Diamondcode.com.au Blog

Your Guide to Coloured Diamonds

Posted in: Diamonds | Posted on: Mon, 30 Mar 2020

Diamond classification is a massive part of diamond sales, with cut, colour, clarity, and carat weight all helping to establish the price tag and desirability of any diamond. But when you’re referring to colour, it’s easy to assume that you’re talking about the colour purity of a white diamond, and nothing else. Did you know that coloured diamonds like red, blue, pink, and green diamonds also exist? 


Whether you’re looking for that unique piece to add to your jewellery box, about to get married, or looking to invest in fancy coloured diamonds, read on. Here is everything you need to know about coloured diamonds. 


When we talk about diamonds, we usually think of them as being white. But there is perfection in imperfection, especially when impurities in the world of diamonds occur. All of a sudden, that perfect white diamond has been affected by a natural process that causes a colour change. And that’s how blue, pink, green, and red diamonds come to exist. It’s not a dye added by a jewellery expert. It’s deformation with a surprising and uniquely beautiful result. 

Blue diamonds get their colouring from boron, while brown diamonds are deformation and yellow diamonds have an abundance of nitrogen. Other minerals and natural processes can even result in black, purple, green, and pink diamonds. 

When that happens, you no longer grade the diamond using the standard GIA classification. Standard white diamonds will be graded on their colouring from white to light yellow, but coloured diamonds are judged on their hue, tone and saturation. 


Being so used to seeing white diamonds, it can be hard to wrap your head around the existence of a pink, blue or even red diamond. 

If you stumble across a brown, blue, or yellow diamond, then light absorption is the cause. The change of colour can be as simple as trace elements in the diamond absorbing light and reflecting that light as a colour, rather than white as you might expect. 

Light absorption also plays a part in the creation of pink or red diamonds. Deformities in the structure of the crystal cause that light absorption, but only the red component reflects to create that pinkish hue. 

green diamond is formed differently. As the crystal is forming, irradiation occurs to cause that colouring. We’ll get into more detail on these processes below. 


There’s something truly spectacular about a blue diamond ring, and it’s not necessarily just the colour that captures your attention. Unlike all other diamonds, the blue variety is the only one that can conduct electricity, and we think that’s pretty special. 

The diamond gets its colouring from the presence of boron, but the shade of blue can differ. Some blue diamond rings are more blue-green or blue-grey, while others have a subtle blue hue. 


There is a difference between a white diamond with hints of yellow and a yellow diamond. A white diamond with hints of yellow will be of a lower grade, but a pure yellow diamond has a different makeup. Nitrogen is responsible for the colouring of a yellow diamond. 


Both red and pink diamonds are rare, and they are not variations of each other, but rather their own defined category. Red diamonds are the most expensive, and there have been very few ever to exist. They are formed through extreme pressure causing a shift in the crystal while it’s developing. 

Pink diamonds are a little more common but are by no means your standard, everyday diamond. They are formed under the same conditions as the red diamond. 


As previously mentioned, irradiation is responsible for a green diamond. There are pockets of radiation in the earth, and if a diamond happens to be growing nearby, it will take on a green hue. 

Green diamonds are so rare, however, that they are often more of a collector’s piece than something you would buy as part of jewellery. It’s not uncommon for the price tag to be upward of $3 million per carat. 


Purple diamonds are beautiful, but are certainly an example of “perfection in imperfection”. They are formed similarly to red and pink diamonds, but with a higher presence of hydrogen to offer different shades of purple. The crystal often tends to be quite deformed, but that doesn’t stop them from looking breathtaking in the right setting. 


The diamond you choose can all come down to your preference and budget. Some people prefer the cleanliness and elegance of a white diamond, but others are more inclined to stand out from the crowd with a coloured diamond. 

Although we don’t sell coloured diamonds on diamondcode.com.au, you can browse and enquire about them on our sister website, diamonds.co.nz. Why not check out what we have to offer and see what speaks to you?