Diamond Education

When buying a diamond ring you should be conscious of a few basic points regarding how diamonds are valued. In just a few minutes you'll know everything you need to know to find your perfect diamond. The value of a diamond is determined by its quality and individual characteristics.

Buying a diamond does not have to be an uncomfortable experience. David East Jewellery Online diamond education guide is designed to assist you in answering all your questions and educating you to properly evaluate diamond quality and its value, making your confident diamond purchase as easy and stress free as possible.

Every diamond is unique, and there are a variety of factors which affect the price of a diamond. Focus on those factors most important to you, and choose a diamond that satisfies your individual standards for beauty and value. This might be a very different diamond than someone else with a similar budget would choose.

Ensure that your diamond comes with a certificate from an internationally recognized laboratory. At David East Jewellery Online we will provide a diamond certificate from a reputable and reliable laboratory like the GIA, AGS, IGL, EGL and Auscert that corresponds to the diamond which ensures you get exactly what you have paid for. You can be 100% confident that the stones provided by us are exactly what we say that they are.

The 4C’s

The properties of a diamond are measured using the 4Cs. That is Cut, Clarity, Colour and Carat. A diamond's cut indicates its shape and how well the diamond has been cut to that shape. Clarity is the measure of a diamond's purity and how many flaws it has. A diamond's colour refers to how yellow it looks. The most expensive diamonds are clear while the less expensive have a yellowish appearance. Finally, a diamond's carat measures its weight. One carat is 200 milligrams and there are 100 points to a carat. When comparing rings you like of similar price you may wish to ask about the diamond's 4C properties as it can provide you with a guide to which ring offers best value.


A diamonds cut is undeniably the most important of the 4 C’s. Even with close to perfect colour, size and clarity if a diamonds cut is not in correct proportions all other characteristics will not be as highly valued. The way in which a diamond is cut will determine how the diamond reflects light and hence determine its brilliance or sparkle. A poorly cut diamond will appear lifeless and dull.

When light strikes a diamond, approximately 20% immediately reflects off the surface as glare. Of the 80% that enters, a portion will escape through the bottom of the diamond where the observer cannot appreciate it. A well proportioned diamond will have each facet properly placed and angled, which will maximize the amount of light that reflects back out of the crown or top of the diamond, to the eye of the observer. This reflected light is called the brilliance of the diamond.

Diamonds reflect their light from one facet to the other. If the cut of the diamond is too deep then light will escape through the opposite side of the pavilion or bottom of the diamond. On the other hand if the cut is too shallow then light will escape through the pavilion before it can be reflected. 

Diamonds can carry cut grades of Excellent, Ideal, Very Good, Good, or Fair.

Excellent; Representing roughly the top 1% of diamond quality based on cut. The highest grades of polish and symmetry allow it to reflect even more light than the standard ideal cut.

Ideal; A diamond described as Ideal represents the highest standards of cut, with only the top 3% of all diamonds falling in this category. An Ideal Cut diamond reflects nearly all the light that enters it and displays maximum brilliance and fire. For those who want the very best that money can buy, this is the cut to choose.

Very Good; A diamond described as Very Good reflects nearly as much light as an Ideal cut diamond, and represents approximately the top 15% of diamonds based on cut. The proportions may overlap with many of the proportions of an Ideal cut, with slight variations from the preferred range that allow the cutter to create a larger stone. A diamond with a Very Good cut has exceptional brilliance and is generally priced slightly lower than an Ideal cut diamond.

Good; A diamond described as Good reflects most of the light that enters it, and is much less expensive than a Very Good cut. A diamond in this category represents roughly the top 25% of diamonds based on cut. Its proportions may vary from the preferred range because the cutter has opted to maximize the size of the stone rather than creating a smaller Very Good quality diamond. For those shopping on a budget, a diamond in this range offers good quality and excellent value.

Fair; A diamond described as Fair represents the top 35% of diamonds based on cut. Though it is still a quality cut, it reflects less light and displays less brilliance than a Good Cut diamond. Diamonds in this range are typically cut to maximize size over their factors.Amazon.co.uk: Diagram explaining diamond cut

Shape; The traditional round cut provides a combination of the best qualities a diamond can have. The symmetry of this shape means it is capable of reflecting nearly all of the light that enters it and it therefore has the greatest potential for a diamond’s hue and brilliance. There are also other shapes that can emphasize a diamond's different features. The choice of a shape is best based on personal taste and the design of the jewellery.


The most desirable diamonds are those which have the least amount of colour. The less body colour in a white diamond, the more true color it will reflect, and thus the greater its value. Quite often however diamonds will have a presence of a yellow or brown tint which will lower the price the diamond. 

Of the 4 C’s colour can be the most confusing to understand. It’s not until you get to the I-J range and onwards that you start noticing hints of colour and even so it depends on how you are viewing the diamond.

The photo below shows a master set used by gemologists to colour grade the diamonds. When viewed face up the diamond will appear perfectly white however when viewed face down against a completely white background you will be able to detect the colour much more easily. The colours you see below have a large colour grade of separation of D, K and Z of the master set. Every diamond is to be colour graded and compared to the master set to determine where it should fall on the diamond color scale.

Diamonds of D, K, and Z GIA Grading Masters

Another element to consider that affects a diamonds colour is the setting and the colour of the metal used when mounted into the ring. Yellow gold makes slight amounts of yellow in a diamond less obvious, while white metal settings or mounts make the colour in yellow diamonds more apparent.

The price difference between the various colour grades can be significant so to help you make the right choice you should really find out which of the diamonds characteristics or the 4 C’s are most valued by your partner. Near colourless diamonds are more common and offer great value for money.


All diamonds contain birthmarks or small imperfections inside the diamond that are called inclusions. The imperfections found on its surface are called blemishes.

Clarity simply refers to the degree to which the tiny imperfections are present within the diamond. Diamonds that contain numerous or significant amount of inclusions or blemishes have less brilliance because the flaw’s interferes with the lights pathway through the diamond.

The clarity of a diamond is what ultimately makes it unique as no two diamonds have the same markings or inclusions in the same area. Diamonds with the least and smallest imperfections receive the highest clarity grades. Because these imperfections tend to be microscopic, they do not generally affect a diamond's beauty in any visible way. For example a diamond which has no inclusions is rare and will be reflected in the price.

The clarity grade is determined by several factors including;

The size of the inclusion in the diamond

How many inclusions are in the diamond

The positioning of the inclusions - inclusions found under the table can affect clarity grade more so than inclusions found under the side facets

The visibility of the inclusions - the darker the inclusions the less favourably the grade will be

When purchasing your diamond you should consider the colour and clarity together. A diamond graded D-F would be best if it had a clarity grade of VS2 or higher whereas a diamond in the G-I range is well suited to clarity grades of SI.

A diamond categorized as internally flawless will have no inclusions, but this is extremely rare. Diamonds with very, very small inclusions are graded as VVS1 or VVS2. Those with larger inclusions appear lower down the grading skill. Diamonds with inclusions that are visible with the naked eye are graded P1/I1 to P3/I3.

The degree of inclusions and the universal method of calculating a diamond’s clarity can be seen in the diagram below. Most inclusions are not visible to the naked eye however under 10 x Magnification, they become apparent.


Carat’s is the actual unit of weight for diamonds, though most people think of a carat in terms of size. Carat weight, by itself may not accurately reflect a diamond's size. A carat is equal to 100 points and exactly 0.2 grams. Carat weight of a diamond is also not related to the similar sounding karat of the gold’s purity term.

The higher the carat weight the more valuable and rare the diamond. It is worth noting that a 2ct diamond will be more valuable than two 1ct diamonds as finding larger rough diamonds is not as common. Two diamonds of equal carat weight can have very different costs based on other factors that maybe; cut, color, clarity and also fluorescence.

To gain an exact understanding of a diamonds size we recommend considering the carat weight with two other characteristics that will guide you. 1) The total width of the diamond in millimeters and 2) The diamond's cut grade.

It is important to measure the distance across the top of the diamond as this is how we view a stone when set into a ring. 

The cut grade of a diamond should also be considered because, as we mentioned in the cut grade section, when a diamond is cut with the ideal proportions, the maximum amount of light is returned out of the table or top of the diamond that creates the brilliance and life of the diamond. For example if you had a 1ct diamond which was ideal cut that was proportionate where as if you had a poorly cut 1ct diamond it may be heavier on the bottom and have a narrow diameter that wouldn’t reflect the light back through the table resulting in a lifeless diamond.

It is therefore possible to have a diamond of a lower carat weight, but higher cut grade that appears larger than a diamond with a larger carat weight, but poor cut.

Once you've selected your cut, color, and clarity grade, it's easy to determine the carat weight of diamond that will fit within your budget.

What Carat Weight Is Right For Me?

Choosing the best carat weight of diamond you have to consider the size of your finger, the size of your setting and your budget that you would like to spend.

If a larger carat weight is important to you and you’re working to fit within a strict budget you consider a diamond with a good cut, SI1-S12 in clarity and a G- I in colour grade. If the size still didn’t fit your budget, work on a sliding scale with the clarity and colour grade to find your perfect diamond.

Diamond prices jump at the half carat or 50 points and the 1 carat weights. Diamonds just below these weights cost considerably less.

Keep in mind that a smaller finger will make a 1 carat diamond look bigger then a 1 carat diamond on a larger finger size.

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