When it comes to diamond education everyone knows about the 4 C’s – cut, color, clarity and carat. 

One point I teach my customers is the spread and proportions of a diamond. Whilst it is important to consider the 4C’s, there is much more to a diamond than what is just on a certificate. The Carat weight measures just the actual weight of the diamond while the spread is determined by the total depth combined with facet angles on the diamond.  

When two diamonds weigh the same ie. 3 carats, this does not mean that face up they will look similar.  Just as no two bodies are the same even if they weigh the same. 

To determine the spread or how large a diamond appears, I always recommend looking at the measurements of the diamond rather than its carat weight. People get too caught up in carat weight and miss the measurements when this is where cost savings can be made. When you purchase a diamond at a specific carat weight you want to ensure it appears to be that size, or larger which will bring you greater value.

However it is super important to consider the proportions , how the diamond was CUT being the most important of the 4C’s to determine sparkle.

We look at a length to width ratios of diamond. Depth is very important, a diamond cut too deep or too shallow can cause light leakage which can can determine the sparkle or dullness of a diamond. In these cases, light travels through the diamond and escapes out the sides, instead of reflecting back through the table to your eyes.

Bottom line is, know the basics but talk to an expert to make sure you are spending your money where it counts and are getting a diamond with fire and brilliance. The grade’s just a starting point, you want to review each diamond individually.


At the end of the day, the performance of a diamond is super important. This means how well the light refracts and in turn the diamond sparkles. Light return and light leakage are what your diamond expert will look for. The result of poor light return or light leakage is a dull or lifeless diamond.


Talk to one of Deltora Diamonds Lab Diamond experts.

(02) 8823 3417 or info@deltoradiamonds.com