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Gem Quality

Only about 20% of mined diamonds are of gem quality, meaning they meet the necessary standards for use in jewellery. The remaining 80% fall into the industrial-grade category, used in various commercial and technological applications. Let’s explore this in more detail:

Breakdown of Diamond Quality
Gem-Quality Diamonds (≈20%)

These diamonds are characterised by high clarity, colour, and cut quality, making them desirable for jewellery.
They undergo cutting and polishing to enhance their brilliance before being set in rings, necklaces, earrings, and other fine jewellery.
Their value depends on the 4 Cs (Carat, Cut, Colour, Clarity) and whether they are natural or treated.
Industrial-Grade Diamonds (≈80%)

These diamonds are lower in clarity, may have visible inclusions, and often exhibit yellow, brown, or grey colours that make them unsuitable for jewellery.
They are used in industries due to their hardness and durability, which are essential for cutting, drilling, grinding, and polishing applications.
Common uses include:
Diamond-tipped drill bits and saw blades for construction and mining.
Abrasive powders for polishing and grinding metals.
High-tech applications, such as semiconductors and heat conductors in electronics.
Why the Low Percentage of Gem-Quality Diamonds?
Several factors contribute to why only a small fraction of mined diamonds qualify as gem-grade:

Formation Conditions: Natural diamonds form under extreme pressure and temperature deep within the Earth’s mantle. Impurities or irregular growth can affect their clarity, colour, or shape.
Inclusions and Blemishes: Many diamonds contain internal inclusions (tiny fractures or foreign minerals) and external blemishes, making them less suitable for jewellery.
Colour and Transparency: Gem-quality diamonds are typically colourless to light yellow (D-Z on the GIA colour scale). Many mined diamonds have a strong brown or grey tint, reducing their desirability.
Cutting Yield: Some rough diamonds, even if of good quality, may be inefficiently shaped for cutting into marketable gemstones.
Impact on the Diamond Market
Rarity Drives Value: Since high-quality diamonds are less common, they retain their value better than industrial-grade diamonds.
Lab-Grown Diamonds: The gap in supply between industrial and gem-quality diamonds has led to advancements in lab-grown diamonds, which can be produced with high clarity and controlled quality.
Recycling & Recutting: Some lower-quality diamonds can be recut or treated (e.g., laser drilling, fracture filling) to enhance their appearance, but these diamonds are usually less valuable than untreated stones.

The fact that only 1 in 5 mined diamonds meets gem-quality standards highlights the rarity and value of fine diamonds. This also influences pricing, sourcing strategies, and market trends, as both natural and lab-grown diamonds compete in the luxury and industrial sectors.

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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.

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

DTC 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

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.

Blue Moon Diamond

The Blue Moon Diamond has been sold for a record US$48.26m at Sotheby’s in Geneva.

The sale price is a record per carat and for total value for any gemstone.

Blue Moon Diamond has no inclusions and has been officially declared flawless.

The 29.62-carat diamond was found at the Cullinan Mine in South Africa in January last year, blue diamonds make up only 0.1% of diamonds unearthed at the mine.

It was then cut and polished in New York, a process which took six months and eventually produced the 12.03 carat vivid blue gem.

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.

De Beers sightholders refuse boxes Update

De Beers’s sightholders.

De Beers’s the world’s largest rough producer felt the pain, when only $300 million of the $450 million estimated sight was taken up by their sightholders. This leaves 30 percent of the rough on offer  on the table.

Anglo has previously counted on diamond revenues to offset a collapse in the price of other metals and minerals it mines. Anglo may cut the company’s dividend for the first time since 2009 according to analysts.

This is an indication of turmoil in the $80 billion diamond industry as traders, cutters and polishers suffer from a poor liquidity and weaker demand for jewellery.

Producers in India, where 90 percent of rough diamonds are cut and polished, may halt imports over the supply glut.

Update: Report sightholders may have refused 35%-50% at July sight which may be as low as $200M.

De Beers diamond grading and inscription facility opened in Surat

The major investment in Surat facility reflects a world class diamond cutting and polishing centre characterised by skill, innovation and the effective use of technology.

De Beers the world’s leading diamond company is considering a diamond auction centre in India.

This laboratory is the second of its kind in the world owned International Institute of Diamond Grading and Research. 

The laboratories primary function will be to select and inscribe Forevermark diamonds with the unique serial number to deliver an accurate and reliable grading for diamonds.

De Beers is the world’s leading diamond company established in 1888  experts in exploration, mining and marketing of diamonds.