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BUYING & SELLING TIPS
How to buy a diamond
When buying a diamond, size is not all that matters. There are the traditional 4 C's - cut, color, carat and clarity - and now a 5th C, Country of Origin. Here, international jewellery and watch writer Carol Besler presents the 5 C's.
Cut and shape
Cut is often confused with shape. Shape refers to the overall outline of a diamond when viewed from the top. Emerald, marquise, oval, pear, heart and cushion are all diamond shapes. They are usually referred to in the trade as “fancy” shapes.
The overwhelming majority of diamonds, however, are round, and there are several “cut” options. The most common cut is the round brilliant, which has 56 facets, including 33 on the crown or upper part of the stone, and 25 on the pavilion, or lower part of the stone. The placement and proportion of these facets affects how light travels through a diamond and where it exits a diamond. The goal is to angle the facets in a way that causes them to reflect light out through the top, or table, of a diamond. When a diamond is too shallow, light will exit through the bottom or pavilion. When a diamond is too deep, light will exit through the sides of the pavilion.
Many gemological laboratories include a cut grade in their reports, which refers to the placement and proportions of facets in a round-brilliant diamond, measuring the extent to which they maximize brilliance (light return), scintillation (sparkle) and fire (flashes of color). There is no universal agreement on a single set of angles and proportions that constitute an “ideal” cut, but there are general parameters that dictate the quality of a diamond’s cut, and an appraiser will consider the combination of angles and the resulting light return in a cut grade.
Polish and symmetry also affect the beauty of a diamond. Polish refers to the smoothness of the diamond’s facets. Symmetry refers to the alignment of the facets. Even with a good cut, poor symmetry can redirect light return, causing it to exit through the pavilion instead of the table. And a poor polish can make a diamond appear dull and lifeless.
Why aren’t all diamonds cut to ideal proportions?
To cut a diamond perfectly, a craftsman must cut away more than 50% of the rough diamond, so there is usually a tradeoff between cut and weight retention – and carat weight is still the primary determinant of a diamond’s value.
Color
Ironically, a diamond with the highest color grade is the diamond with the least amount of color. The highest grade is D, which indicates that a diamond is colorless, and therefore extremely rare and valuable. An E grade indicates minute traces of yellow that can only be detected by an expert. An F grade indicates slight traces of color. A diamond in the G-H range is near-colorless, with traces of yellow generally visible only when compared with whiter diamonds. I-J diamonds are also near-colorless, with color slighly detectable to the unaided eye. K-M, diamonds begin to display noticeable color.
Color differences in diamonds are very subtle. They are therefore graded under controlled lighting conditions and are compared to a master set of diamonds for accuracy. Although the presence of color diminishes a diamond’s value and cost, a bright, intense yellow-colored diamond is considered a “fancy” and is normally priced at a premium. Red, blue, pink, purple and green diamonds are also called fancies. They are rare and valuable, and priced much higher than yellows and cognacs.
Clarity
The vast majority of diamonds contain some impurities, called inclusions, which can detract from their beauty and impede light return. The size, number, type and location of the inclusions all factor into a diamond’s final clarity grade. The universal system for grading diamonds is the IF to I3 system, as charted below:
F and IF: F means internally and externally flawless. IF means internally flawless. F and IF diamonds are very rare and expensive.
VVS1 and VVS2: VVS means very, very slightly included. This means it is very difficult to see the impurities, even using a 10-power loupe. The numbers represent levels within this grade – VVS1s are cleaner than VVS2s.
VS1 and VS2: These diamonds are very slightly included, with impurities that are not visible to the unaided eye. VVS and VS diamonds are known as “eye-clean,” which means either a microscope or a 10-power loupe is necessary to see them.
SI1 and SI2: These diamonds are slightly included, which means the inclusions are visible under a 10-power loupe and might be visible to the unaided eye. Sometimes, a diamond is graded SI1 even though it has no more inclusions than an VS2 because the inclusions occur in the centre of the diamond, where they are more noticeable and might block light return. Other inclusions can be hidden by a mounting, thus having little effect on the beauty of a diamond.
I1, I2 and I3: These diamonds contain visible inclusions.
Carat Weight
Although many diamond aficionados consider clarity, color and cut as the most important criteria when choosing a diamond (they are the “beauty” factors) carat weight nevertheless remains the “C” most likely to determine value. Fortunately, it is the easiest characteristic to measure. The term carat is derived from the word carob. Carob seeds are similar in weight to each other, so diamonds were originally measured by comparison – one carob seed equaled one carat. A carat is divided into 100 points. So, a half-carat diamond is 50 points, and is expressed as 0.50ct.
Although it is true that the larger the diamond, the higher the price, it is not true that a one-carat diamond is simply twice the price of a half-carat diamond. Larger diamonds are found less frequently in nature, so a one-carat diamond actually costs much more than twice the price of a half-carat diamond of the same quality. Cut and mounting also make a difference in price.
Size is important, then, but it does not trump quality in terms of beauty. A one-carat diamond with high color and clarity values might be more beautiful, with more light return, than a two-carat diamond with lower clarity and color values, despite a much higher cost. And remember, the smaller your finger, the larger the diamond will appear!
Country of Origin
For decades, the 4Cs – color, cut, clarity and carat weight – have served as the universal guidelines for choosing a diamond. Today, there is a 5th C to consider: country of origin. When diamonds were discovered in Canada, they were not sold through the single-channel marketing (monopoly) arm of De Beers, now known as the Diamond Trading Company, and therefore did not become a part of the so-called “London mix” where diamonds are sorted according to quality and size. Most Canadian diamonds from the Ekati and Diavik diamond mines, located in Canada’s Northwest Territories, are therefore branded as Canadian diamonds. This concept became especially important during the controversy about “conflict” or “blood” diamonds, an issue brought to greater awareness by the 2007 film “Blood Diamond,” starring Leonardo Di Caprio. Today, diamonds from Botswana, Russia and other countries are also branded according to origin.
Canadian Diamonds
Canada’s diamonds were once buried under fields of ice 3,000 metres thick. As the glaciers melted, the indicator minerals that traditionally lead to the source were spread out over thousands of kilometres across the barren tundra. Finding these diamonds was one of the greatest challenges in the history of diamond exploration. In 1993, after more than a decade of gruelling exploration, Canadian geologist Charles Fipke discovered what is today the Ekati Diamond Mine in the Northwest Territories. As a result of this and subsequent discoveries, Canada has become the third largest supplier of gem quality diamonds in the world.
