21 January, 2019

Four Cs of a Diamond - Cut

Diamonds. A fascinating marvel. The fire, sparkle or brilliance - take your pick, they each have their own lure. Did you know that no two diamonds are the same? They come in so many colours, shapes and sizes they each tell their own story.

To help us understand the nature of diamonds and also their quality, GIA invented the Four Cs which consists of Cut, Clarity, Colour and Carat. 

It became universal and now acts as a starting point when assessing a diamond. 

In this guide, you'll learn about 'Cut' which refers to the reflective qualities of a diamond and not its shape!

How Are Diamonds Cut?

So, a diamond is found in its rough form but once it's cleaned, it will then be analysed to see what the best cut is.

The goal? To identify the cut that will produce either the highest quality diamond(s) or the biggest diamond from that rough stone.

Once the decision is made, the rough diamond is marked to indicate the areas which need cutting. These markings will accentuate the potential sparkle and fire of that rough stone. This further illustrates why 'Cut' is the most important component of The Four Cs.

How Are Diamonds Graded?

Here are examples of the grading certifications used to summarise the cut of a diamond.

  • Ideal – Reflects most of the light which enters the diamond. This category applies only to round diamonds (Highest grade for AGS).
  • Excellent - Reflects as much light as an ideal certified diamond (highest grade for GIA).
  • Very Good – Reflects near the same level as ideal/Excellent. These diamonds tend to be bigger in size.
  • Good - Reflects light that enters the diamond but not as much as very good. These diamonds are usually large and would be cut straight from the original rough stone.
  • Fair & Poor – Appears dull or glassy. These diamonds have been cut to maximize the carat weight over most other considerations.

How Does Cut Affect a Diamond?

As you read earlier, the cut will highlight the sparkle and fire of a diamond. It's assessed by shining a light through the diamond to see how light interacts with it.

What you need to know here are three things: Fire, Scintillation and Brilliance. 

  • Brilliance – The total amount of light reflected and refracted in the diamond.
  • Scintillation - Whilst light travels through the diamond's facets and angles, it gives off a sparkle or scintillation.
  • Fire - The transformation of light into different colours such as blue, green and purple. This is called fire and you can see this on the diamond's crown.

To get the most scintillation and fire out of a diamond, aim for a perfect symmetry of both facets and proportion. But, what are the facets of a diamond?

The Different Facets of a Diamond

When you break down a diamond, it contains different aspects:

  • Diameter - The width of the diamond which is measured through the girdle.
  • Girdle - The rim of a diamond that separates the crown and the pavilion. 
  • Culet - The tip of the bottom part of a diamond (pavilion).
  • Depth - From top to bottom, the height of a diamond.
  • Pavilion - Sometimes called the base of a diamond, it's the lower part of a diamond (below the girdle).
  • Table - This is the flat top of a diamond.
  • Crown - The upper part of a cut gemstone (located above the girdle).

Now you know the makeup of the diamond, you can use the image included in this article as a visual aid!

Final Words

Diamonds are truly worth a thousand words.

The way light transforms the diamond is incredible and further strengthens our bond with this beautiful stones.

Now that you have a greater understanding of cut, you can explore further into The Four Cs and become your own diamond expert.

Next up in the series is colour which you can read here: Diamond Guide - Colour.

If you want to explore our certified diamonds then check out our collection here!

Here at William George & Co, you can find jewellery graded by GIA who is an industry-leading authority on Diamonds with nearly 90 years of experience. 

Diamond Guide - Cut