Diamond Clarity Grades Explained

Clarity describes how many natural internal and surface features a diamond has. Understanding the grades helps you avoid overpaying for perfection you cannot see, while still choosing a stone that looks clean and bright.

What is diamond clarity?

Diamonds form under intense heat and pressure, and most contain tiny natural characteristics. Internal features are called inclusions, and surface features are called blemishes. Clarity grading assesses the number, size, position, nature and visibility of these characteristics under 10x magnification.

The clarity scale

The Gemological Institute of America (GIA) scale has 11 grades across six categories. Other laboratories use similar scales, though their standards can vary.

• Flawless (FL): no inclusions or blemishes visible under 10x magnification.
• Internally Flawless (IF): no inclusions visible under 10x, but minor surface blemishes may exist.
• Very, Very Slightly Included (VVS1, VVS2): inclusions are extremely difficult to see under 10x.
• Very Slightly Included (VS1, VS2): inclusions are minor and can be seen with effort under 10x.
• Slightly Included (SI1, SI2): inclusions are noticeable under 10x and may sometimes be visible to the eye.
• Included (I1, I2, I3): inclusions are obvious under 10x and are likely to be visible to the eye and may affect durability or brilliance.

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What are inclusions?

Common types include small crystals, feathers, which are tiny internal cracks, clouds, which are groups of tiny pinpoints, and needles. Their effect depends on their size, colour, position and how easy they are to see. A small dark inclusion in the centre of the stone is more noticeable than a pale feather near the edge.

What does eye-clean mean?

An eye-clean diamond has no inclusions visible to the unaided eye at a normal viewing distance. Many diamonds in the VS and some in the SI range can be eye-clean, which means you may be able to choose a lower grade and spend the difference elsewhere, such as on cut quality. The only way to know is to inspect the specific diamond with clear photographs, video or in person.

Clarity and the shape of the diamond

Step cuts such as emerald and Asscher have large open facets that can show inclusions more easily, so many buyers choose a higher clarity grade for these shapes. Brilliant cuts such as round, oval and cushion tend to hide inclusions better because of their faceting.

Do larger diamonds need higher clarity?

Generally, yes. As a stone gets larger, inclusions are easier to see, so buyers of larger diamonds may choose a higher grade. For small stones, a lower grade may still look clean.

Reading the clarity plot

A grading report usually includes a plot, which is a diagram showing the location and type of the main inclusions. Use it to see whether the inclusions are near the centre, close to the edge or under a prong where they may be hidden. Two diamonds with the same grade can look different because of where the inclusions sit.

Clarity and durability

Some inclusions, such as large feathers near the edge, can affect a diamond's durability, especially if they reach the surface. If you plan to wear the ring every day, ask about any inclusions that could be a weak point and consider a protective setting.

Clarity and price

Prices generally rise with higher clarity grades, and the steps at the top of the scale, such as flawless and internally flawless, are especially expensive. Because many differences at the top are not visible without magnification, paying for them may not change how the diamond looks in everyday wear.

How clarity fits with the other Cs

Clarity is one of the 4Cs, along with cut, colour and carat weight. Cut has the strongest effect on sparkle, so it is often prioritised, with clarity chosen at a level that looks clean to your eye. Our diamond 4Cs guide shows how these factors work together.

Lab-grown diamonds

Lab-grown diamonds are graded on the same clarity scale. They can also contain inclusions, though the types may differ from those in natural stones. Check the grading report for the specific diamond.

How to choose a clarity grade

1. Decide on the shape and cut quality you want.
2. Look for diamonds in the VS to SI range that are eye-clean.
3. Check images, video and the clarity plot to confirm.
4. If a stone is larger or an emerald cut, consider a higher grade.

Buy with confidence

Always buy a diamond with an independent grading report and make sure the report matches the stone. You can compare diamonds in different clarity ranges in our diamond jewellery collection.