Avita are proud of their reputation as industry experts, drawing on generations of experience to craft and create the perfect diamond ring or jewellery for you.

It is an important decision you are about to make and we want to help you in every way we can.

Here is our guide to everything diamonds.

The Four C’s

This is the basis of how diamonds are judged, based on:

  • Cut
  • Carat
  • Clarity
  • Colour


We would also add two further C’s, being

  • Certification and
  • Conflict-free diamonds.


The diamond cut affects how brilliant the stone is. This isn’t about shape (whether it’s pear or oval) but is dependent on the original shape of the rough stone. There will be flaws to be smoothed away without reducing its weight and maximising its appearance. Shape often changes depending on fashion and trends but cut is timeless. A well cut diamond reflects the light beautifully and gives it that famous sparkle.

diamond facets

The Importance of Cut Quality

The key to a diamond cut is to reflect light. With a high quality cut the light enters the diamond through the table and crown - it travels towards the pavilion and then reflects from one side to the other. Finally it bounces back from the diamond’s table to the observer’s eye. This is called “light return” and it affects the diamond’s brightness, brilliance and dispersion. Poor symmetry or a poor cut will cause light-leakage and will adversely affect the quality of light return.

Below are examples of the “Shallow Cut” and “Deep Cut” showing how light enters through the table of a Modern Round Brilliant diamond, reaching the pavilion facets and then leaking out from the sides or the bottom of the diamond rather than reflecting back to the eye.

deep cut diamond

Simply put, less light means less brilliance.

In the “Ideal Cut” most of the light entering the diamond through the table is reflected back to the observer from the pavilion facets.

ideal cut diamond

What to remember….

  • Cut isn’t about shape.
  • How well a diamond is cut determines how brilliant your diamond will look.
  • If you’re looking for sparkle go for a Very Good or Excellent Cut.


The carat of a diamond is a measurement of both its size and weight.

One carat is around 0.2 grams.

A carat can also be divided into points with one carat being equal to 100 points. Therefore, a 1/2 carat diamond would be 50 points, a 3/4 carat diamond is 75 points, and a 2 carat diamond is 200 points. Below is a table giving you the approximate diameter of four round brilliant cut and princess cut diamond sizes;

Round Diamond

Carat Diameter
0.30ct 4.50mm
0.50ct 5.50mm
0.70ct 6.00mm
1.00ct 6.50mm


Princess Cut Diamond

Carat Width
0.30ct 3.50mm
0.50ct 4.50mm
0.70ct 5.00mm
1.00ct 5.50mm

The above is for guidance only.

What to remember …

  • Carat measures both size and weight
  • Carat will help you judge the size of stone you want in your diamond jewellery or ring


Clarity means the absence of imperfections in your diamond, both within it and on the surface. There is a grading system to help you understand how clarity is ranked.

IF Clarity - "Internally Flawless" no inclusions at 10 x mag. - small blemishes

internally flawless

VVS Clarity - "Very Very Small" inclusions hard to very difficult see at 10 x  magnification

vvs clarity diamond

VS Clarity - "Very Small" hard to see inclusions only visible at 10 x magnification. - Clean to the human eye

VS clarity diamond

SI-1 - "Small" or "Slight" Inclusions not visible to the human eye. Visible under 10 x magnification.

SI clarity diamond
I1 to I3 - Imperfect, with large Inclusions, fractures, and flaws - Not sold by Avita

We always choose diamonds SI clarity or above. From this grade and above you should not see any inclusions with the naked eye.



The images above explain the GIA grading system for inclusions and imperfections. Considerations in grading the clarity of a diamond include the type of stone, point size and the location of inclusions. Inclusions that are near to, or break the surface, may weaken the diamond structurally, therefore reducing its value significantly. On the other hand, it may be possible to hide certain inclusions behind the setting of the diamond (depending on where the inclusion is located), thus minimizing any negative impact of the inclusion.

Avita work with diamond from Internally Flawless (IF) to diamond with slight inclusions (SI2). With Avita diamonds you should never see an inclusion with an untrained eye.

What to remember …

  • Clarity means measuring natural imperfections in your diamond
  • The grading system helps you to judge the clarity of the diamond you’re choosing


Here’s the science bit. The colour of a diamond is affected by the nitrogen atoms within it.

Most natural diamonds contain small quantities of nitrogen atoms that displace carbon atoms within the crystal’s lattice structure. They are evenly dispersed through the stone and absorb some of the blue spectrum. This is why the diamond appear yellow. The higher the amount of nitrogen atoms, the yellower the stone will look.

The colour rating of a diamond is judged by a chart first defined by the Gemological Institute of America(GIA). It runs from “D” to “Z” with “D” being “Pure White” and “Z” “yellow”.

The colour chart explains the GIA grading system for diamonds.


D, E, F -  Rare white

   D colour DiamondE Colour DiamondF colour diamond

G, H -  White

  G colour diamondH colour diamond
What to remember …

  • The less colour a diamond has the more valuable it is
  • Avita only uses diamonds graded between D-H so we only work with the top grade of diamonds.


At Avita we will work with the top diamond grading laboratories of the world. All our diamonds over 0.30ct are graded by either GIA, IGI, HRD and other leading diamond grading laboratories from around the world.

If you have a preference on a particular certificate then please Contact Us to let us know and we will happily make your jewellery with your specifications.


Avita takes steps to ensure its diamonds have not come from conflict zones. We ask and inspect all our suppliers to make sure they do not handle conflict diamonds and that they have subscribed to the Kimberly process thus eliminating conflict diamonds.

Avita Jewellery will never sell or handle diamonds without having guarantees the diamond is conflict free.

And finally…

All this information maybe a lot to take in. Don’t worry - take your time and very importantly, trust who you buy from.