Diamond Education

The 4 C's

Diamond Anatomy & Cut Quality

The term diamond cut refers not to a diamond’s shape, but the balance of proportions achieved by the diamond cutter. Diamond cut is essentially all about how well the facets of the diamond interact with light.

A cut grade is given only to a round brilliant diamond. Being the most sought-after diamond shape, GIA has spent decades developing a system to grade the cut quality of round diamonds.

While everyone has their favourite combination of the 4 Cs – colour, clarity, cut, and carat weight — cut has the greatest influence over a round diamond’s brilliance, determining what we call sparkle. Excellent and very good cut diamonds have the highest light return as well as the highest price tag due to their rarity.

Table: The largest facet of a diamond or gemstone. It is usually the surface area at the very top of the stone.

Crown: This is the top section of a diamond, where the girdle joins the table.

Pavilion: The pavilion is the bottom part of the diamond that connects the girdle to the culet. A pavillion that is too shallow or deep will result in light escaping from the side or bottom of the stone, as opposed to the desired finish of light reflecting out from the top of the stone.

Girdle: The girdle sits between the crown and the pavillion and defines the perimeter of the diamond. We recommend a ‘medium to slightly thick’ girdle. Thick girdles are undesirable because they add additional weight to the stone, without increasing the appearance of the stone size. A thin girdle makes the diamond more susceptible to damage.

Culet: A small facet at the bottom end of the gemstone, often ending in a tip or point.

Depth: The height of a gemstone measured from the culet to the table, noted in a percentage.

Understanding the 4 C’s of Diamonds Shopping

The diamond cut is the most important element to consider when buying a diamond. The cut is the biggest factor in creating sparkle and fire, and without a high cut grade even a diamond of high quality can appear dull and lifeless. A diamond cut poorly and too deep can face-up smaller than it actually is.

Clarity

Diamond clarity is the assessment of small imperfections on the surface and internally. The surface flaws are called blemishes, and internal defects are known as inclusions. These tiny, natural blemishes and inclusions are microscopic and do not affect a diamond’s beauty in any way. Diamonds with the least and smallest inclusions receive the highest clarity grades.

Diamond Clarity Descriptions

Flawless (FL): No inclusions and no blemishes visible under 10x magnification
Internally Flawless (IF): No inclusions visible under 10x magnification
Very, Very Slightly Included (VVS1 and VVS₂): Inclusions so slight they are difficult for a skilled grader to see under 10x magnification
Very Slightly Included (VS₁and VS₂): Inclusions are observed with effort under 10x magnification, but can be characterised as minor
Slightly Included (SI₁and SI₂): Inclusions are noticeable under 10x magnification
Included (I₁, I₂, and I₃): Inclusions are obvious under 10x magnification which may affect transparency and brilliance

Cut

Diamond Cut Measurment

Brilliance

The brightness created by the combination of white light reflections inside and on the surface of the stone. In order to be brilliant, a diamond requires more than just bright light return. It also needs contrast, so that the light produced by the diamond appears brighter. When the diamond is moved, it ‘scintillates’ which we explain further below.

Fire

The spread of white light which appears as flashes of all the colours of the spectrum. You’re more likely to see flashes of rainbow colours in a darker, more dimly lit environment that have fewer light sources.

Scintillation

The flashes of light and dark, and intense sparkle a diamond emits when the diamond or its light source is moved. Scintillation is most visible in well-lit environments.

Color

Diamond colour is a grading system that determines the level of colour present in a diamond. In fact, colour grade determines the absence of colour in a diamond. White diamonds are graded from D (colourless) to Z (light yellow), a classification scale created by the Gemmological Institute of America. As you go from D – Z, the diamond will go from having an icy, colourless appearance to exhibiting a brown or yellow tint.

Diamond Color Descriptions

The most frequent diamond colour we see amongst our customers is F. This is closely followed by E and G.

E and F colours are in the colourless category while G is in the near colourless category – all diamonds in the colourless and near colourless category will appear bright and white in appearance.

D : Absolutely Colourless : The Highest colour grade which is extremely rare

E : Colourless : One Minute trace of colour can be detected by an expert Gemologist

F : Colourless : Slight Colour detected by an expert Gemologist, But still considered A “Colourless” Grade. A high quality Diamond.

G – H : Near – Colourless : Colour noticeable when compared to diamonds of better grade. But these grades offer an excellent value.

I – J : Near – Noticeable Colour : Colour Detected

K – M : Noticeable Colour : Light Yellow Or Light Brown

N – Z : High – Noticeable Colour : Yellow Or Brown

Carat (Size)

Diamond carat is often misunderstood and refers to a diamond’s weight, not necessarily its size. When comparing diamond carat sizes, take a diamond’s cut into consideration as well: a high-carat diamond with a poor cut grade may look smaller, often cut deeper, than a diamond with smaller carat weight and a better cut.

What is diamond carat weight?

Before grams and ounces, diamonds were weighed using carobs, a long green bean with seeds inside. The beans were nearly identical in size, making them ideal for Mediterranean traders to use when weighing gemstones. One seed equalled one carob, which is likely where the term carat originates.

Carat is often confused with the size of a diamond even though it’s actually a unit that measures its weight. Today, one carat is equal to 0.2 grams.

How does diamond carat weight impact price?

Because larger diamonds are more rare, the heavier the diamond, the higher the price.

Though price increases aren’t steady—they can increase exponentially with carat weight. For example, a 1 carat diamond would be valued higher than two 0.50 carat diamonds of the same quality.

How does diamond carat weight impact price?

Because larger diamonds are more rare, the heavier the diamond, the higher the price.

Though price increases aren’t steady—they can increase exponentially with carat weight. For example, a 1 carat diamond would be valued higher than two 0.50 carat diamonds of the same quality.

So does bigger mean better when it comes to diamonds?

Just because a diamond is bigger, doesn’t mean it’s better.

The right diamond isn’t just based on one factor but a combination of all 4 Cs (carat, cut, clarity and colour). When choosing a diamond, focus on the quality that’s most important to you, then work to balance the remaining three.

Diamond Fluorescence

Approximately 30% of all diamonds naturally emit a glow under ultraviolet light. This is called fluorescence. It is caused by an anomaly in a diamond’s crystal structure, and can range from None to very strong. Fluorescence is different from a diamond’s colour grade, and typically can’t be seen in natural light.

Effect Of Fluorescence In Pricing Of A Diamond

Diamonds with no fluorescence are priced at a premium because the quality is sometimes perceived to be a defect. Generally, diamonds with faint to medium fluorescence are the more cost-effective options; by not paying the premium for a fluorescence-free diamond, you can invest in a higher cut or clarity grade (both of which have much greater impact on the diamond’s appearance).

Effects Of High Fluorescence In A Diamond

A highly fluorescent diamond may actually appear whiter if it also has a colour grade of Faint Yellow (K and L) or Near Colourless (I and J) — the blue tones of fluorescence subtly balance out the yellow colour tones. This can result in a diamond that looks as if its colour grade is higher than it really is.

Colours Of Fluorescence

While the majority of diamonds with fluorescence exhibit a blue tone under ultraviolet light, other colours are possible. Rare yellow, orange, green and red fluorescence has been documented. These hues can increase the desirability of fancy coloured diamonds if they complement their primary hue. For example, a fancy yellow diamond with yellow fluorescence will have an intensity that appeals to many diamond customers, potentially raising the value of the stone.