularly graining or small cracks. In this case, annealing can:

Relieve Stress: The heat from annealing can relieve internal stress in the diamond, causing cracks or inclusions to become less visible. This is especially useful for diamonds that have inclusions located near the surface, which can affect the diamond’s clarity.
Mend Cracks: Under controlled conditions, the annealing process can sometimes cause minor surface fractures to heal by encouraging the material around the crack to bond back together.
3. Limitations and Risks:
High Temperature: Because diamonds are made of carbon in a crystal lattice structure, they can be sensitive to extreme heat. The temperature and environment must be carefully controlled during the annealing process to prevent damaging the stone. If not done properly, excessive heat can cause the diamond to fracture or even shatter.
Not Suitable for All Diamonds: Annealing is not always suitable for all diamonds. For instance, diamonds with a high degree of internal stress or fractures may not respond well to heat treatment, as the process could cause further damage.
4. Impact on Diamond Value:
Colour Alteration: If annealing is used to improve the colour of a diamond, it can enhance the stone’s appearance and potentially increase its value, especially for diamonds with rare or sought-after colours.
Clarity Improvement: If annealing successfully reduces the visibility of inclusions, it can improve the diamond’s clarity, which could also make the diamond more valuable. However, some buyers may be cautious about diamonds that have undergone treatment, as they may prefer natural diamonds without any enhancements.
Disclosure: When diamonds are annealed or treated in any way, it’s important for sellers to disclose the treatment. Some buyers prefer untreated, natural diamonds, and the presence of treatment may affect the resale value or marketability.
5. Annealing in Industry:
While annealing is a term more commonly associated with metals or other materials, it is sometimes used in the diamond industry for specific treatments to improve the visual appeal or structural integrity of the diamond. The process is not typically used to improve hardness—since diamonds are already the hardest known material—but rather to address aesthetic and internal concerns.

Summary:
Annealing diamond involves heating the diamond to high temperatures in a controlled environment to alter its colour or reduce the visibility of internal inclusions.
It is often used to enhance the colour or improve the clarity of diamonds.
The process requires careful control to avoid damaging the diamond.
Annealed diamonds should be disclosed as treated, as they may affect the value, depending on the buyer’s preferences.

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If I buy a certified diamond, how do I know that the diamond in my ring is the one described on the diamond certificate or diamond grading report?

There are a number of ways to verify that your diamond matches the diamond certificate it is purchased with. If you purchased a diamond that is laser inscribed, ask your jeweller to show you the laser inscription under magnification. This way, you will always be able to identify the diamond as your own.

DCLA also performs a verification service, for both DCLA certified diamonds and for diamonds certified by other internationally recognised laboratories. Bring  or send your diamond, together with the diamond grading certificate, to the DCLA laboratory and the diamond will be conclusively matched against the certificate. DCLA can then cold laser inscribe the diamond with either the diamond grading certificate number, or with a personalised message.

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How do I know that my diamond certificate or diamond grading report is from an independent laboratory ?

Ask the jeweller if the diamond certificate comes from an independent diamond laboratory or if it produced by a diamond merchant or retailer, then do your research. Make sure the certificate is issued by the DCLA or another highly respected diamond grading laboratory; DCLA is the only diamond grading laboratory worldwide to offer a full-replacement Diamond Grading Guarantee.

Kimberley Diamonds closes its last mine

Controversial Australia-based miner Kimberley Diamonds has put its last remaining diamond mine into administration after it failed to secure fresh funding.

Controversial Australia-based miner Kimberley Diamonds has put its last remaining diamond mine into administration after it failed to secure fresh funding.

Kimberley, which avoided an estimated $40 million clean-up bill after it walked away from its Ellendale mine in Western Australia’s north, shut its Lerala operation in Botswana last week and placed the subsidiary responsible for the project into administration.

Kimberley said in a statement on its website that its subsidiary Lerala Diamond Mines had “no choice” but to place itself into administration after the parent company was unable to strike a new financing deal.

It had earlier stopped day to day operations at Lerala pending an overhaul of the mine’s diamond processing plant. “The successful completion of this performance improvement plant required further funds to be provided by investors and despite considerable progress being made on implementing these improvements, all of the required funds have not been forthcoming,” Kimberley said. “Kimberley has been in discussions with investors regarding further funds for some time, however to date no agreement for further and sufficient funding has been reached and KDL has been forced to cease providing financial support to Lerala.” But the collapse of Lerala won’t kill off the parent. Kimberley said it remained in discussions with investors for further funding and was “exploring corporate restructuring options”.

Kimberley delisted from the ASX earlier this year after a chequered history. The stock enjoyed a charmed run early on, surging from 11c in 2012 to $1.30 in 2013, but fell spectacularly in 2014 when it revealed it had failed to secure a price increase from global jeweller Tiffany & Co that it had already factored into its profit forecasts. Its shares never recovered, and last traded at just 0.7c prior to its delisting.

The company, chaired by former stockbroker Alexandre Alexander, also came under fire for its handling of the closure of Ellendale. The liquidators appointed to the Kimberley subsidiary that held Ellendale used a legal loophole to shift responsibility for the clean-up to the state government’s industry-funded mining rehabilitation fund.

The rehabilitation costs at Ellendale have been estimated at between $28m and $40m. WA’s new Mines and Petroleum Minister Bill Johnston has flagged an overhaul to prevent “rogue elements” taking advantage of the MRF.

Source: TheAustralian.com.au

De Beers taps into polished diamonds market with first-time auction

De Beers

Anglo American’s De Beers, the world’s largest rough diamond producer by value, has decided to begin selling its own polished diamonds in auctions for the first time in its history.

The pilot auction, scheduled for June, will include a wide range of polished stones manufactured directly from the company’s own rough diamonds.

“The pilot auction, scheduled for June 29, will include a wide range of polished stones manufactured directly from De Beer’s own rough diamonds.” All the polished rocks will carry grading reports from both the International Institute of Diamond Grading & Research (IIDGR) — De Beers’ in-house grading unit — and the Gemological Institute of America (GIA).

“We are interested in testing the level of demand from polished buyers for diamonds that have a clear and attractive source of origin, and that offer the assurance of product integrity that dual certification provides,” Neil Ventura, the miner’s executive vice president of auction sales, said in the statement.

If successful, the process would provide De Beers with more insight into the polished market, while also helping consumers fill gaps in supply or inventory if they were unable to find goods at the company’s rough auctions, he added.

All registered De Beers auction buyers will be eligible to bid in the first sale, which takes place on June 29.

Source: Mining.com

De Beers Profit Jumps as Diamond Market Stabilises

Underlying earnings jumped to $667 million in 2016 from $258 million a year earlier, parent company Anglo American said in a statement Tuesday. This came as revenue grew 30 percent to 6.07 billion, reflecting a 37-percent hike in rough-diamond sales to $5.6 billion.

Profit more than doubled for De Beers last year as trading conditions in the diamond-manufacturing sector improved and inventory levels stabilized.

Underlying earnings jumped to $667 million in 2016 from $258 million a year earlier, parent company Anglo American said in a statement Tuesday. This came as revenue grew 30 percent to 6.07 billion, reflecting a 37-percent hike in rough-diamond sales to $5.6 billion.

The midstream of the diamond industry returned to buying rough after a 2015 slump in demand that resulted from oversupply of polished and inflated rough prices. Manufacturers started working down their polished inventories in the second half of that year before restocking their rough supplies in 2016.

De Beers also lowered prices, with its rough-price index declining 13 percent across 2016. The miner consequently reduced its rough stockpiles during the year, management said. De Beers production fell 5 percent to 27.3 million carats, while sales volume leapt 50 percent to 30 million carats, meaning it sold a larger volume of stones than it mined. “2016 generally was a much better year for the diamond industry,” said Bruce Cleaver, De Beers chief executive officer. “The midstream performed much better than 2015, largely as a result of the strong and decisive action we took in 2015 to reduce production in accordance with demand.

The fruits of that tough action we took in 2015 was seen through 2016.” The company projected production would rise to 31 to 33 million carats in 2017, “because we see the market has recovered from where it was at the end of 2015,” noted Cleaver. The company maintained a conservative outlook for the diamond jewelry market given prevailing global macro-economic conditions and geopolitical risk.

Performance will be dependent on a number of macro issues, including the attitude of the new U.S. administration, the strength of the dollar, continued recovery in China and the impact of Indian demonetization, Cleaver explained. “All other things being equal, we think diamond demand will continue to grow along with GDP growth,” he said. Source: diamonds.net

Lucara Sells Its 813 Carat Diamond for US$63 Million

Lucara Sells Its 813 Carat Diamond for US$63 Million, the Highest Price Ever Achieved for the Sale of a Rough Diamond.
Lucara Sells Its 813 Carat Diamond for US$63 Million, the Highest Price Ever Achieved for the Sale of a Rough Diamond.

Lucara Sells Its 813 Carat Diamond for US$63 Million, the Highest Price Ever Achieved for the Sale of a Rough Diamond.

Lucara, is pleased to announce that the exceptional 812.77 carat, Type IIa diamond recovered from the Karowe mine in Botswana in November 2015, has been sold for US$63,111,111 (US$77,649 per carat).

As part of the sale, Lucara has partnered with Nemesis International DMCC, and retains a 10% interest in the net profit received from the sale of the resultant polished diamonds.

The 813 carat diamond has been named, “The Constellation”, in collaboration with our partner. Lucara is a well-positioned diamond producer.

The Company’s main producing asset is the 100% owned Karowe Mine in Botswana.

De Beers cuts rough diamond prices and sight

De Beers which produces thirty percent of world rough diamonds has cut prices by 10 percent for the sight.

This comes after two reductions in its annual production output by 15 percent failed to slow slump in prices of rough.

Rough diamond prices have dropped 14 percent in some categories and are in their fifth consecutive quarterly loss, which is the longest in a decade.

De Beers cut the size of the sight to $250 million and reduced the prices by 9 percent, according to sight holders.  

De Beers has also contributed tens of millions to a jewellery advertising campaign. Its advertising campaign will promote diamond jewellery in the U.S. and to Chinese consumers.

DCLA Diamond jewellery valuation with Cold Laser Inscription

DCLA Australia’s leading diamond laboratory valuation service now available.

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The DCLA valuation will guarantee the diamond replaced with the prefect like for like stone.

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Call DCLA for information or to book you appointment.