The cut of a diamond determines how it reflects light, which is responsible forits sparkle or brilliance. A well-cut stone is made by a skilled professionalto the best proportions possible so that light will be reflected from each ofits mirror-like facets and disperse through its top.
Too shallow a cut will let light escape through the gem’s bottom, causing it to appear dull. On the other hand, too deep a cut will allow light to be lost through a diamond's sides, making it appear dark. Because a diamond with perfect colour and clarity could nevertheless have poor brilliance if it is not well cut, many gemologists consider this to be the most important property to note when choosing a diamond. Diamonds can carry grades of Excellent, Ideal, Very Good, Good, or Fair.
No two diamonds are alike. This precious rock’s most distinguishing characteristics are its inclusions - marks that are often invisible to the naked eye. However, under a jeweller's magnifying loupe or microscope they can look like crystals, tiny rivers, or clouds. Its clarity is determined by the presence or absence of inclusions – fewer inclusions mean better clarity – and how visible they are. The greater a diamond's clearness, the greater its brilliance and value.
A diamond categorised as internally flawless will have no inclusions, but this is extremely rare. Precious stones with very, very small inclusions are graded as VVS1 or VVS2. Those with larger inclusions are considered SI1 or SI2 and are commercial quality diamonds. If they’re visible to the naked eye, the gem is graded I1 to I3.
|IF||Internally Flawless. Very rare and beautiful diamonds|
|VVS1, VVS2 ||Very, very slightly included: Difficult to see inclusions
under 10x magnification. An excellent quality diamond.|
| VS1, VS2 ||Very slightly included: Inclusions are not typically visible
to the unaided eye. Less expensive than VVS1 or VVS2 grade, but still excellent
| SI1, SI2 ||Slightly included: Inclusions are visible under 10x
magnification and are noticeable to the experienced grader. A good value
| I1, I2, I3 ||Included from small inclusions (I1) to larger / many
inclusions (I3) that are obvious under 10x magnification and may affect
transparency and brilliance.|
Though diamonds come in a wide range of colours, tranparent gems have traditionally been considered the most valuable. Most are graded on a scale using the letters of the alphabet, from D (colourless), the best grade, through Z (a light yellow). It is difficult for the untrained eye to notice such variations in hue unless stones are being compared side by side.
The comparatively rare coloured diamonds are known as fancy and are also quite valuable. They range in hue from the more common yellow (also graded Z+ on the alphabetic scale) to pink, blue, green, red, and even black and white. Those that are graded D, E, and F tend to be the most expensive because of their rarity. However, any precious stone you buy should have a good balance of cut, colour, and clarity, so as to impart the most brilliance and dazzle possible. Grades H, I and J are considered near colourless stones.
A diamond's weight is measured in carats, with one carat being equivalent to 100 points. You will often see these gems being referred to as a 3/4-carat stone or a 75-point stone. Larger ones are often more highly valued, but size should not be the only consideration when looking to purchase.
It's fairly common to confuse diamond
cuts with shapes. The former describes a diamond's light performance,
dimensions and finish. The latter, however, refers to the overall outline of
the stone when viewed from the top.
Round is by far the most popular, followed by squared gems such as Princess,
Asscher and Emerald shapes.
Since all diamond shapes are very different, unique characteristics determine quality for each shape.
Below are the various diamond shapes:
| || |
The round brilliant shape is the modern version of the round which has been refined for maximum shine. It is by far the most popular and has the best angles to shine maximum brilliance.
|Princess||A square cut diamond that has refractive properties almost
near to that of the round brilliant.|
|Emerald||A more traditional shape, that has an old world elegance to
|Radiant||The radiant has more facets than a princess, but has the
corners trimmed like the emerald shape. This shape is not widely popular.|
|Heart||Hard to find due to low demand, but some people prefer a
heart shape diamond for sentimental purposes.|
Like the emerald, the marquise is a traditional shape. This is probably the fourth most popular behind the round, princess and oval.
|Pear||Mostly used in pendants, the pear shape diamond looks like a
tear drop shape and has fairly good proportions to refract light well. |
Diamonds, as the hardest substance on earth, are resistant to damage. However, they are set in different metals, and care will vary from piece to piece. The girdle can be chipped by a hard blow, making a protective setting extremely important. It is a good idea to have them cleaned once a year by a professional jeweller, at which time the security of the setting can be checked as well. They should be stored in a soft cloth pouch to ensure that the stone will not scratch other jewellery.