Diamond clarity

What is diamond clarity?

Diamond clarity is the assessment of small imperfections on the surface and within the stone. Surface flaws are known as blemishes, while internal flaws are known as inclusions. Inclusions can obstruct a diamond's ability to refract and return light -- so the poorer the clarity, the less a diamond will sparkle.

Gemologists often use the term “internal characteristics” instead of imperfections or flaws as they give a natural diamond its unique character. Natural diamond is a diamond that was grown in the earth’s crust over the course of billions of years. They’re formed 90 miles below the earth’s surface, in high-pressure, high-temperature conditions. Underground volcanic eruptions push these diamonds to the surface, where they wait to be discovered.

This process can naturally result in a number of these internal characteristics and external blemishes, and due to their rarity, diamonds with the fewest and smallest inclusions have a higher clarity grade, matched with a higher price. 

How is diamond clarity measured?

In lab-grown diamonds the same basic principles of extreme pressure plus heat result in the same inclusions, so they are measured in the same way. 

Diamond clarity is measured by assessing the stone for inclusions and blemishes  under 10x magnification, and is graded within a range from Flawless to Included.  

Every Lightbox lab-grown diamond has been measured as VS or better. This means the stone has minor inclusions that are difficult to see at 10x magnification, and cannot be seen by the naked eye. 

The Lightbox quality inscription

All Lightbox lab-created diamonds over 0.20 carats are also inscribed with our tiny mark of quality. It’s invisible to the naked eye, but detectable by a 10x magnifying loupe.

This mark clearly identifies all Lightbox stones as being lab-grown, and is an intentional mark of quality that does not contribute to our grade of the stone, and can only be seen with magnification.


  • Our environmental commitment

    At Lightbox we are big on transparency and our commitment to reducing the footprint of our stones is a huge part of this. See more on how we grow our stones with 100% renewable energy.

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  • Visit the lab

    Explore the Lightbox Lab in Portland, Oregon, home to our world-leading technology producing up to 200,000 carats a year, each one always VS clarity, very good cut and now 'grown in the USA'.

  • Lab-grown FAQs, answered.

    Our leading technology means our lab-grown diamonds are among the highest quality you can find. Learn more about the science behind the sparkle with our guide to lab-grown diamonds.