Blue Sapphire Grading Guide
In this article we will guide your through how blue sapphires are graded.
WHAT ARE BLUE SAPPHIRES?
Sapphire and rubies are of corundum mineral specie which is an aluminium oxide.
Blue sapphires are a corundum mineral that contain trace elements of titanium and iron which gives them the appearance of blue colour. Blue sapphires are a rare, precious gemstone.
Different minerals belong to different crystal systems based on their way of repeating pattern of atomic arrangement. Corundum belongs to trigonal crystal system.
HOW DO BLUE SAPPHIRE GEMSTONES GET THEIR COLOUR?
Corundum in its purest state is aluminium oxide (Al2O3), which is a colourless sapphire. Additional trace elements or impurities combined with these base elements give breathtaking sapphire colours.
Naturally, a combination of iron and titanium trace elements in the crystal system of aluminium oxide makes a blue sapphire.
Treatments such heat treatment can also alter a colour of a sapphire to blue by simply melting its titanic and iron into the crystals structure. Diffusion and surface coating are synthetic treatment methods and they can also give a sapphire an appearance of blue.
You can shop a range of natural blue sapphire colours in our collection and these are free of any colour enhancements
BLUE SAPPHIRE DURABILITY
Sapphires are the second hardest mineral in the world. That means it is highly resistant to scratches, specially from dust in our environment. Hardness of a blue sapphire being one of the highest also means higher lustre than that of a lower hardness gemstone.
Not only that, sapphires are tougher than diamond. This means sapphires are less prone to chipping and cracking by force such as from knocking or dropping. This is due to its tight bonding of atoms.
Blue sapphires are durable, but not indestructible. Please care to look after such a precious gemstone.
ARE BLUE SAPPHIRES SUITABLE FOR AN ENGAGEMENT RING DURABILITY
Being the most durable blue coloured gemstone, blue sapphires are suitable for daily wear jewellery such as an engagement ring. Blue sapphires are regarded as the most valuable blue coloured gemstone in the world.
WHY ARE BLUE SAPPHIRES SPECIAL?
Blue sapphires are the most popular and well known colour of sapphires.
Renowned for their allure and range of blues; blue sapphires are considered a symbol of love, power, loyalty, royalty and wisdom. Blue is a classic hue that can be worn with an outfit and looks great on everyone.
WHERE ARE BLUE SAPPHIRES MINED?
Blue sapphires are found in Sri Lanka which are known as Ceylon sapphires, Madagascar, Burma, Kashmir, Tanzania, Thailand, Cambodia, Nigeria, China, Vietnam and Australia.
Deliqa Gems carries a collection of the most coveted blue sapphire colours and fine gem quality blue sapphires particularly from Sri Lanka, Madagascar and Tanzania.
HOW ARE BLUE SAPPHIRES GRADED? HOW TO DETERMINE BLUE SAPPHIRE VALUE?
Blue sapphires are not graded the same way as diamonds are graded although similar terms are used for ease of translation of information.
Natural blue sapphires are graded firstly on their colour, then carat weight, clarity and cut.
BLUE SAPPHIRE COLOUR GRADING
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Gianni Versace
Due to sapphire belonging to trigonal crystal system, sapphires are a dichroic gemstone. This means it has two different colours when viewed from the two different sides of the crystal (horizontally and vertically). Blue sapphires generally have a combination of blue-violet, lighter-blue-darker blue, blue-colourless , blue-steel or blue-green.
When a talented gem cutter cuts a blue sapphire, she or he will attempt to place the table or front of the stone in the direction where the sapphire will appear mostly blue while also maximising the yield of the crystal.
Blue sapphires come in different saturations of blue; light blues to mid blues to deep blues with a touch of the secondary hue due to dichroism. So the colour range of a blue sapphires is rather vast!
You have so many blue sapphire options to choose from for your sapphire jewellery!
In naturally coloured unheated blue sapphires, no two will be the same making it incredibly difficult to find pairs. This is why natural unheated sapphires are very much special.
Given that our specialty is natural untreated unheated blue sapphires, you will find a spectacular range of unheated blue sapphires colours in various tones in our range.
WHAT IS THE MOST EXPENSIVE BLUE SAPPHIRE COLOUR AND HOW DOES COLOUR AFFECT BLUE SAPPHIRE VALUE?
Value of the sapphire colour can vary hugely from country to country based on customer preferences.
In mining countries such as Sri Lanka, sometimes the value of a blue sapphire within the local market is much higher than that of elsewhere. This is due to their appreciation and admiration of natural gemstones which they know are rare to find.
Assuming all things same, what is defined as ‘royal blue sapphire’ is currently the most expensive sapphire colour, vastly driven by the demand from customers from China. It is a vivid dark blue colour.
Vividness of the colour is important in defining royal blue sapphire colour. If the sapphire is too dark, the blue colour will not be vivid; the colour will not come out with sparkles. If the sapphire is too dark colour, then the value drops significantly.
In the meantime in Europe, particularly England, Switzerland, Italy, Belgium United States and Canada, customers prefer more vibrant medium blue colour, the typical blue sapphire colour originally became popular from medium blue Ceylon sapphires.
The demand for bright light sky blue sapphires and steel blue sapphires from around the world has increased and hence driven up the value of lighter colour blue sapphires in the recent years.
Preferred secondary hue of a blue sapphire is, violet or colourless.
IMPACT OF BLUE SAPPHIRE WEIGHT ON ITS PRICE
Larger the carat weight, rare the gemstone is. In comparable qualities, higher the carat weight, more expensive the per carat price is. A comparable colour and clarity 2 carat blue sapphire will be more expensive per carat as opposed to a 1 carat gemstone. In comparable qualities, as the carat weight increases, per carat price increase significantly.
BLUE SAPPHIRE CLARITY GRADING
Sapphires are more prone to have inclusions in comparison to diamonds due to the way the crystals are formed. Therefore visibility of sapphire inclusions are graded at eye level, not under a 10x loupe.
Most common inclusions of a blue sapphire are silk, needles, fingerprints, feathers, crystals or cavities.
To put it simply, every single natural gemstone carries some form of natural inclusion, otherwise they will not be a natural gemstones (very likely to be synthetic or even glass). Even a natural diamond that is flawless under 10x magnification would have inclusions that are visible under 20x magnification. Inclusions are important to identify gemstone variety, various treatment methods and to differentiate them from imitates.
Inclusions can vary from location to location. For example, typical Ceylon blue sapphire has needle inclusions whereas typical Madagascan sapphire has bright crystal like inclusions. However, remember “typical” does not mean always.
We have had situations where laboratories have had difficulty in identifying whether the sapphire is natural, synthetic or treated due to being “too clean”. Suspicious sapphires do not make it to our collection at Deliqa Gems under any circumstance.
HOW DOES CLARITY AFFECT BLUE SAPPHIRE VALUE?
Most inclusions do not affect the value of a blue sapphires as long as the inclusions are not prominent, reduce its brightness, or otherwise compromise its beauty.
Inclusions such as needles, crystals, pits along the girdle lines and minor fingerprint type inclusions have little to no impact on a blue sapphire value as they have no impact on beauty or durability.
Some inclusions such as silk can even increase the value of a blue sapphire by giving it a velvety appearance.
Inclusions that may be visible in a light blue sapphire may not be visible in a darker shade of a blue sapphire.
Sometimes “imperfections” are what makes something perfect.
BLUE SAPPHIRE CUT GRADING
While colour, clarity and carat are defined by nature, cut of a blue sapphire is based on human talent.
Blue sapphires cutting grade is not measured the same way as diamonds and it is not necessary to do so. In diamonds, it is only lustre and brightness that need to be achieved where as blue sapphire cutting is much more complicated as we need to pay more attention to colour.
Cut of a blue sapphire is decided based on the shape of the natural rough crystal, placement of colour and placement of inclusions.
Talent of a gem cutter is to decide how to place colour, maintaining maximum weight, reducing the appearance of inclusions and to provide most brilliance. It is a lot of factors to consider and different for each sapphire.
Blue sapphires from different localities requires different knowledge in cutting. For example, a Ceylon blue sapphire cannot be cut the same way as an Australian blue sapphire.
Most of the time from localities such as Sri Lanka, Madagascar, Tanzania, the colour is typically concentrated only in a section of a sapphire. Whereas An Australian sapphire typically has colour spread throughout the entire crystal.
Due to all these factors, majority of natural sapphires simply cannot be cut as per diamond cutting standards.
HOW DOES CUTTING QUALITY AFFECT BLUE SAPPHIRE VALUE?
Symmetrical shapes such as square and round blue sapphires are harder to come across and attract a higher price when it comes to blue sapphires; as it is harder to come across a rough sapphire crystal that can be cut this way.
Assuming all else same, a 1 carat well cut sapphire will attract more than double the price of a poorly cut sapphire. Reason; if the poorly cut sapphire is now well cut, it will certainly weigh much less carat weight. Or alternatively if the well cut sapphire was rather poorly cut, it will have had more carat weight.
At the same time, if not all things the same, quality of the cut does not define the value of a sapphire. Cut can be altered at a later date per-se if the need be but the actual colour and clarity quality of the natural gemstone cannot be. Therefore a larger sized average cut sapphire is more that likely to be the same price as superior cut sapphire. Some prefers average cut sapphires over superior cut sapphires and vs versa. It is a personal choice.
Clean rough blue sapphires are costly and rare. Each sapphire is therefore cut to maximise its colour and carat weight.
It is absolutely important to look at the overall of a natural blue sapphire and not to dismiss a stone based on a single factor.