Use our helpful guides to learn about diamonds and how to choose the perfect diamonds for your diamond jewellery. If you have questions or wish to discuss further with one of our personal jewellers, please feel free to email
Diamond Carat Weight
Fancy Coloured Diamonds
Diamond Carat Weight To MM Width
Diamond Carat Weight
The diamond carat refers to the weight of the stone instead of the size. A carat (1.00ct) is divided into 100 points and weighs 0.20 grams. For example 25 point diamond is often referred to a quarter carat or 0.25ct.
Carat weight is often confused with size of a diamond but two diamonds of equal weight and shape can appear a completely different size based on the depth of the stone and the quality of the cut.
The term ‘carat’ comes from the historical use of carob seeds as a unit of measurement. Carob seeds were used due to their near uniform size and weight, creating a relatively accurate form of measurement.
Carat weight is one of the most important factors in determining the value of a diamond, however this does not mean that all equal carat weight stones are the same price. Other factors such as colour, clarity, cut and certification are also taken into consideration when determining the value of a diamond.
Use the below GIA guide to compare the sizes of different carat weights of diamonds. Please note diamond images are for reference only and may vary based on screen size.
Choosing the perfect diamond shape can be difficult, everyone has a personal favourite. Below is a quick guide outlining the most popular diamond shapes available:
Round Brilliant Cut
The round brilliant cut diamond is the most popular diamond shape. A round brilliant cut diamond has between 57-58 facets, arranged specifically to provide a balanced return of light and encourage light refraction. Each facets is calculated exactly to ensure fire and brilliance. This is the only shape of diamond that currently had cut grading, see diamond cut for further information.
Oval cut diamonds gave been gathering popularity over the past few years. With a similar facet layout as a round brilliant cut, the oval cut offers a similar sparkle and brilliance. This shape is favoured by some due to its flattering, lengthening appearance on the hand. Each oval cut diamond is different and the length to width ratio can be selected based on the desired shape.
Emerald cut diamonds are one of the most popular fancy shapes. These diamonds have fewer, but, larger facets than round brilliant cut diamonds. Thus providing large flashes of light rather than a constant glittering. Due to the open facets of an emerald cut diamond, we recommend focussing on higher clarity grades to prevent inclusions being noticeable. These statement stones are popular among celebrities.
There are two types of cushion cut diamond. The cushion brilliant cut and the cushion modified brilliant cut. As suggested in the name, the cushion brilliant cut diamond has a similar facet layout to the round brilliant cut diamond. Whereas, the cushion modified brilliant cut has additional facets. This style is often referred to as "crushed ice" due to its appearance.
The princess cut is sometimes referred to as square modified brilliant cut due to the similar facet pattern. This cut offers a combination of sharp edges with the sparkle and brilliance associated with round brilliant cut diamonds. These stones can have up to 78 facets. Not all princess cut diamonds are exactly square, so it is important to pay attention to the length to width ratio of the diamond.
The asscher cut diamond is often referred to as a modified square emerald cut diamond. The facet pattern is similar to that of an emerald cut, with large open facets offering bold flashes of light. Similar to the princess cut, these are not always square so it is important to view the stone or pay attention to the length to width ration. As an emerald cut, we recommend focussing on the higher clarity gradings as inclusions are easier to see with the open facet style.
The radiant cut diamond is known for it's cut corners. Combining the shape of an emerald cut with the brilliance and sparkle of a round brilliant cut. Radiant cut diamonds are particularly common in fancy coloured diamonds, as the facet pattern intensifies the colour. Radiant cut diamonds are available in different width to length ratios, meaning some diamonds are long rectangles, whereas others are perfectly square.
Pear shape diamonds are popular for their teardrop shape. With a similar facet layout to a round brilliant cut, these stones offer a unique shape alongside fire and brilliance. Pear shape diamonds are available is different ratios, so the teardrop shape can be long and slim or short and wide. The perfect shape is personal, we would recommend viewing pear shape diamonds so as to find your perfect proportions.
Marquise diamonds have an elongated shape, making them flattering on the finger. Due to the cutting style of this unique diamond, the stone can appear much larger than other stones of a similar carat weight. The facet pattern mimics a round brilliant cut diamond, ensuring the stone glistens.
The heart shape diamond is often seen as the most romantic cut of diamond. With a similar facet pattern to a round brilliant cut diamond, the heart shape offers fire and brilliance. Each heart shape diamond is unique and viewing is essential, symmetry and shape appeal can make a real difference to the stones appearance.
Fancy Coloured Diamonds
Diamond fluorescence is a factor that can affect the value of a diamond and sometimes the appearance. It refers to whether the diamonds fluoresces under an ultraviolet light.
Image courtesy of GIA.edu