Lab Created Diamonds on White Velvet | Lisa Robin


Diamond Clarity

Understand how diamond clarity is graded and how inclusions affect the clarity. Learn which clarity grade to choose, for an eye-clean diamond at the best price.

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What is Diamond Clarity?

About Diamond Clarity

We must first understand how diamonds are created in order to understand their clarity. As carbon is exposed to tremendous heat and pressure deep in the earth, natural diamonds are formed. Diamonds created in a lab occur in a vacuum chamber filled with hydrogen and methane. These gases are activated by energy sources—typically a microwave. As a result of this process, there can be a variety of internal characteristics called "inclusions," and external characteristics called "blemishes."

Small crystals can become trapped in a diamond when it’s forming. Sometimes as a crystal grows, it can develop irregularities in its atomic structure. The size, position and visibility of inclusions can have a significant impact on diamond clarity.

Clarity is evaluated by determining the number, size, relief, nature, and position of these characteristics, as well as how they affect the overall appearance of the stone. It is important to remember that no diamond is perfectly pure when determining what is the best clarity for a diamond. However, the closer it comes to purity, the better its clarity.

The Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific grades.

  • 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 (VS1 and VS2) Inclusions are observed with effort under 10x magnification, but can be characterized as minor
  • Slightly Included (SI1 and SI2) Inclusions are noticeable under 10x magnification
  • Included (I1, I2, and I3) Inclusions are obvious under 10x magnification which may affect transparency and brilliance

Diamond Clarity Scale graphic | Lisa Robin


Diamond clarity scale shows grading based on inclusions.

What are diamond inclusions?

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.

  • 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

Diamond clarity is graded based on a number of factors, including how clear inclusions or blemishes are under magnification, where and how they are positioned within the diamond, their size, color, and of course their number.

Grading diamonds is done from the top down, so when they are set in your ring you will see the marks you see when viewed under magnification. A diamond's clarity is graded under 10x magnification, so even those not visible to the naked eye are taken into account. Diamonds are graded according to their clarity based on their flaws, which are displayed on a diagram.

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Does diamond clarity impact sparkle?

From 'Flawless' to 'Slightly Included 1', any inclusions within the diamond will not generally affect its sparkle. Graded lower, however, diamonds may have inclusions that inhibit their sparkle. Large or heavy inclusions interfere with internal light reflection, reducing the amount of light leaving the diamond to reach your eyes. As a result, only diamonds graded 'Slightly Included 2' and lower will have inhibited sparkle.

What causes inclusions?

Small crystals can become trapped in a diamond when it’s forming. Sometimes as a crystal grows, it can develop irregularities in its atomic structure. The size, position and visibility of inclusions can have a significant impact on diamond clarity.

Can you determine the growth source of a diamond from its inclusions?

It is essential to note the growth origin of a diamond cannot be determined by the presence or absence of inclusions alone. For example, just because a diamond is free of inclusions does not mean it is lab-grown. Conversely, just because a diamond is highly included does not mean it is natural. Both natural and laboratory-grown diamonds can occur in all clarities.

Is it okay to buy a diamond with inclusions?

As inclusions are generally invisible to the average person, clarity is the best characteristic to compromise on when choosing a diamond. You can reduce the cost of your diamond by looking for VS2 to SI1 grades, which won't be flawless but will be clear to the naked eye. Inclusions should only be visible under a microscope in diamonds VS2 to SI1. When you look below SI1, you'll start spotting inclusions without magnification, and heavy inclusions can even reduce the stone's brilliance since they interfere with the light return.

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When assessing a diamond, experts look at its color, cut, carat weight, and clarity, to issue a certification. Learn what labs issue certificates and how to understand the certification report.

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