The clarity of the diamond refers to any imperfections it may have within itself or on the surface. Because diamonds are natural items formed deep within the Earth under great pressure and heat, truly flawless diamonds are extremely rare. Diamonds will all usually include inclusions (imperfections inside the stone) or external blemishes but what matters is how the imperfections affect the appearance of the diamond and how the light reacts inside it.

Inclusions can come in the form of dark carbon or light mineral deposits or ‘feathers’, which are cracks within the structure of the stone. These cracks only affect the durability if the cracks reach the surface of the stone.

Below are some illustrations demonstrating how the inclusions might appear and their associated gradings:



The clarity of the diamond can have a real impact on its sparkle and appearance. The fire and brilliance of a diamond are created through the reflection and refraction of light through the facet pattern. Any visible inclusions in the stone can affect the movement of light within the stone and can even sometimes be seen by the naked eye, which can really spoil the appearance of the stone.

The GIA have come up with a grading system that most jewellers adhere to because it makes the grading system really clear:


The further to the left on the scale, the more valuable the stone is, however clarity is still an area you can compromise on if you are working to a tight budget. Because diamonds are a natural product, these inclusions can actually give something extra to the stone. This is why it is so important to see a diamond before committing to having it set in your piece of jewellery – preferably a selection of stones so you can pick your favourite. For example, three H SI diamonds next to each other will have individual personalities even if they are rated the same as these grading systems, although a helpful guide, attempt to quantify diamonds which cannot be totally quantified.


For more information, visit my blog post all about the 4 C’s of Diamonds