An Introduction to Blue Diamond Qualities

blue diamond, hope diamond

Ever heard of the Hope Diamond? Due to its exceptional size and the rarity of its colour, this is easily one of the most famous and most coveted jewels in the world. Appraised at almost $250 million USD, the 45.52 carat jewel is currently owned by the Smithsonian Institution. It is graded a fancy dark greyish blue by the Gemological Institute of America Inc.

If you’re searching for a high quality piece, the Hope Diamond is indeed among the rarest of coloured diamonds. Generally, coloured diamonds are much rarer compared to colourless diamonds. Among the coloured diamonds, naturally occurring blue diamonds are the rarest, which is why it comes as no surprise that these stunners are highly valued and sought after.

1. What makes these diamonds blue?

For natural blue diamonds, the colour, which renders the precious stone more expensive and extremely rare, can be attributed to the element known as boron. If during the formation of the diamond, boron is present and its nitrogen content is low, it is likely that the diamond will obtain a bluish hue. A high concentration of boron increases the intensity of the blue colour. In turn, the more saturated the colour, the more valuable the blue diamond becomes.

2. Colour is a top quality determinant.

For fancy coloured diamonds, including blue diamonds, the colour of the gemstone is one of the most important quality determinants. In order to gauge the colour quality of a blue diamond, gemologists will look into three main aspects, specifically the hue, the saturation, and the tone. The colour grade is usually assigned based on saturation and tone.

  1. Hue – This characteristic refers to the visible color that a stone exhibits. For this particular diamond, the primary hue is blue. It can also have secondary hues, which are a different colour. For blue diamonds, green and gray are the commonly found secondary hues.
  2. Saturation – This characteristic looks into the intensity of the colour. A diamond with a pale or faint blue colour is not considered as valuable as a blue diamond with deep and vivid blue hues, which will be more expensive too.
  3. Tone – This characteristic refers to how light or dark the diamond is. The preferred tone level for a coloured diamond is somewhere in the middle – neither too light nor too dark. has an extensive selection of natural fancy coloured diamonds but since natural blue diamonds are very rare, not many jewellery retailers are able to offer these fancy treasures. So it is possible for buyers or investors to come across blue diamonds that are the result of colour enhancements. Generally, white or light blue diamonds are treated to achieve the darker blue colour that in turn increases the diamond’s value.

3. The bigger the carat size, the more expensive it becomes.

blue diamond

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The two most important characteristics when assessing the value of a blue diamond are colour and carat size. Simply put, the bigger the size of the stone, the more you have to pay per carat.

4. Clarity and cut are also considered.

Clarity and cut are of lesser importance for coloured diamonds than they are for colourless diamonds. With regards to clarity, fewer inclusions and external flaws equate to a higher clarity grade, which means a higher value for the blue diamond as well. With regards to the cut, the brilliance and fire of the blue diamond are taken into account.

blue diamond, hope diamond

Image Source: Pexels

Not many jewellers are able to come across this prized gemstone, so if you ever have the opportunity to purchase or even just marvel at the opulence of one, the above are some valuable information regarding blue diamonds.

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