While many of the basics of how to buy a diamond apply to all diamond types, they vary a bit among the different colours. Since yellow diamonds are the most commonly known and the most sought after among coloured diamonds, you need to consider some important factors to make a good investment.
How to Choose the Colour of Yellow Diamonds
You already know that colourless diamonds are graded from D to Z on the diamond colour scale. As the letter goes closer to Z, a diamond becomes less colourless and starts to be yellowish in tone. However, at a certain point, if you continue on “the colour scale”, diamond colour stop looking like a faded shade and instead becomes a beautiful yellow colour. This is the point when a diamond is considered to be yellow.
The cause of each diamond colour is different. In terms of yellow diamonds, the reason is the existence of nitrogen molecules which absorb blue light. Depending on the amount of nitrogen, yellow diamonds range from light to dark.
As a part of the fancy colour diamond family, yellow diamonds may also have a secondary hue like orange, brown and green. That is why when GIA (the Gemological Institute of America) grades a coloured diamond it states the exact colour description such as orange-yellow, brown-yellow and green-yellow. Pure yellow diamonds of an intense shade are sometimes referred to as canary diamonds or canary yellow diamonds.
When grading coloured diamonds, besides determining the colour and colour combination, the colour is also graded for intensity.
Yellow diamonds are classified using the following grades: Faint, Very Light, Light, Fancy Light, Fancy Dark, Fancy Deep, Fancy Intense and Fancy Vivid.
In the case of yellow diamonds, there are no Faint, Very Light and Light varieties. Instead, these are referred to as cape diamonds (diamonds from the lower end of D-Z colour scale). The name originates from Cape Province in South Africa.
The first level in which a diamond is considered a fancy diamond is Fancy Light yellow. Among yellow diamonds, vivid yellows are the rarest and most sought after and priced accordingly.
How to Choose the Clarity of Yellow Diamonds
The clarity of yellow diamonds is graded the same way as that of colourless stones.
Yellow diamonds are known to be found in nature with relatively high clarity grade. No wonder that flawless yellow diamonds are more expensive but clarity is not that important because the flaws tend to be less visible due to the stone’s yellow colouring.
Keep in mind that SI1 or SI2 yellow diamonds still appear “eye clean” and do not offer a visible difference compared with diamonds in VS or VVS range. Low clarity yellow diamonds are just as beautiful to the naked eye.
How to Choose the Cut of Yellow Diamonds
The cut quality of yellow diamonds, and all fancy-coloured diamonds in general, is not graded the same way as it is for colourless stones.
Unlike colourless diamonds, fancy coloured diamonds are not cut to maximize brilliance and sparkle. These characteristics are considered to be secondary. Coloured diamonds are cut to maximize colour intensity which results in maximizing their value.
Just keep in mind that an excellent cut yellow diamond costs a premium, so when choosing one it is better to focus on the stone’s hue, saturation and tone and do not judge the diamond using traditional cut grades.
Yellow Diamond Rarity and Prices
Natural coloured diamonds are extremely rare. Only 1 out of 10,000 carats is a natural coloured diamond. However, within the niche of coloured diamonds yellows are the most common. They make up to 60% of all coloured diamonds. So it turns out that approximately 1 out of 16,500 carats mined is a yellow diamond.
When it comes to evaluating the price of a coloured diamond, it requires extreme expertise and it’s quite understandable. When grading yellow diamonds, the first thing you will look at is the colour. Since there are hundreds of colour combinations, the price differences between them are vast. For example, the existence of a brownish tint in a yellow diamond will reduce its price, while green or orange will increase it dramatically. Besides, the stronger the yellow colour, the higher the price.
Fancy Intense yellow diamonds, also known as Canary diamonds, are probably the most sought after yellows. Their yellow shade is very pure and the price is usually 25-50% more than for fancy yellows.
Fancy Vivid yellow diamonds are even rarer and shine like very few diamonds. This makes them twice the price of an Intense Yellow and 3 times the price of a Fancy Yellow. There is a small group of vivid yellow diamonds that are even more valued. These are vivid yellow diamonds that come from Zimmi mine in Sierra Leone.