Be it as part of stunning jewellery or a standalone purchase, precious and semi-precious stones are considered by many as an investment. Ranging in size and appearance, the precious stones – diamonds, emeralds, sapphires and rubies – are assets that don’t lose their value with time. Moreover, as the mines of precious stones are being exploited more and more, the value of decent sized natural precious stones will continue to grow.
There are certain criteria that determine the price of clear and coloured precious stones. One can spend a lifetime learning all aspects of the pricing and evaluation of precious stones. But, unless you have completed a gemologist’s course and committed your life to this trade, there is a good chance that you might have a few questions when choosing for your next jewellery.
We spoke to Nadine Aysoy, the certified Gemologist and luxury 18K gold jewellery designer, working with precious and semi-precious stones. In this article, Nadine shares her expertise on Sapphires, precious stones that are prominently featured in her jewellery.
Sapphire gemstones are a form of the mineral Corundum. If Corundum is Red, it is called Ruby, any other colour of Corundum is called Sapphire. Trace amounts of iron and titanium can develop a blue colour in corundum. It is one of the hardest gemstones on earth, with only Diamond being harder. Contrary to popular belief, Sapphire gemstones are not just blue. They can be Blue, Green, Yellow, Orange, Pink, Colourless or any combination of these colours. “Pink sapphires represent my favorite colour of this popular gemstone,” commented Nadine Aysoy. She continued, “they are found in limited regions of the world such as Madagascar and - recently - Sri Lanka and Myanmar.” Pink sapphires symbolize loyalty, trust, and sincerity, and are sometimes referred as the gems of truth with healing benefits making them popular stones for engagement rings.
One of the rarest and most sought after Sapphire gemstones is called Padparadscha. It is a beautiful pink orange stone.
There are no standardized cuts for sapphires as there are with diamonds. Whereas with diamonds you could choose an “ideal” cut to showcase the diamond’s colour and fire, with sapphires — and most coloured gemstones — you are relying on the gem cutter to maximize each individual sapphire’s unique combination of colour, clarity, and brilliance.
“In general, a well-cut sapphire will be symmetrical and reflect light at the proper angles in order to enhance the stone’s luster. You can see that in all Nadien Aysoy jewellery. They too, like diamonds, will be graded either excellent, very good, good, fair, or poor.
Most sapphires will come with a few inclusions. Sapphires with no inclusions should cast suspicion as there is high probability they are synthetic. You want to look for a sapphire that has no inclusions visible to the naked eye. experts look at the size, location and number of inclusions to judge clarity. The less visible the inclusions are, the higher the grade.
Since sapphires are usually heavier, a one carat sapphire will look smaller than a one carat diamond. It is more accurate to measure the size of the sapphire in terms of its millimetre diameter. A rule of thumb is that a one carat sapphire generally measures 6 mm. Blue sapphires can range in size anywhere from a few points to hundreds of carats, and large blue sapphires are more readily available than large rubies. However, most commercial-quality blue sapphires weigh less than 5.00 carats.
Large commercial-quality blue sapphires are more common than large fine-quality ones. As a result, size makes more of a difference in the price of fine-quality sapphire. A fine-quality 5.00 carat blue sapphire sells for approximately five times more per carat than the same-quality 1.00 carat stone.
Colour or Saturation
While diamonds have an elaborate, standardized colour-grading system, sapphires and other coloured gemstones have no such similar way to assess colour across the board. This lack of uniformity means that it’s harder to compare two sapphires since one won’t be graded “D” and other “J.”
Saturation is the most important aspect of colour grading because it has the most direct effect on the final price for the stone. Too much saturation makes the stone look dark, while too little saturation makes the gem look too pale. The optimal saturation in coloured stones is Moderate to Strong.
Sapphires come in blues, with the lightest being Sweden princess blue and the darkest being navy or black. The most prized colour is royal blue, which is in the middle of the scale. As the most prized, however, it is also the most expensive. Camelot and commodore blues, which are one shade lighter and darker, respectively, are similar in hue but slightly more affordable.
The colour and saturation of pink sapphire also vary greatly. They range from pale, baby pink to hot pink shades that might appear violet. If the stone is red, it will be called Ruby, not Sapphire.
Besides the renowned blue and pink sapphire, there is the Padparadscha Sapphire, an extremely rare and sought-after pink-orange fancy sapphire originally found in Sri Lanka.
This sapphire can fetch over $20,000 per carat. The name comes from Sanskrit/Sihalese “padma raga,” which means “lotus color” since the stone’s color is reminiscent of a lotus flower.
Colorless, yellow, and green sapphires are significantly less prized.
Pink Sapphies and Ruby
Most sapphires on the market today have been heat-treated to improve their clarity and color. Untreated stones that are free of inclusions and possess superior color are rare and expensive, but because heat treatment is so commonplace, a heat-treated sapphire can still be valuable.
Historians found evidence that Romans heated sapphires to increase colour and clarity and finding an untreated pink sapphire in its natural state is very rare. They usually come with lab certification to prove it.
When purchasing for sapphires, it is always good to enquire on the treatment of the stone.
In terms of price, the treatment of a stone will greatly affect the price. To put it simply, the most expensive and rare Sapphires will be untreated, most commercial Sapphires will be heat treated while the cheaper stones will be surface diffused or Beryllium treated. The cheapest Sapphires available on the market today are the fissure filled Sapphires that have cobalt glass in them to improve the color.
The degree of visibility through a sapphire is known as its transparency. It is an often-overlooked characteristic when discussing sapphires. Transparency is designated as follows:
· Transparent - objects look clear and distinct through the stone. These sapphires usually have excellent brilliance despite any inclusions they may have.
· Semitransparent - objects look slightly hazy or blurry through the stone
· Translucent - objects are difficult to see through the sapphire. Light can pass through, but it is somewhat diffused.
· Semi-translucent or semi-opaque - a small fraction of light passes through the stone
· Opaque - almost no light passes through the stone
The only two locations that deserve a mention because they will greatly increase the price of a Sapphire are Burma and Kashmir. Fine quality Sapphires from these two locations are considered the best in the world and will fetch a premium simply because of where they come from.
Sapphire transparency ranging
from Transparent to Opaque.
Transparent is ideal.