How to look at Coloured gemstones

Coloured gemstones and coloured diamonds don’t depend on the same criteria as white diamonds to sell. While Cut, Clarity and Carat weight are still important, color is the most important. As a general rule, the more intense the colour, the rarer and more valuable the gem.

Let’s have a closer look at each criteria of beauty: Colour, Carat, Cut, Clarity and Origin.


Colour is always going to be top of the list when grading gemstones, as with diamonds. With colored stones, the uniformity, beauty and quality of the colour is a primary determinant of quality and value.

Colour is graded on strength of tone, with a stronger tone commanding a higher price, unless it goes too dark and the value is then severely diminished. Colour can vary sharply depending on the origin of the stone and this in turn affects value.

Colour Swiss Gems Assets Sapphires
Appreciation of colour tones in Blue Sapphires


Bigger stones are consistently considered more valuable than smaller ones. This is true to a point however; if all the other elements are at their maximum, best colour, fantastic cut, exceptional clarity, then smaller stones. 

Carat weight
Price in relation to weight is not linear, the value of a 2 ct is not equal to two times 1 ct.


With coloured gemstones, the complexity of the cut does not affect the beauty in the same way that it will a diamond. Coloured stones have their own natural “glow”, which is only enhanced by the quality and style of the stone’s cut. A simple cut can showcase the high points of a coloured stone just as well as a complex cut. Unlike diamonds, a higher number of facets will not influence the values of the stone. 

Coloured diamonds are affected by cut in a similar way as white diamonds, but still the most important factor of the stone is how it looks. So put the gemstone certificate down and look at the stone!

Classic Cut and Shape in coloured gemstones
Classic shapes and cuts for gemstones


Clarity refers to the stone’s lack of inclusions. Inclusions in coloured gemstones are exceptionally common and only influence the price to a degree. Unless the stone is eye clean, or loupe clean, which can fetch a much higher price, opaque stones will be a lot cheaper.

Generally, clarity is measured with the naked eye, unless looking at very fine natural stones where the inclusions make the difference between a lower price or a higher price.

While emeralds almost always have inclusions, especially larger stones, these do not inherently devalue the stone. If inclusions are generally expected, then included stones becomes the norm and clean stones are out of the ordinary and fetch a premium.

Gemstones Clarity


The origin of a gemstone can greatly affect its value. It is more important in rubies, sapphires and emeralds than in colour diamonds, with the exception of pink Argyle diamonds. The reason price is affected by origin, is that each geographical region gives a stone its own signature look. Burmese Rubies and Sapphires often look quite different to those from Mozambique or Madagascar.

Ruby comes generally from 2 main geographical regions. ASIA: Burma, Thailand, Vietnam, Sri Lanka. AFRICA: Mozambique, Tanzania Madagascar. Burma is most prized.

Sapphire origins follow a similar pattern to rubies, but the most sought after sapphires come from Kashmir, now mostly exhausted, then Burma, Sri Lanka, Madagascar, and other areas such as Thailand, Australia, China, and even Montana. 

For Emeralds, the main origins are: Colombia, Brasil, then Zambia and Afghanistan  supplies very small stones to the market

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