The anatomy of a diamond

Most people know that diamonds come in many different shapes. Whilst the round brilliant cut is the most common and most popular cut, other shapes are known as “fancy cuts” and include shapes like ovals, cushions, princess cuts and pear cuts. But despite their differing shapes, they all have a number of common physical characteristics, what we can call the “anatomy of a diamond” or the different parts of the diamond.

Any cut and polished diamond can be divided into three main components, namely the crown, the girdle and the pavilion. The quality of the cut can be gauged by the relative proportions and measurements of these 3 components. A round brilliant diamond has 57 facets and whilst each facet is important, what’s more important is how these facets relate to each other to give an overall stone appearance.

Let’s look at each of the 3 main parts in detail to help you better understand what to look for when you’re buying a diamond.

The crown of a diamond

This is essentially the top part of a diamond, the part that you see most obviously when the gem is set in your jewellery. The most obvious part of the crown is the table of the diamond, the flat top part of the stone. The proportions of the table are incredibly important relative to the diameter and depth of the gem. Other parts of the crown include the star, bezel and upper girdle facets.

Salt and pepper diamonds South Africa
Round cut salt and pepper diamonds showing the crown, girdle and pavilion parts of the diamond.

The girdle

The girdle is the middle section of the diamond that runs all the way around the gem, separating the top from the bottom (in layman’s terms). The girdle has a very important function as the setting edge of the gem and ideally, should be medium to slightly thick to provide for optimum weight distribution in the diamond as well as for ease (and safety) of the stone setting.

Parts of a black diamond
Round black diamonds showing fewer facets than traditional round brilliant white diamonds. You can also see how girdle thicknesses vary; the diamond on the left has a thinner girdle than the diamond on the right.

The pavilion of a diamond

The pavilion comprises the bottom part of the gem and is least visible to the viewer when looking at jewellery. The lower girdle facets and pavilion facets serve an important role in redirecting any light entering the diamond back up to the crown. Pavilions that are too shallow or too deep will allow light to escape through the bottom or side of the gem, a phenomenon known as “light leakage”. The culet is the last part of the pavilion and the bottom-most part of the gemstone. Ideally it is not visible to the naked eye in round brilliant cuts, but many older cut diamonds (think old European cuts, mine cuts or rose cuts) have flat culets that can be seen when looking through the table of the gem.

Whether you are looking at a round brilliant diamond, or a fancy shape such as an emerald, oval or pear cut, all three parts of the stone should be examined to ensure that the correct proportions have been met to give you maximum fire, sparkle and brilliance. At Katannuta Diamonds we specialise in Excellent and Very Good cut gems (as certified by the GIA or EGL) so, if you are looking for the perfect diamond in Johannesburg or South Africa, contact us to set an appointment. We’ll share all we know about the anatomy of these beautiful gemstones so that you can make sure you get your perfect piece.

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