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Thursday, August 2, 2007

Hearts & Arrows Formation and Grading

In April 2004 Brian Gavin of presented his grading system for Hearts & Arrows optical symmetry at the First International Diamond Cut Conference in Moscow, Russia. It was hoped that laboratories and peers would unite to maintain higher standards for manufacture of diamond sold as "Hearts & Arrows." Though laboratories do not offer a grade for Hearts & Arrows, Whiteflash does, and safeguards buyers of the 'A Cut Above' brand with a guarantee of optical symmetry meeting the IDCC presentation criteria. - Here is Brian's presentation on the Formation of Hearts and Arrows

How the Hearts are Formed
Below are views of Hearts & Arows being forming during the cutting process as they would be seen through a regular Hearts & Arrows Viewer. The leftmost photos show the diamond blocked in 8. The center pair shows the pavilion fully cut, with crown still in 8. The pair on the right show the fully formed Hearts & Arrows when pavilion and crown have both been finished.


Russian Lab created Diamond is the BEST man-made diamond you can get! Each Hearts & Arrows stone is cut to the ideal proportions which must be met in order for a stone to display maximum sparkle and shine. The exact proportions of a Hearts and Arrows Ideal Cut stone are revealed when viewed through a star scope magnifier which shows an eight-point star pattern. This pattern is known as "hearts and arrows" in the diamond industry. Only stones cut to these perfect ideal proportions will reveal this pattern. And only with this cutting could a diamond be in its most brilliance!

These stones are formed under tremendous temperature (5000 degrees Fahrenheit) and possess optical characteristics almost the same as natural diamond. With a dispersive power greater than diamond (0.060 vs. 0.044), the overall effect is so similar it can even fool a trained gemologist.

Russian Lab diamonds are not cheap, they are retailing at US$200+ per carat and more for H&A Diamonds.


Russia is the world's second-largest diamond producer, but Soviet-era restrictions and the De Beers cartel have crimped Russian profits from the gems. Now South Africa-based De Beers is relaxing its grip on the world's diamonds, and Russia is angling to make a name for itself in the lucrative, secretive industry. "It's time for Russia to step out in this business," said Natalya Marakina, a member of the exclusive Russian Diamond Chamber, a club for diamond producers. "We are ready."

Russia has an advantage these days, as fears mushroom about gem sales financing the wars in Sierra Leone, Angola and Congo "The Russians are an important source of non-bloodied stones," said John Meyer, an industry analyst with Societe Generale in London. "The diamond industry in Russia has had a pretty low profile ... and this could be a pretty good marketing tool for them."

More exports would bring increased government revenues - the state owns a majority stake of Alrosa - and good news for an economy still hung over from a decade of decline. Most Russian diamonds come from Sakha, formerly known as Yakutia, a province five times the size of Texas that straddles the Arctic Circle. Soviet authorities coaxed workers to the ever-frozen wilderness with bloated salaries and generous benefits. Alrosa has trimmed the work force, but production costs remain high - about five times as much as De Beers spends extracting stones from its South African deposits. Once they leave Yakutia, diamonds are guarded by a series of private militias. Addresses of the Moscow vaults are a prized secret.

Russia produces about 20 percent of the world's rough diamonds and has vast untapped reserves. Russia's diamond monopoly Alrosa would develop new mines and reach more markets.

"After 40 years in the diamond business, Russia has grown out of children's shorts and understands how to sell diamonds so as not to harm the market or our own interests," said Valery Rudakov, chief of Russia's precious gem reserves.

Classification of natural diamond

Type Ia diamond: Contains nitrogen as an impurity in fairly substantial amounts (of the order of 0.1%), and which appears to have segregated into small aggregates. Also contains platelets, associated with the nitrogen impurity, the exact structure of which is not known. Most natural diamonds are of this type.

Type Ib diamond: Also contains nitrogen as an impurity but in dispersed substitutional form. Almost all synthetic diamonds are of this type.

Type IIa diamond: effectively free of nitrogen impurity. Very rare in nature, these diamonds have enhanced optical and thermal properties.

Type IIb diamond: A very pure type of diamond which has semiconducting properties: generally blue in colour. Extremely rare in nature.

Diamond Properties

Diamond distinguishes itself from other engineering materials by an impressive list of excellent properties:

Low friction
Low adhesion to other materials
High thermal conductivity
Low thermal expansion coefficient
Wide (optical) transmission band
High refractive index
Chemical inertness
Radiation hardness
Electric insulator
Good electronic properties

Natural Diamond

Diamond is the hardest known material. It has the highest thermal conductivity of any material at room temperature and several of its mechanical properties, such as bulk modulus and critical tensile stress for fracture, are also the highest known. It has an extremely low coefficient of friction, is an excellent electrical insulator (except for semiconducting Type IIb) and will not corrode.


One of the crystalline forms of carbon. It is historically known as a gemstone, however, it is the physically hardest substance known and is now widely used as an abrasive in high productivity tools in industry. Diamond also has other remarkable physical properties:

Density [g/cm3] : 3.52
Compressive strength [GPa] : 8.68
Fracture toughness [MPam1/2] : 3.40
Knoop hardness [GPa] : 57 - 104
Young's modulus [GPa] : 1141
Thermal expansion [10-6K-1] : 1.5 - 4.8
Thermal conductivity [Wm-1K-1] : 500 - 2000
Wear coefficient : 2.14 - 5.49