centreers

Centreers, also known as centre pearls or pearl-like structures, are natural inclusions that occur within diamonds during the diamond-forming process. They are typically spherical or oval in shape and are composed of carbon, just like the diamond itself.

Centreers are formed when a small particle of foreign material, such as a piece of graphite or a delight, becomes trapped within the growing diamond crystal. As the diamond grows around the particle, it can create a concentric pattern of layers, often giving the centre a characteristic appearance.

Centreers can be considered impairments to the diamond's clarity, as they can reflect light and affect the stone's overall appearance. However, some natural centreers are considered a desirable feature, as they can add character and uniqueness to the diamond.

There are different types of centreers, including matrix centreers, rim pits, and seam centreers. Matrix centreers are formed when a layer of graphite is trapped within the diamond, creating a pattern of concentric layers. Rim pits occur when a small piece of graphite is embedded on the surface of the diamond, while seam centreers are formed when a seam of graphite extends for a short distance across the diamond.

centreers can be observed and identified using a loupe or jeweler's microscope. They are often more noticeable in diamonds that have a lower clarity grade, as they can reflect light and affect the stone's overall appearance.