Diamond Clarity

Diamond clarity measures the presence and severity of the internal marks, blemishes and flaws found in almost all diamonds. Whether natural or lab grown, it is incredibly rare to find a diamond totally free of such inclusions, but they do exist, and are known as ‘flawless diamonds’. The closer to flawless, the higher the diamond clarity, the rarer it is and the greater the cost.

Mined diamonds form deep within the earth over billions of years. Intense heat and pressure in the mantle encourage carbon molecules to crystallise and grow, picking up and trapping traces of other elements as they form. Small cracks and flaws within the diamond can form, also referred to as inclusions or blemishes if on the surface of the stone. The severity of these marks is measured on a diamond clarity scale.

The small marks and flaws found within diamonds are given the umbrella term ‘inclusions’, but there are many different types of diamond inclusions, caused by different phenomena. Some are more notable than others:

• Crystal - a minuscule diamond (or other mineral) within the diamond; sometimes coloured
• Pinpoints - tiny white or black crystals, appearing like a pinprick within the diamond
• Needle - an elongated, thin line of crystal
• Cavity or chip - usually caused by stressing a weak point during diamond cutting, a cavity in the surface
• Feathers - an internal crack or fissure, appears light and feather-like, sometimes transparent without magnification
• Clouds - a cluster of pinpoint inclusions, which can make a diamond appear milky or hazy
• Knot - a small crystal that breaches the surface of the diamond, like a tiny bump on the surface
• Graining - like you might find in wood, long streaks or lines that can look like scratches within the diamond, usually more visible from certain angles of the diamond
• Twinning wisp - these show the moment a diamond stopped then restarted growing; often two amalgamations of pinpoints, needles, feathers and cloud inclusions that point to separate phases of growth

A diamond's clarity grade is determined by the number, size, nature, position, and lack of inclusions and surface characteristics known as blemishes. Gemmologists analyse these factors under magnification to determine the diamond's final clarity grade. There are factors that affect the clarity it is graded:

• Size: The larger and more noticeable an inclusion is, the more it will impact the clarity grade. Larger inclusions are easier to see and therefore result in a lower clarity grade.

• Number: The more inclusions or blemishes a diamond has, the lower its clarity grade will be. Even if individual inclusions are small, a high concentration of them can significantly affect the grade.

• Nature: The type of inclusion also matters. Some inclusions, such as tiny crystals or feathers, are common and have varying impacts on the grade. However, inclusions that reach the surface (like chips or cavities) can be more detrimental to both the clarity grade and the physical durability of the stone.

• Position: The location of an inclusion is critical. Inclusions located directly under the table (the large flat facet on top of the diamond) are much more visible and have a greater negative impact on the clarity grade than inclusions located near the girdle or underneath the pavilion facets.

• Relief: Relief refers to how much an inclusion contrasts with the surrounding diamond material. Inclusions with high relief (those that appear dark or stand out sharply against the rest of the stone) have a more significant impact on the clarity grade than those with low relief, which may be translucent or difficult to detect.

Diamond clarity is often the best area to compromise on to optimise your budget without sacrificing visual beauty. Because most inclusions are microscopic, you can often save significantly by choosing a stone that is "eye-clean" rather than "flawless" under 10x magnification.

• Target the "Sweet Spot": For the best value, look for diamonds graded between VS2 and SI1. These stones are not technically flawless, but they will appear perfectly clear to the naked eye.

• The "Eye-Clean" Standard: The goal is to find an "eye-clean" diamond. This means that while a gemmologist might see tiny inclusions under a microscope, you and your partner will not be able to spot them in everyday lighting without the aid of a loupe.

• Avoid the "Lower Grade" Pitfall: Steer clear of clarity grades lower than SI1. At these levels, inclusions often become visible to the naked eye. Furthermore, heavy inclusions can block light from reflecting through the diamond, which will dull the stone's brilliance and fire.

• Don't Pay for What You Can't See: Without a professional microscope or loupe, even an expert would likely struggle to tell the difference between a Flawless (FL) diamond and a high-quality SI1 stone. By choosing the latter, you can reallocate your budget toward a larger carat weight or a higher colour grade.

While "Flawless" (FL) and "Internally Flawless" (IF) are technically the highest grades, they are extremely rare and carry a premium price tag that does not necessarily equate to better visual beauty. For most buyers, the "best" clarity is the one that looks perfectly clean to the naked eye while offering the best value for money. At Queensmith, we generally recommend aiming for VS1 or VS2 grades, which are eye-clean and offer a high standard of quality without the unnecessary cost of an Flawless grade.

That said, you’ll find lab diamonds are more readily available in top clarity grades than natural diamonds. A lab grown diamond’s clarity grade has less impact on the overall cost than with a natural diamond – so why not aim for a VVS lab diamond?

Clarity and colour are two distinct factors of the "4Cs" that influence a diamond's value and appearance:

• Clarity: This measures the internal and surface imperfections of a diamond, known as inclusions and blemishes.

• Colour: This measures the presence (or absence) of colour in a diamond. It assesses how "icy" or white a diamond looks, ranging from colourless (D) to noticeably yellow (Z).

Read more in our guide to the 4Cs here.

An "eye-clean" diamond is one that shows no visible inclusions or blemishes when viewed by the naked eye, without the use of a microscope or loupe. Finding an eye-clean stone rather than a flawless stone allows you to allocate more of your budget toward other characteristics like cut or carat weight, as you are not paying for microscopic details that cannot be seen in everyday wear.

In terms of appearance to the naked eye, there is effectively very little difference between a VS1 and a VS2 diamond; both are typically eye-clean. The primary difference lies in the size, nature, and positioning of the inclusions as seen under 10x magnification. A VS1 diamond will have inclusions that are slightly harder to see under a microscope than those in a VS2. While VS1 is technically a higher grade, a high-quality VS2 is often considered a smarter purchase for those looking to maximise their budget without compromising on the visual "cleanliness" of the stone.