The 4 C’s of Diamonds

When purchasing a diamond there are a number of things that need to be considered. These are more commonly known as the 4′C’s, which are as follows:

Cut – The shape and quality of how the diamond has been cut. This effects the fire and brilliance of the diamond a large amount.

Clarity – When diamonds form, there are always flaws, or inclusions within or on the diamond. The grade of clarity is determined by how many and how obvious these inclusions are.

Colour – The clearest, or ‘white’ diamonds will refract light best, creating the most sparkle.

Carat – The carat is the unit of weight used to measure a diamond. Simply the bigger the diamond, the rarer it is, and therefore the price increases exponentially with size.

For more information about each of the 4 C’s and what needs to be considered when purchasing a diamond, see the posts below.

Diamond Cut

There are 2 meanings to the word ‘cut’ when it comes to diamonds. Firstly there is the shape of the diamond. The most common is a round shape, which is called a brilliant cut diamond. There are many others, from a princess cut (square) to pear shaped cuts, as shown below.


cuts copy

The second meaning is the quality of the cut. This is what is graded when a diamond is certified. This is very important to the quality of diamond. Essentially the cut of the diamond effects the way light enters, travels and reflects back out, and this is what gives a diamond it’s brilliance, or the brightness that radiates from the centre of the stone. The picture below helps demonstrate this.


Good Cut copy


Without going into complicated detail of how a diamond is cut, there is an accepted formulae by experts, for the proportions of a diamond to be cut to in order to maximise the light reflection and brilliance of the diamond.

This can be very complicated and so there is a general grading system for customers to help them determine the quality of cut. This is as follows:

Ideal Cut – The finest cut possible, maximising the brilliance and fire. This category applies only to round cut diamonds.

Premium Cut – Essentially equal to the ideal cut, perhaps with the slightest of differences to the proportions  of the diamond, but never the less, cut to maximise brilliance. They can often be purchased for slightly less than ideal cut diamonds.

You may ask why would anyone cut a diamond any differently than to the proportions of ideal or premium cut diamonds. One answer is to keep price down, the other is to make the diamond bigger, cutting away less will keep the carat weight, but the proportions will differ, effecting the brilliance and fire of the diamond.

Very Good Cut – The proportions are slightly different, which to knowledgeable customers who know exactly what they like and what to look for may be noticeable.  However, on the whole many of the proportions match premium and ideal cuts. These can be purchased for slightly less than premium cuts.

Good – This cut of diamond will still reflect most of the light that enters it, and so there is still good brilliance. This quality of cut is a fair amount cheaper than that of premium cuts, and so if there is a budget to stick to, this is a good cut to make savings, but still have a good quality diamond.

Fair & Poor – These are cut to make the size of the diamond priority, sacrificing the cut quality and therefore drastically reducing the reflection of light.


Diamond Clarity

When we talk about clarity when it comes to diamonds, it refers to the flaws on the surface or within the diamond. When you consider the enormous pressure that a diamond is under when naturally forming, it is no surprise that you will find imperfections.

So what are inclusions. These can range from surface cracks or chips, to air bubbles or non-diamond minerals within the stone. The diamond with less inclusions is rarer, and disrupts the light passing through the diamond much less, and therefore are more expensive.

As with the cut, there is a grading system for the clarity also. The diamonds are graded using a 10x magnification loupe, and it is as follows:

F – This stands for ‘loupe-clean’ flawless. Remember all diamonds will have flaws, but loupe clean means that they are so insignificant that even under 10x magnification, an experienced gemmologist cannot find a flaw. These are incredibly rare.

IF – An internally flawless diamond. These have no visible inclusions within the diamond itself under 10x magnification, but has the slightest of surface flaws. These are also extremely rare.

VVS1 & VVS2 – A very very slightly included diamond. The VVS grade is over 2 grades, VVS1 being slightly better quality than VVS2. These stones have minute inclusions, which are very difficult to detect by a trained gemmologist under a 10x magnification loupe.

VS1 & VS2 – A very slightly included diamond, again over 2 grades. Again with minute inclusions, generally difficult to detect under 10x magnification, although a trained gemmologist will find it easier to find them.

SI1 & SI2 – A slightly included diamond. The inclusions are easily detected under a 10x magnification loupe, but incredibly hard to see with the naked eye by a trained gemmologist.

I1, I2 & I3 – An included diamond. These inclusions are easily spotted under 10x magnification, and more than likely seen with the naked eye also. If a diamond falls in this category, the price will be significantly less. This category of diamond can also be referred to as a pique diamond, or P1,P2 & P3.

Below is a general chart of what each grade may look like under a 10x magnification loupe.


 clarity copy


It is important to remember that although inclusions lower the grade, they are a way of proving the diamond is genuine, and as no 2 diamonds are the same, also give the diamond its identity, just like a finger print.

When purchasing a diamond, especially when there is a budget involved, it is important to remember that the clarity is graded under the 10x magnification. To the naked eye, anything from SI1 cannot be seen, so with the budget in mind, it may not be worth, for example, buying a VVS grade diamond, when the difference will more than likely be unnoticeable to a VS grade diamond.

Even SI grade diamonds that are ‘eye clean’, meaning you cannot see inclusions with the naked eye are considered a nice diamond, and great for cost cutting, especially when you still have the other 3 C’s yet to consider.

Diamond Colour

When we think of a diamond we generally always think of a perfect white sparkling diamond. It may sound strange, but very rarely is a diamond truly white or ‘colourless’. Many diamonds will have a hint of yellow in them, and therefore there is a white-yellow grading system. This system does not work for fancy diamonds, which can be any colour, from blue to pink, and are in fact generally more expensive due to their rarity.

A colourless diamond, just like a clear window, will always let more light pass through, and therefore create a better sparkle and more fire. Truly white diamonds are very rare. It is important to remember the composition of the diamond is what gives it its colour, or non colour, and so the colour of a diamond will never change.

The grading scale starts at D, with this being the whitest, through to Z as shown below.


 colour 2 copy


D-F grade diamonds are the rarest and most beautiful, however any diamond from G-I are still considered extremely beautiful stones. It would probably take a stone from J-L for an untrained eye to actually notice a hint of yellow, and you would probably still need a comparison stone to actually see the difference.

Once you get to M and above, the hint of yellow becomes more apparent, but when there is a budget involved this is a way to save money. Some people actually like the character of a yellow tinted diamond.

So what colour stone should you buy? This depends on your budget, and whether the colour is more important to to you than say the size, cut or clarity. What is important to remember is that the difference between 2 or 3 colour grades is minimal, and practically undetectable to the naked eye, so this is a way to save some of the budget.

Diamond Carat Weight

The carat weight is simply the unit of measurement for the weight of a diamond. One carat is equal to 0.2g.

Do not confuse carat weight of a diamond with karat, used for determining the purity of gold.

Larger diamonds are rare, and therefore more desirable and more expensive. The price of a diamond will increase exponentially with its weight.

Notice that I say weight and not size. Whilst size will obviously increase with weight, the actual diameter of the diamond can be effected by the quality of cut of the stone. If you have 2 diamonds of equal weight, their diameters can still be different. If a diamond is cut too deep, the diameter of the stone will be less, and if cut too shallow it will make a larger diameter, and both will negatively effect the brilliance of the stone. This said, the carat weight of a well cut stone will generally translate to the sizes shown below.


carat 4


Deciding on the size of diamond you want to buy depends on a number of things. Firstly the budget. Secondly what is more important to you, the size or the quality? Is it more important to you to get a diamond with a better colour and clarity grading than a large diamond?

Other things to consider is the finger size of the person wearing it. Small fingers will make a stone look proportionally bigger. There is also the setting of the diamond. Make sure that the setting matches the carat of the diamond.


Precious Metals

In the jewellery industry there are a number of precious metals that you will have to chose from. This post will describe the properites of each one.


Gold comes in yellow and white gold, and apart from their appearance, they have the same properties. Gold in its purest form, being 24 karat, is a soft and ductile metal with a high lustre. When purchasing gold items, you will often come across different karats of gold, which each have a different hallmark, which I will cover in another post.

9ct Gold – This is the least valuable form of gold you will find, as it is the least pure, having been mixed with other metals to reduce its purity. The main reason this is done is to bring the price down. 9ct gold will have less lustre, it will not be such a bright yellow, but it will be a harder metal than higher karat gold, due to the other materials mixed with it are harder than pure gold.

14ct Gold – This is not as common in the UK as 9ct and 18ct gold, but is found in Europe a lot, and so it is likely you will find it from time to time in the UK. Essentially, it will have a higher lustre, will be slightly softer and more expensive than 9ct gold.

18ct Gold – This is the highest purity of gold found in the UK and Europe, and what is generally what is used for expensive jewellery pieces such as wedding and engagement rings. 18ct gold has a high lustre and much softer than 9ct gold.

22ct Gold – This is most commonly used in India, and is the highest purity of gold you are likely to come across. It is very soft and has a very high lustre, and is very expensive.

As mentioned above, you also get white gold. The thing to remember is all gold is yellow. What makes it white is the white materials mixed with it to reduce its purity. 18ct gold is the highest form you will find white gold in.

White gold always has a yellow tint to it, because of the natural gold colour. To make it a bright shiny white, it is rhodium plated. There is a bit of maintenance involved with white gold, as the rhodium will fade, and so you will need to re-rhodium it, typically once a year. If you wish to prolong the life of the rhodium plate, take the ring off when doing things like washing up, cleaning or swimming.


Silver is the cheapest of the precious metals, and the recognised standard is sterling silver.  Like gold it has a high lustre and is fairly soft, but is more common. You will often find silver is used for items with semi precious stones, not for diamond pieces. Silver, if left alone for a while will tarnish. This is easily remedied, simply placing it is silver cleaner, which is available in any jewellers, for 30 seconds will clean it so it looks like new.


Platinum is the rarest and most expensive precious metal used in jewellery. It is a white metal with high lustre, and is also a very hard and durable metal. Unlike white gold, it is naturally white, and so there is no rhodium plating or maintenance required.


This is a relatively new precious metal, and is actually part of the platinum family. It is therefore a naturally white metal, and again very hard and durable. However it is much cheaper than platinum, falling between the 9ct gold to 18ct gold price range.


Aside from the properties of the metals, there are a few things to consider when purchasing them. Firstly there is the maintenance. I have already mentioned white gold, but there are things such as repairs to think about. Although platinum is a very hard metal and so less likely to break, if it does need to be repaired, it will be expensive. 18ct gold is soft but also expensive, although not so much as platinum, but due to its softness it is more likely to need repairs.

One other thing is that when you have two items sat next to each other, such as a wedding ring and an engagement ring, or a chain and pendant, make sure the metals are the same. If you have a 9ct ring next to an 18ct ring, the 9ct ring being harder will wear down the 18ct ring.


All items of jewellery should have hallmarks on them. They are one of a few ways to prove that they are genuine pieces. Likely hallmarks you will find on jewellery could be telling you what the type of metal is, the assay office where it was stamped, the year it was made, or a makers mark.

In terms of what the metal type is, this hallmark is a number, which actually tells you how pure the metal is. The shape of the hallmark will also tell you what metal is. These hallmarks are as follows.



9ct gold hallmark copyThis is the hallmark number for 9ct gold, with a hexagon shape to show that it is gold. The 375 relates to how many parts per thousand is gold. So 9ct gold is made up of 375 parts of gold per thousand, the rest being other base metals.


14ct gold hallmark copyThis is the hallmark number for 14ct gold, with a hexagon shape to show that it is gold and with 585 parts of gold per thousand.



18ct gold hallmark copyThis is the hallmark for 18ct gold, with a hexagon shape to show that it is gold and with 750 parts of gold per thousand.



22ct gold hallmark copyThis is the hallmark for 22ct gold, with a hexagon shape to show that it is gold and with 916 parts of gold per thousand.



Although no jewellery is ever made from 24ct (pure) gold this is actually 999 parts of gold per thousand.



Silver can be found with a number of hallmarks, it will either be a number or a lion as shown bellow:

silver hallmark copyThis is the hallmark for sterling silver, with 925 parts of silver per thousand, with an ellipse showing that is silver. Sterling silver is the modern day standard for silver.


silver lion hallmark copy

This is also commonly used as a hallmark for silver.


You may also come acrossBritannia silver, which is found on older pieces, like silver cups and ornaments. Britannia silver is actually slightly more pure than sterling silver, with 958 parts of silver per thousand with an ellipse showing that is silver.


Platinum & Palladium


platinum1 hallmark copyThe hallmark for platinum can either be 900, 950 or 999 dependant on its purity. The ‘house’ shape shows that is is platinum.



platinum hallmark copy




palladium hallmark copyRather confusingly 950 is also the number for palladium. It is the circles that show that it is palladium.