Types of Diamonds

Types of Diamonds

Like snowflakes, no two diamonds are exactly alike. They are all unique and that is pretty amazing. To help diamond customers know exactly what they were about to purchase, a grading system, set up by the GIA (Gemological Institute of America), was implemented to evaluate diamonds based on four aspects.

These four grading systems are known as the "4C's" and is the universal method for assessing the quality of any diamond, anywhere in the world.

The 4C's are Colour, Clarity, Cut and Carat.


Diamonds have various tints and are graded on how colourless they are. Starting from grade D, being colourless or exceptional white which are rarer and so more valuable, up to grade Z, being light yellow. Diamonds at Bicknells are exceptional white+ (D) through to white (H). These all have excellent diamond colour quality and our knowledgeable team can also help you find that is best suited for yourself. Other diamond colours available are known as "fancy" diamonds which are natural and come in yellow, orange, red, green, blue, pink to purple, brown, grey and black.

view DiamondColour.pdf  (Adobe Reader or similar required)
For more information on colour and clarity, click here.



Because they are formed deep within the earth, under extreme heat and pressure, virtually all diamonds contain "birthmarks" or small imperfections inside the diamond (inclusions), or on its surface (blemishes). They are graded using the following scale; Finding a diamond that is flawless (FL) is really quite rare and will certainly be a lot more expensive. Fortunately, nearly all of the above clarity scales are graded while looking through a small magnification device called a loupe. This means, although they have inclusions, they are not visible to anyone without a loupe. So more than likely you or anyone else will never see these. The only grade with eye visible inclusions being the I1-I2-I3. We recommend a SI1-SI2 or VS1-VS2 grade as a good starting point.

view DiamondClarity.pdf  (Adobe Reader or similar required)
For more information on colour and clarity, click here.



The cut of a diamond refers not to the shape but to the polish and symmetry which are two important aspects. The polish describes the smoothness of the diamond's facets and the symmetry refers to alignment of the facets. With poor polish, the surface of a facet can be dulled and may create blurred or dulled sparkle. The cut is important as it determines the diamond's reflective qualities and directly influences its value. If you want your diamond to really dazzle, then we recommend a Round Brilliant, Princess or a Phoenix Cut diamond. These particular diamonds will show more sparkle than others because of the way their cut has been applied which allows light to refract better.
The shape of a diamond refers to the geometrical outline. There is a variety of diamond shapes available today including princess cut, emerald cut, oval, marquise, pear, cushion, heart and Asscher. While the choice of shape can also reflect the personality of the wearer. Round brilliant is the most popular due to its pleasing appearance and traditional shape.

view DiamondCut.pdf  (Adobe Reader or similar required)


Carat weight

Carat (ct.) refers to the unique unit of weight measurement used exclusively to weigh diamonds and other gems. A carat is often confused with visual size even though it is actually a measurement of weight. Exact measurement of carat weight is important because slight difference in carat weight can have a large impact on price. Each diamond is weighed on scales that measure up to 1/100,000 of a gram. One carat equals 0.2 grams or 100 points.Note: It is important to remember that diamonds of the same carat weight can vary in size. For example, two 1-carat round diamonds can have different widths or heights. Even if these two stones weigh the same, the deeper cut one will appear smaller when it's set in a ring, while the shallower cut diamond will seem larger.
view DiamondCarat.pdf  (Adobe Reader or similar required)

For more information

When buying any diamond piece from Bicknells ask to see its certificate which will give you reassurance of its high quality and authenticity. We also welcome you to our showroom in the Jewellery Quarter, Birmingham where you will be looked after by one of our friendly team members who can offer plenty of advice and even a tea or coffee! Our in-house diamond grader will be able to give you valuable assistance too if required. Please contact us if you need any more information or if you would like to book an appointment. We will be more than happy to answer any of your questions.