Diamond Basics: A Guide to the 4Cs of Diamonds
DIAMOND GUIDES

Diamond Basics: A Guide to the 4Cs of Diamonds

Learn more about diamonds and the basics of what makes each diamond so unique. Here, our expert gemmologists cover the 4Cs - colour, cost, clarity and cut - as well as budgeting and personalisation, within our detailed diamond guides.
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What are the basics of choosing a diamond?
The value of a diamond is determined by the four characteristics that equate to its beauty and rarity. The fundamental diamond characteristics are known as the 4Cs: cut, colour, clarity and carat weight. These criteria make up a diamond’s grade, with each diamond’s grade being decided on a standardised scale made by the GIA. The higher the diamond grades, the rarer and more valuable the diamond is deemed.
The 4Cs are very important in deciding the grade of diamonds and subsequently how much they are worth. Delve into our detailed guides to explore the 4Cs more closely, see why each of the 4Cs determine how much diamonds cost, and learn how the 4Cs can help you to find the best diamond for your budget.
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The 4Cs

Discover the four characteristics that determine a diamond’s beauty, quality, grade and cost.

What are the 4Cs of choosing a diamond?
When choosing a diamond, you’ll hear a lot about the 4Cs – the four basic characteristics that make up a diamond’s most notable qualities and their overall diamond grade: cut, colour, clarity and carat weight. The higher the grade of each, the higher the value and cost of the diamond. Learn which of 4Cs to prioritise and which to compromise, to find the best diamond for you and your personal budget.

Diamond Cut

When choosing a diamond, the cut is regarded as the most important factor – graded on a scale from 'poor' to 'excellent'. An 'excellent' grade for a cut diamond means the diamond has a bright, icy, inimitable sparkle that only a diamond could possess. Find out more on the importance of a diamond's cut and exactly what makes a diamond sparkle through our rich and detailed diamond cut guide.
Diamond Cut Guide

Diamond Colour

The next most apparent characteristic of a diamond is it’s colour (or, ideally, lack thereof). Some diamonds form with yellow or brownish colour, while others remain colourless. Whilst some people may prefer a coloured diamond, it is usually a coloured gemstone such as sapphires or emeralds that are picked for engagement rings. Compare colour grades with a detailed diamond colour scale, and discover which is the best diamond colour grade for you.
Diamond Colour Guide

Diamond Clarity

A diamond's clarity references the small marks found inside the diamond itself. This is a good characteristic to compromise on if you're looking to save money as most internal marks or inclusions are actually invisible to the naked eye. Therefore, you can prioritise a good diamond grade in cut and colour over clarity. To find out more about the intricacies of the diamond clarity scale and how to make sure you're not wasting money on the highest clarity diamond, see our diamond clarity guide.
Diamond Clarity Guide

Diamond Carat

A measurement of weight, a diamond’s carat correlates to its size. The carat weight of a diamond largely impacts how much it's worth. While many believe bigger to be better when it comes to diamonds, smaller diamonds can be equally stylish and elegant – just take a look at some celebrity engagement rings, like Margot Robbie and Charli XCX's understated rings. Discover what carat weight means, how this affects price and the right carat weight range for you and your personal budget in our diamond carat guide.

Diamond Carat Guide

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4 Cs of Diamonds FAQ

Which of the 4 C's is most important in diamonds?
Cut is generally considered the most important of the 4 C's because it has the greatest impact on a diamond's brilliance and overall appearance. However, the "most important" C is ultimately a matter of personal preference.
What is the best combination of the 4 C’s of diamonds?
There's no single "best" combination, as it depends on individual preferences and budget. However, for maximum visual appeal, many experts recommend prioritizing excellent cut, color in the G-J range, clarity in the VS1-SI1 range, and the highest carat weight your budget allows. This combination typically yields a diamond that appears colorless to the naked eye, has no visible inclusions, displays excellent brilliance, and maximizes size
What is a diamond?
A diamond is crystallized carbon formed under extreme pressure and temperature in a lab or deep within the Earth over billions of years. It ranks as the hardest known substance and valued for its exceptional hardness (10 on the Mohs scale), brilliance, and fire.
How hard are diamonds?
Diamonds are the hardest known substance found on Earth. They are so hard that they rank at the highest hardness level (a 10) on the Mohs scale. Therefore, diamonds are ideal for everyday wear, making them perfect as center gems in jewelry as well as engagement rings.
What are the diamond grades?
Diamonds are graded on a scale developed by the Gemological Institute of America (GIA) that analyzes cut, color, clarity, and carat. These 4 C's are universally acknowledged as the accepted standard in describing and determining the quality of any diamond:
  • Cut: Excellent, Very Good, Good, Fair, Poor (or Ideal, Very Good, Fair, Poor if you have an IGI certificate) 
  • Color: D-Z, with D being colorless and Z showing noticeable yellow or brown tint 
  • Clarity: FL (Flawless), IF (Internally Flawless), VVS1-VVS2 (Very, Very Slightly Included), VS1-VS2 (Very Slightly Included), SI1-SI2 (Slightly Included), I1-I3 (Included) 
  • Carat: Measured by weight, where 1 carat = 0.2 grams