Everything You Need To Know About Loose Cognac Coloured Diamonds
Let’s firstly clarify what a cognac colour is…
It’s a very deep brown, typically with a secondary tone of yellow. The tonal combination evokes thoughts of a fine cognac whiskey, chocolate, and cinnamon in a range of hues and saturation.
There are several causes for the brown colour, including irradiation treatment, nickel impurities and lattice defects associated with plastic deformation; the last is the predominant cause, especially in pure diamonds. A high-pressure high-temperature treatment can heal lattice defects and convert brown diamonds into yellow or even colourless stones.
What Are Argyle Cognac Diamonds?
Argyle Cognac Diamonds
The majority of cognac diamonds are unearthed from the Argyle Diamond Mine in the East Kimberley region of Western Australia. The Argyle Mine is responsible for producing a large percentage of the world’s coloured stones, including their signature red diamonds.
Grading Cognac Diamonds Colour
You will never see the word “cognac” on a grading report from the Gemological Institute of America. Instead, the colour would be described as fancy deep yellow brown, fancy dark yellowish brown, or a similar phrase that indicates the hue and intensity.
On the other hand, The Argyle Mine has devised a different colour scale specifically to grade cognac diamonds, which ranges from C1 to C7. C1 is the lighter (champagne) end of saturation with C7 being the darkest.
+ How Rare Are They?
Natural cognac diamonds are quite abundant but can be difficult to find in fine cut qualities & light performance with a visual pleasing tonal range of colour (due to the mix of brown and yellow colouration).
+ Are They Expensive?
Now while it can be difficult to find options you would consider for selection, they are quite cost effective due to their more common rarity and market-demand factors.
+ Are There Alternate Gemstones You Can Recommend?
Due to the cost effectiveness of this naturally coloured diamond, it would certainly be the best choice for and engagement ring, wedding ring, or any piece of jewellery that was worn regularly. For more occasional pieces we would recommend considering Natural Zircon, Brown Tourmaline, as well as Brown Mali Garnet.