Determining which is more important out of a diamond carat weight or cut is a question of quality vs quantity.
If you’re in the market for a diamond or diamond jewellery, there’s a good chance you’ve come across the 4Cs. The 4Cs refer to the weight (carat), shape (cut), colour, and clarity of a diamond and are graded on the Gemologist Institute of America (GIA) scaling systems. Carat weight and cut make up half of the 4Cs and are factors in working out the value of a diamond.
We often hear that heavy diamonds make up a considerable amount of a diamond’s cost, which is still the case - to an extent. However, a diamond cut is regarded as more important in terms of visual appearance and market value.
Let’s unpack the carat weight and cut of a diamond and how these qualities affect value.
The carat weight is a unit of measurement for the weight of a diamond and is used globally. A single carat is the equivalent of 0.200 grams, or 200 milligrams, and is divided into 100 ‘points’ – allowing for exact measurements to the hundredth or thousandth decimal place. It’s important not to confuse weight with size when measuring the value of a diamond – as the diamond’s size is not valued the same as its weight.
Generally, the higher the carat weight, the higher the diamond’s value. A diamond's price is determined by how rare the stone is deemed to be; a large carat weight reflects a diamond’s rarity.
The price of a diamond can increase dramatically between tiny changes in weight. For example, a carat weight of 0.98 can cost significantly less than a diamond with a carat weight of 1.02. So, while you won’t be able to tell the difference between these two diamonds visually – you’ll undoubtedly notice the differences in cost.
An interesting point to note is that diamonds are not priced linearly. This means that a one-carat diamond will cost considerably more than two half-carat diamonds of the same quality.
In Australia, the most common carat weight for a diamond ring is 1.0, with 1.25 and 1.5 carat weights also extremely popular. With that being said, determining what a normal or good carat weight for a diamond ring is entirely dependent on you and your partner's style, preferences, and budget.
Diamond cut involves a jeweller cutting into a diamond to change its shape and finish – ultimately affecting how the diamond interacts with light. In short, the cut of a diamond is what makes a diamond sparkle. Diamond cuts are graded on its face-up appearance (brightness, fire, scintillation), design (weight ratio and durability), and craftsmanship (polish and symmetry), which will determine the allure and attractiveness of the diamond. The most common diamond cuts include round, oval, emerald, pear, or heart.
A diamond cut value is graded on the GIA Cut Scale, ranging from Poor to Excellent. A diamond sitting on the higher end of the scale generally means that more experienced craftsmanship went into the cut. A high cut scale grade also means that a larger portion of a diamond was disposed of during the cutting process.
A diamond that is cut well has 57 or 58 facets (the flat surfaces on top and underneath a diamond), allowing the light to bounce off the surfaces to create a brilliant visual appearance. A quality diamond cut will be symmetrical and have a shining finish. When a diamond is cut poorly, visual appearance is hindered by shape and sparkle and the stone will drop significantly in price, no matter the carat weight.
When a cut is in high demand, the price increases higher than other shapes. When a diamond cut is in higher demand due to trends and popularity, the need for manufacturing increases, increasing manufacturing costs. For example, a heart diamond and a round diamond have the same number of facets; however, a heart cut is less popular than a round and costs 15 to 20% less.
A diamond cut is more important than carat weight. This is because a high-quality cut can make a diamond look visually appealing and brilliant, regardless of size or weight. On the other hand, a poorly cut diamond will not look visually brilliant, even if the diamond is large.
Consider the visual appearance when determining whether carat weight or cut is more important to you. For example, you won’t notice the size difference between a 0.90 carat diamond and a 1.00 carat diamond, whereas you will notice if a diamond is asymmetrical or if its sparkle is hindered by a poor cut.
The 4Cs are the characteristic qualities of a diamond which evaluate its value. Determining which of the 4Cs is more important largely depends on your personal preferences. If you are drawn to the rarity of a heavier diamond or prefer a diamond with higher clarity – the answer to “Which of the 4Cs is most important?” changes.
In saying this, when looking at the visual appearance of a diamond and its value in the market – the most important out of the 4Cs is the cut. The cut determines the direction that the light will travel – enhancing the sparkle and brilliance of a diamond.
