So, you’re in the market to buy a diamond or piece of diamond jewellery, but you’re bewildered by the choices out there and not sure how to tell which diamonds are a cut above the rest or which fall into your budget.

While the quality of diamonds was originally determined by vague terms such as river or water by traders, merchants, and jewellers, that’s all in the past now. Today, everyone considering buying a diamond should be aware of the 4Cs of diamonds —a term coined by Robert M. Shipley, the founder of GIA, the global organisation responsible for the GIA International Diamonds Grading System.

But what exactly are the 4Cs of diamonds, and how do they determine diamond quality? That’s what we’re here for. In this ‘4C’ diamond guide, the expert jewellers at GS Diamonds will take you through the 4 cornerstones of diamond lore and explain just what makes these timeless jewels so valuable and beloved.

What are the 4Cs of Diamonds?

The 4Cs, in the diamond world, are the globally recognised method of assessing any diamond’s quality. But what are those 4 famed Cs, exactly?

They are:

Cut
Clarity
Colour
Carat

These are the driving factors that influence the overall quality and price of the valuable, sparkling gemstones we all love and desire so much. But you don’t have to be a jeweller or a diamond store to know how they work — as a buyer, understanding the 4Cs of diamond quality will allow you to get the best value for your money in your diamond-buying endeavours.

By learning how the 4Cs of diamonds determine the quality of gems, you’ll earn a sliding scale you can use to compare different stones, work out your budget, and eventually choose the diamond most worth your time and money.

How do the 4Cs Determine Diamond Quality?

Let’s move one by one through the 4Cs of diamonds:

1. Cut

The most important of the 4Cs cut gives your stone its ‘wow’ factor: its sparkle. Cut determines your diamond’s ability to handle light — a crucial quality if you’re looking for a diamond that dazzles the eyes. A well-cut diamond directs more light through its crown, while a poorly cut diamond — one that’s too shallow or too deep — allows light to escape through the sides or bottom.

There are a few reasons why cut comes first on the list of 4Cs when buying a diamond:

A properly cut diamond has ‘fire’ – it brilliantly absorbs and reflects light via the top of the stone.
Cut is dynamic — you can combine beauty and value by choosing a lower-carat stone in a superior cut, and it’ll look great.
If you’re looking to get the most value for your budget, focus on the cut before colour and clarity.

GS Diamonds cut grade snapshot: Excellent, Very Good, Good, Fair.

2. Colour

The second most important of the 4Cs is colour, or, rather, a lack thereof. The less colour in your stone, or the ‘whiter’ it appears, the rarer and more valuable the diamond is considered to be. The colour of a diamond generally ranges from a colourless icy white to a light yellow, but the grades in between those two extremes can often be difficult to distinguish.

Here are some general buying tips regarding a diamond’s colour:

After sparkle, colour is usually the second thing you’ll notice about a diamond.
Grade D is considered the most colourless, but you can consider an H or I – if you are price-conscious.
Compare diamonds side by side or get a grading report to identify the colour and value of your diamond.

GS Diamonds colour grade snapshot: D, E-F, G-H, I-J, K-M.

4 C's of Diamonds - Cut, Clarity, Carat and Colour

3. Carat

The next of the 4Cs is the carat. Many people often refer to a diamond’s carat when they want to buy a big diamond. However, carat does not equal size; carat refers to the diamond’s total weight. A diamond may have a high-carat weight without appearing bigger. Two diamonds of the same carat can vary in size depending on the cut of the diamond.

On its own, carat weight is not the sole determining factor of a diamond’s value. However, when combined with the other 4Cs of diamonds discussed in this guide, carat can greatly affect the quality and value of a diamond.

Top buying tips concerning carat:

Diamond prices jump significantly at full- and half-carat weight points (e.g. 1.0ct, 1.5ct, 2.0ct).
Small variations in carat weight aren’t obvious to the eye but can greatly affect the cost.
Always consider carat in tandem with the other 4Cs to determine value and appeal.

GS Diamonds carat range can be anywhere from 0.2 up to 10.0

4. Clarity

The last of the 4Cs is clarity, or flawlessness, of your stone. Bear in mind that most imperfections aren’t visible to the untrained eye. When we talk about high clarity, we refer to the absence of inclusions and blemishes. Diamonds with no inclusions or blemishes under 10x magnification are known to be flawless — and the rarest and most valuable.

Here are our top tips concerning clarity:

Clarity is considered the least important of the 4Cs, as it doesn’t affect the diamond’s visual impact.
Like most things in nature, diamonds are rarely perfect.
The cut of a diamond can go a long way in disguising any natural flaws; consider how the other 4Cs can make up for lack of clarity.
Combine beauty and value: if you look at a diamond and can’t see any flaws without magnification, you can probably choose a lower clarity grade. While an SI clarity grade isn’t necessarily 100% eye-clean, some flaws are hardly noticeable.

GS Diamonds only sell diamonds that are above SI2 grade. This ensures you get diamonds that are clean to the eye.

Embrace the 4Cs of Diamonds with GS Diamonds

Understanding the 4Cs of diamonds is your secret key to making the best decision and getting the best value for your investment. The four pillars of diamond quality — Cut, Clarity, Colour, and Carat — should be considered at all times in the diamond buying process.

GS Diamonds is Australia’s most trusted source for diamonds of exquisite quality and standards. Every diamond in our collection comes with GIA certification that explains the grades of the 4Cs, so you’ll be able to choose the right diamond for you depending on your preferences, whether you’re prioritising Cut, Clarity, Colour, or Carat.

Make your diamond-buying experience a memorable and successful one with GS Diamonds, whether you’re looking to get an engagement ring, a special gift, or individual diamonds.

The 4 Cs of Diamonds: Your Buying Guide