The 4C’s of Diamonds

Diamonds are graded according to the GIA’s ‘four C’s’ of diamond quality: carat, colour, clarity and cut. These qualities affect both the diamond’s appearance and its value. In line with the GIA’s grading system, The Diamond Shop specialises in diamonds graded D, E and F for colour, VS 2 to SI 1 for clarity and up to Triple Excellent for cut. Our lower-priced diamonds are graded H-I for colour and SI2-I1 for clarity. The guide below is designed to help explain what it all means.

Cut

The quality of the craftmanship.

Colour

How white or colourless the stone is.

Clarity

Denotes purity
and sparkle.

Carat

Specifies weight
and size.

What is Cut?

The cut of a diamond affects how much it sparkles.

When rating the cut of a diamond, experts look at all of the manmade aspects. These are the quality of the cut and how the light travels through the diamond as a result; how highly polished the end result is; and whether the diamond cutter has achieved perfect symmetry in the design. All of these affect how much the diamond sparkles – a poor cut will look glassy or dull, as light gets trapped or leaks out, while the better the cut the more glitter and ‘life’ it will appear to have.The highest cut grade is Triple Excellent, meaning that the cut, polish and symmetry are all rated Excellent; the lowest cut grade is Poor.

Shallow Cut

Light leaks out,  giving a glassy effect

Correct Cut

Maximum light is returned,  bouncing back to the viewer

Deep Cut

Light gets trapped, creating a lifeless appearance

What is Cut?

The cut of a diamond affects how much it sparkles.

When rating the cut of a diamond, experts look at all of the manmade aspects. These are the quality of the cut and how the light travels through the diamond as a result; how highly polished the end result is; and whether the diamond cutter has achieved perfect symmetry in the design. All of these affect how much the diamond sparkles – a poor cut will look glassy or dull, as light gets trapped or leaks out, while the better the cut the more glitter and ‘life’ it will appear to have.The highest cut grade is Triple Excellent, meaning that the cut, polish and symmetry are all rated Excellent; the lowest cut grade is Poor.

Shallow Cut

Light leaks out,  giving a glassy effect

Correct Cut

Maximum light is returned,  bouncing back to the viewer

Deep Cut

Light gets trapped, creating a lifeless appearance

Colourless
DEF
Faint Colour
KL
Near-Colourless
GHIJ
Noticeable
MNOPQR
Very Noticeable Colour
STUVWXYZ

What is colour?

In the diamond industry, colour means ‘whiteness’ or lack of colour.

The ideal diamond is one with no visible colour. This is the element most easily visible to the naked eye, and one that really comes into play when a stone is going to be set against a white metal like platinum. Hints of yellow or blue may become more visible in the corners of certain cuts, like the Princess.

The highest colour grade possible is a D, and the lowest is Z; grades A, B and C no longer exist, as it is believed that a true ‘perfect white’ does not exist in nature. Conversely, diamonds with an extremely strong colour are called ‘fancy colour’ diamonds, and are often more valuable than white diamonds; these are graded according to a slightly different colour scale.

What is colour?

In the diamond industry, colour means ‘whiteness’ or lack of colour.

The ideal diamond is one with no visible colour. This is the element most easily visible to the naked eye, and one that really comes into play when a stone is going to be set against a white metal like platinum. Hints of yellow or blue may become more visible in the corners of certain cuts, like the Princess.

The highest colour grade possible is a D, and the lowest is Z; grades A, B and C no longer exist, as it is believed that a true ‘perfect white’ does not exist in nature. Conversely, diamonds with an extremely strong colour are called ‘fancy colour’ diamonds, and are often more valuable than white diamonds; these are graded according to a slightly different colour scale.

Colourless
DEF
Faint Colour
KL
Near-Colourless
GHIJ
Faint Colour
KL
Noticeable
MNOPQR
Very Noticeable Colour
STUVWXYZ

What is clarity?

Clarity looks at whether there are any flaws or inclusions in the diamond.

A flawless diamond is one with no internal or external ‘inclusions’, which are comparable to natural birthmarks created when the diamond crystal was formed. These range from cracks to minerals and can affect how light behaves within the diamond, in some cases reducing its sparkle.

Diamonds are examined under 10x magnification during the clarity grading process, to ensure all internal characteristics are noted. The highest clarity grade is Flawless, and the lowest is I3.

Select a clarity grade
Flawless - No internal or external flaws. Very rare. Very expensive.
Internally Flawless - No internal flaws, slight external blemishes. Very rare. Premium diamonds.
Very, Very Slight Inclusions - Inclusions very difficult to see under 10X magnification. Rare and very high quality.
Very, Very Slight Inclusions - Inclusions very difficult to see under 10X magnification. Rare and very high quality.
Very Slight Inclusions - Inclusions difficult to see under 10X magnification. Less expensive than VVS diamonds.
Very Slight Inclusions - Inclusions difficult to see under 10X magnification. Less expensive than VVS diamonds.
Slight Inclusions - Inclusions easy to see under 10X magnification and might not be visible to the naked eye. Can be excellent value.
Slight Inclusions - Inclusions easy to see under 10X magnification and might be visible to the naked eye. Can be excellent value.
Included - Inclusions that are visible to the naked eye. Low cost promotional diamonds.

For the best value The Diamond Shop recommends clarities SI 1 to VS 1 with No black inclusions. Clarity gradings above VS 1 incur much greater costs with little perceived beauty in our opinion

What is clarity?

Clarity looks at whether there are any flaws or inclusions in the diamond.

Select a clarity grade
Flawless - No internal or external flaws. Very rare. Very expensive.
Internally Flawless - No internal flaws, slight external blemishes. Very rare. Premium diamonds.
Very, Very Slight Inclusions - Inclusions very difficult to see under 10X magnification. Rare and very high quality.
Very, Very Slight Inclusions - Inclusions very difficult to see under 10X magnification. Rare and very high quality.
Very Slight Inclusions - Inclusions difficult to see under 10X magnification. Less expensive than VVS diamonds.
Very Slight Inclusions - Inclusions difficult to see under 10X magnification. Less expensive than VVS diamonds.
Slight Inclusions - Inclusions easy to see under 10X magnification and might not be visible to the naked eye. Can be excellent value.
Slight Inclusions - Inclusions easy to see under 10X magnification and might be visible to the naked eye. Can be excellent value.
Included - Inclusions that are visible to the naked eye. Low cost promotional diamonds.

A flawless diamond is one with no internal or external ‘inclusions’, which are comparable to natural birthmarks created when the diamond crystal was formed. These range from cracks to minerals and can affect how light behaves within the diamond, in some cases reducing its sparkle.

Diamonds are examined under 10x magnification during the clarity grading process, to ensure all internal characteristics are noted. The highest clarity grade is Flawless, and the lowest is I3.

For the best value The Diamond Shop recommends clarities SI 1 to VS 1 with No black inclusions. Clarity gradings above VS 1 incur much greater costs with little perceived beauty in our opinion

What is clarity?

Clarity looks at whether there are any flaws or inclusions in the diamond.

A flawless diamond is one with no internal or external ‘inclusions’, which are comparable to natural birthmarks created when the diamond crystal was formed. These range from cracks to minerals and can affect how light behaves within the diamond, in some cases reducing its sparkle.

Diamonds are examined under 10x magnification during the clarity grading process, to ensure all internal characteristics are noted. The highest clarity grade is Flawless, and the lowest is I3.

FL
Flawless - No internal or external flaws. Very rare. Very expensive.
IF
Internally Flawless - No internal flaws, slight external blemishes. Very rare. Premium diamonds.
VVS1
Very, Very Slight Inclusions - Inclusions very difficult to see under 10X magnification. Rare and very high quality.
VVS2
Very, Very Slight Inclusions - Inclusions very difficult to see under 10X magnification. Rare and very high quality.
VS1
Very Slight Inclusions - Inclusions difficult to see under 10X magnification. Less expensive than VVS diamonds.
VS2
Very Slight Inclusions - Inclusions difficult to see under 10X magnification. Less expensive than VVS diamonds.
SI1
Slight Inclusions - Inclusions easy to see under 10X magnification and might not be visible to the naked eye. Can be excellent value.
SI2
Slight Inclusions - Inclusions easy to see under 10X magnification and might be visible to the naked eye. Can be excellent value.
I1
Included - Inclusions that are visible to the naked eye. Low cost promotional diamonds.

For the best value The Diamond Shop recommends clarities SI 1 to VS 1 with No black inclusions. Clarity gradings above VS 1 incur much greater costs with little perceived beauty in our opinion

What is carat?

The carat is the weight of a diamond, which in turn reflects its size.

One carat is equal to 200mg in weight; the higher the carat, the larger the diamond. However, there is one exception to this rule; unscrupulous jewellers will sometimes shape diamonds in a manner that maximises weight at the expense of a quality cut. It’s worth bearing in mind that carat isn’t everything – a diamond of superior cut, clarity and colour will always look more beautiful than one that is large but dull.

0.25ct
0.50ct
0.75ct
1ct
1.25ct
1.50ct
2ct
3ct
4ct
5ct

The Diamond Shop Recommends - A good way to save money when choosing carat weight is to opt for a diamond that weighs slightly less than the ‘magic’ numbers of 0.50ct, 0.75ct, 1.00ct etc.

What is carat?

The carat is the weight of a diamond, which in turn reflects its size.

One carat is equal to 200mg in weight; the higher the carat, the larger the diamond. However, there is one exception to this rule; unscrupulous jewellers will sometimes shape diamonds in a manner that maximises weight at the expense of a quality cut. It’s worth bearing in mind that carat isn’t everything – a diamond of superior cut, clarity and colour will always look more beautiful than one that is large but dull.

0.25ct
0.75ct
1.25ct
2ct
4ct
0.50ct
1ct
1.50ct
3ct
5ct

The Diamond Shop Recommends - A good way to save money when choosing carat weight is to opt for a diamond that weighs slightly less than the ‘magic’ numbers of 0.50ct, 0.75ct, 1.00ct etc.

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