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All About Diamonds

All you need to know about
diamonds before deciding
which to buy.

Diamonds & Light

Diamonds are loved because of the
scintillating plays on light. When
light enters the diamond, it refracts off
the diamond's surfaces. This light leaves the diamond either as white light – increasing its brilliance – or is separated in its spectral
colours (colours of the rainbow), also described as fire.

Any movement of the diamond, the light source or the viewer causes the diamond to sparkle with flashes of white and coloured light, which is known as scintillation.

The manner in which light
interacts with a diamond depends on the
diamonds proportions.

Ideal Proportions

For round brilliants, most table percentages are between 50 percent and 66 percent, most crown angles are between 25° and 35°, and most pavilion depths are between 42 percent and 44 percent. As brightness and scintillation are more important in small stones, variations in proportions are much less of a concern. Proportional variations play a more significant role in fancy cut diamonds. For example, tables over 70% and pavilion depths over 50% are more common for emerald cuts, marquises, ovals and pears. These variations may sometimes also affect weight estimates. The appearance, and therefore value, of a diamond can be affected significantly by proportional variations. Two diamonds similar in terms of colour, clarity and weight can appear very different due to their proportions: one may appear larger or brighter than the other.


Table Percentage
50% - 58%
Crown Angle
25° - 35°
Pavilion Depth
42% - 44%

Brightness & scintillation are more important.
Proportional variations are more signficant.

One may appear larger or brighter than the other due to the difference in their proportions.

Diamond Finish

A diamond's finish consists of two qualities: polish and symmetry.

The overall condition of the facet surfaces of a finished diamond.

Includes the precision of its proportions and the balanced placement of its facets from one side to the other.
Individual finish characteristics might be difficult to detect, but they make the difference between good and superb cutting. It takes a considerable investment of time and money to produce diamonds with superb polish and symmetry. Large, high-quality stones are worth that investment, so they usually have the best finish. Hattons only carries diamonds with the top two grades of polish and symmetry: Excellent and Very Good.


Because of its hardness, diamond will take and keep the best polish of any gem. Good polish is essential for maximum brilliance, fire, and scintillation. Diamond graders describe the quality of a diamond's polish as excellent, very good, good, fair, or poor, based on many possible combinations of these characteristics:
In polish grading terms, excellent means “superior,” not “perfect,” so—for example—a diamond with just a few very hard-to-find polish lines or tiny blemishes would be rated excellent.
Very Good
If a stone has only faint polish lines or insignificant blemishes in inconspicuous places, its polish is very good.
When transparent polish lines on the crown are visible through the pavilion, when only a few facets show burn marks, or when there are several small blemishes, the polish is good.
Obvious polish lines, burn marks on several facets, or noticeable blemishes put a stone in the fair category.

Polish lines, burn marks, or blemishes that reduce transparency call for a poor rating. You'll usually see a poor finish rating on diamonds with low clarity. Hattons does not carry diamonds rated poor in polish grading.


A symmetrical diamond has an even display of brilliance, fire, and scintillation. Most diamonds exhibit some symmetry variations. Diamonds are examined for symmetry variations under 10X magnification. Like polish grading, graders use five terms to describe symmetry: excellent, very good, good, fair, and poor.
Diamonds with excellent symmetry might have one or two tiny, inconspicuously placed extra facets, a few very slightly misshapen facets, or a few facets that do not point precisely.
Very Good
A few small extra or misshapen facets, slight pointing problems, or very slight misalignment between the crown and pavilion.
If a diamond has a table or culet that’s very slightly off-center, several extra facets, minor facet shape and pointing problems, and crown-to-pavilion misalignment, its symmetry is good.
When the table or culet is slightly off-center, the girdle is slightly wavy, there are a number of extra facets, misshapen facets and pointing problems are noticeable, or crown-to-pavilion misalignment is fairly easy to see, the symmetry is only fair.
Poor: If any – or all – of these symmetry variations are very easy to see under 10X magnification, the diamond gets a poor rating. Hattons does not carry diamonds rated poor for symmetry.