Sunday, October 5, 2014

Carats

The weight of a diamond is measured in metric carats, abbreviated as ct(s) and is divided into 100 points. One carat equals 0.200 grams. The term carat originated from the carob seed, an early Arabian trading measure, which is why some people refer to a 1.00 ct. stone as a 4 grainer.

Carats

Large diamonds are rarer and more valuable than smaller stones. However, the difference is more than numerical. One 1.00 carat diamond has the same carat weight as five 0.20 carat stones. Because the larger diamond is so much rarer, it will be worth many times more than the sum of the value of the five smaller diamonds.

Colourless and coloured diamonds are measured the same. However since coloured diamonds are more rare they demand a higher price per carat than a colourless diamond. The colour of a coloured diamond is more important than weight as a small red which is exceptionally rare will be more valuable than a large yellow.

Certificates and how to read them

How to read a certificate

The GIA Coloured Diamond Grading Report contains the following information:

Date: The date that the diamond was examined by the GIA and the report was issued.
GIA Report Number: The unique tracking number assigned to each diamond and report. Sometimes this number is laser inscribed on the girdle of the diamond. If so, this will be mentioned in the comment section of the report.
Shape and Cutting Style: (e.g. Round Brilliant, Cut-Cornered Rectangular Modified Brilliant, etc.)
Measurements: The length, width and depth of a diamond, expressed in millimetres to the nearest one hundredth of a millimetre.
Carat weight: The weight of a diamond is measured in metric carats, abbreviated as ct(s) and is divided into 100 points.
Colour Origin: States if the colour of the diamond is natural or a result of a treatment. If the colour is enhanced or otherwise artificially treated, the treatment will be disclosed under the comment section at the bottom of the certificate.
Colour Grade: Describes the combined effect of tone and saturation in color and is expressed in terms like Faint, Light, Very Light, Fancy, Fancy Light, etc.
Distribution: Describes the evenness of the color.
Clarity Grade: Clarity is a gemstone’s relative freedom from clarity characteristics, which are known as blemishes and inclusions.
Finish: A diamond’s final detailing, its finish is made up of two qualities: polish and symmetry.
Polish Grade: The overall condition of the facet surfaces of a finished diamond.
Symmetry: The precision and balance of a finished gem’s cut. This includes the exactness of the proportions and the balanced placement of the diamond’s facets from one side to another.
Fluorescence: The emission of visible light by a material when it is exposed to ultraviolet radiation (like a ‘black light’ for example).
Comments: Additional clarity characteristics that are too minor to be reflected in the plot are mentioned in this section. Between the comments section and the plot, all inclusions, visible under a 10X magnification are accounted for. Furthermore, if the girdle is ‘painted’, ‘digged out’ , bearded, polished/ faceted or laser inscribed, this will be mentioned in the comments section as well.

REFERENCE DIAGRAMS

The reference diagrams include the Plot and the Proportion Diagram. The Key to Symbols is located below the plotting diagrams and lists the characteristics and symbols shown on the plotting diagrams.

Diamond Plot: A plot is a graphic map of the clarity characteristics -visible under 10X magnification- of a diamond and is used to document the condition of the stone, support and explain the clarity grade and to identify the stone.

At the right of the plotting diagram is the proportion diagram located. This is a representation of the diamond’s proportions.

Diamond Proportions: A diamonds’ proportions are the angles and relative measurements and the relationship between them. The proportions are graphically represented in the proportions diagram.
Table Percentage: The table percentage of a diamond is calculated by expressing the average table diameter as a percentage of the average girdle (the outline) diameter.
Total Depth Percentage: The total depth percentage of a round brilliant is its table-to-culet depth, expressed as a percentage of its average girdle diameter.
Girdle Thickness: The function of the girdle is to prevent damage and providing an edge for setting the stone into jewellery.

Culet Size: The culet is the small facet at the bottom of a finished gemstone. In the sample above, the culet is None. This is almost always the assessment.

SCALE REFERENCES

GIA Clarity Scale: this scale displays the GIA Clarity grades and their relative positions in the GIA Diamond Grading System.
GIA Coloured Diamond Scale: This scale shows the general interrelation of GIA fancy-grade terms, that are used to describe the combined effect of tone and saturation, in colour space.

SECURITY

Bar Code: The bar code is displayed horizontally on the right-hand side of the report and is used for internal purposes to track the diamond and its progress through the GIA Laboratory during report preparation. This number is different from the GIA Report Number.
Disclaimer: Beneath the bar code is the GIA disclaimer.
Security Features: The disclaimer is followed by the GIA hologram. This is one of the numerous security features that ensures that the report is authentic. Other security measurements include micro-print lines, chemical sensitivity and a security screen.

Certification is often regarded as the “5th C” in addition to Cut, Clarity, Colour and Carat. It provides proof of the value of the diamond to potential investors. The three most reputable gemmological laboratories that issue certificates are the GIA, IGI and HRD. Generally, the GIA-certificate is by far the most preferred in the market, since the GIA has developed many of the scales that are now globally used as the industry standard to grade, appraise and value diamonds.

Founded in 1931, the Gemological Institute of America (GIA) is a non-profit institute dedicated to research and education in the field of gemmology. The GIA is owned by the Mouawad family and has the mission to protect all buyers and sellers of gemstones and maintaining the standards in the industry. The GIA acts as a resource and point of reference in the trade.

The International Gemological Institute (IGI) is a diamond, coloured stone and jewellery certification organisation, established in 1975 with its headquarters in Antwerp. The IGI is the largest independent gemmological laboratory worldwide.

The Hoge Raad voor Diamant (HRD) or High Diamond Council in English was founded in 1973 in Antwerp, Belgium by the Belgian government and diamond industry representatives. The HRD Antwerp is the subsidiary of the Antwerp World Diamond Centre (AWDC) and is one of Europe’s oldest laboratories.

Each Argyle pink diamond of 0.15 carat or above is laser inscribed with a serial number. The Argyle Pink is accompanied by a certificate also guaranteeing its origin and offering an assurance that you are purchasing something truly rare. The diamond will usually have a GIA certificate in addition to the Argyle certificate.

Verify the authenticity of your diamond certificate by clicking the logo's.

"A little knowledge is dangerous."

- Henri Barguirdjian, President and CEO of Graff Diamonds USA

Kimberley Process Certificate (KPC)

Diffraction Diamonds only sources diamonds that are part of the Kimberley Process, in compliance with the United Nations resolutions and are therefore ‘conflict free’.

Conflict diamonds (also known as blood diamonds), are rough diamonds used by rebel movements to finance war against legitimate governments. The trade in illicit stones has fuelled devastating conflicts in countries such as Angola and Sierra Leone.

The Kimberley Process is a joint governments, industry and civil society initiative to stem the flow of rough conflict diamonds. In December 2000, the United Nations General Assembly adopted a landmark resolution supporting the creation of an international certification scheme for rough diamonds. The Kimberley Process Certification Scheme (KPCS) entered into force in 2003 and was designed to provide a means of certifying diamonds as ‘conflict free’. It imposes extensive requirements on its members to enable them to certify them as such.

The Kimberley Process has not just stemmed the flow of conflict diamonds, it has also help stabilise fragile countries and increase the revenues of poor governments by bringing large volumes of diamonds onto the legal market.

The scheme provides assurance to consumers purchasing diamonds that they are not financing war and human rights abuses.

Since the implementation of the Kimberley Process, conflict diamonds have been reduced to less than 1% of the trade. Today, the diamond revenue is instrumental in the development of African countries, contributing to education, health care, financial and economic sectors of African countries.

Learn more about conflict diamonds and the Kimberley Process in our Diffraction Article.

“The diamond industry is vital to the southern African economy”

- Nelson Mandela, 17th November 1999

Thursday, October 2, 2014

diamond that could be worth more than £60million.

'Exceptional' 122-carat diamond that could fetch £60m: But will it bring you bad luck?

It was found by Petra Diamonds Ltd at its Cullinan mine in South Africa
Comes months after it sold 29.6-carat blue diamond from mine for £14m
It is expected to eclipse world's most expensive, a 507-carat white diamond

By MATTHEW BLAKE

PUBLISHED: 09:55, 13 June 2014 | UPDATED: 01:45, 14 June 2014

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It is the size of a strawberry and weighs a bit less than three pound coins.

But if you had this rare blue beauty in your pocket you would be carrying around a diamond that could be worth more than £60million.

The ‘exceptional’ 122.5-carat blue diamond was unearthed at the Cullinan mine in South Africa which is renowned for producing giant gems.

Rare gem: Petra Diamonds Ltd said it had recovered the 'exceptional' 122.52-carat gem (pictured from two angles) at its Cullinan mine in South Africa

Sparkler: The jewel, about the size of a strawberry (pictured), is so pure that it is expected to eclipse the current world's most expensive diamond - a 507-carat white diamond dug from the same mine that sold for £20 million in 2010

A blue stone from the mine fetched £508,000 per carat earlier this year. If this much larger one achieves a similar valuation, it would command a price tag of £62million – smashing the record price paid for a rough stone.

Anyone who buys it, however, will be hoping for better luck than the owners of the famous deep blue Hope Diamond. It supposedly puts a curse on those who possess it, as the guillotined Louis XVI and his wife Marie Antoinette discovered.

The newly discovered diamond was dug up by Jersey-based Petra Diamonds at its mine near Pretoria. One industry insider said it was almost unheard of to find a blue stone weighing more than 100 carats.

Diamond mine: Other notable diamonds discovered at the Cullinan mine (pictured) are the 25.5 carat Cullinan blue diamond found in 2013 and sold for £10 million ($16.9 million), and the Star of Josephine diamond found in 2008 and sold for £5.59 million ($9.49 million)

Rough diamond: It comes months after Petra sold a 29.6 carat blue diamond (pictured) from the same mine for more than $25 million

Rough to royalty: A miner holds the Cullinan Diamond shortly after it was found in 1907 (left) before it was cut in two and used for the British Crown and Sceptre (pictured on the head of Queen Elizabeth II in 2009)

A carat is equal to one-fifth of a gram, so Petra’s 122.5-carat stone is about 25g. In comparison, the average centrepiece diamond on an engagement ring weighs about one carat and is usually white.

Shares in Petra rose nearly 8 per cent on the find yesterday, adding some £66million to the value of the company in a day.

THE CURSE OF THE BLUE GEM

The 45-carat blue Hope Diamond, which is said to put a curse on its owner, is worth more than £200million.

It is thought to have been stolen in 1653 in India from a statue of Hindu goddess Sita by Jean Baptiste Tavernier, who was reported to have been killed by rabid dogs at the age of 84.

The diamond is also known as Le Bijou du Roi, or The King’s Jewel, and was owned by Louis XVI and Marie Antoinette who were guillotined in 1793 by the French revolutionaries.

It is then thought to have been smuggled to London. Lord Francis Hope, after whose family it is named, had to sell it in 1894 after going bankrupt.

Another supposed victim, Prince Ivan Kanitovski, was killed by Russian revolutionaries. Today it is in the Smithsonian natural history museum in Washington.

The current record price for a rough stone was set by Petra’s sale of the 507-carat Cullinan Heritage, a white diamond, in 2010 for nearly £21million.

Blue diamonds get their colour from small amounts of the chemical element boron trapped in their crystal structure. The more ‘blue’ it is, the greater the value. They are the rarest diamonds after red, which are almost never found.

Petra’s blue diamond is being kept under guard at a secret location in South Africa and will be sold in a private tender process in Johannesburg before being cut and polished.

The Cullinan mine is recognised as the most important diamond mine in the world. It is famous for producing the world’s largest white diamond, the 3,106-carat Cullinan Diamond, which was found in 1905.

The door-stopping diamond was originally discarded by a hasty mine manager who thought it was too big to be anything other than a crystal. It was recovered and presented to King Edward VII in 1907, and gems cut from it are centrepieces of the Crown Jewels at the Tower of London.

Petra Diamonds believe the mine has another 50 years left in it.