A DEEP DIVE INTO THE VALUE OF SAPPHIRES

In its very basic form a sapphire is simply the mineral corundum but several miles below the Earth’s surface under extreme heat and pressure, sapphires form over millions of years. 

Given the time it takes nature to produce these stones you begin to appreciate their worth & scarcity. 

Sapphires have long been associated with royalty & nobility for centuries. Princess Diana famously had a blue sapphire engagement ring. A 12 Carat oval Sri Lankan stone set in white gold. 

One of the largest sapphires affixed to the crown of the Crown Jewels is the Stewart sapphire and it  weighs 104 carats. According to Berganza, the Stuart sapphire’s earliest recording dates back to 1214 when it belonged to the Scottish Royal family. 

Due to the Stuart sapphire's historical connection with the royal family - it makes this gem virtually priceless. The record for the most expensive sapphire sold at auction however was the bluebelle of Asia at $17.3 Million. The bluebelle of Asia is a 392 carat cushion cut sapphire from Sri Lanka with peacock blue colour and excellent clarity. 

UNIQUE STONES 

Most people think of the colour blue when they hear of sapphires but did you know that natural sapphires can come in almost any colour of the rainbow? 

It is the many possibilities of trace elements within the stone corundum that give the colour, the element titanium gives sapphire its blue colour for example. 

The unlimited possibilities means that each natural sapphire is incredibly unique. You won’t find 2 natural stones that are the same. 

As such, rare and unusual sapphires are in essence irreplaceable. For example, Star sapphires. A star sapphire is a type of sapphire that reflects a star shape pattern of light within the stone. 

The optical phenomenon is usually caused by small needle-like inclusions of the mineral rutile. 

The star of Adam is the largest pure blue star sapphire in the world. It weighs 1400 carats & is estimated to sell for upto $175 Million at auction according to the BBC. 

However, not all sapphires that are mined will be as good quality as the star of Adam. In fact only a small percentage of any mined sapphires will be of high quality. So why is one sapphire worth more than $100 million while another won’t even be marketable? 

As with all gemstones, it all comes down to the 4 Cs of quality. 

WHAT DETERMINES THE VALUE OF A SAPPHIRE ? 

The four Cs of quality are; Cut, Colour, Clarity & Carat. 

COLOUR 

The most important factor when it comes to sapphires is colour. An undesirable coloured sapphire such as a very dark opaque blue sapphire wouldn’t have much value compared to other colours. 

The three main factors for judging a sapphire's colour are; hue, saturation and tone. 

Hue is the gemstone's basic colour. Gems can often be a combination of hues. 

Tone describes how light or dark the gemstone's colour is. Ideal tone varies from hue to hue. 

Colour saturation refers to how pure or intense the colour is. If the colour is diluted this lowers the value of the sapphire. The finest sapphires are vividly intense in colour. 

Some rare & exotic colours are valuable, including the orange-pink padparadscha sapphire and the colour changing sapphire. The orange-pink padparadscha sapphire gets its name from the Sinhalese word for Lotus Flower, where the stones are often found in Sri Lankan rivers. 

Whereas black sapphires are mined in abundance in Australia and also found worldwide. This means this variety of sapphire is fairly inexpensive. 

CUT 

Cut can refer to the shape which is the overall outline of the gemstone. It can also refer to the arrangement and shape of the facets. 

The shape and arrangement of its facets affect how light interacts with the stone and therefore a good gemstone cutter or lapidarist will evaluate the rough sapphire and cut in order to display more brilliance & colour. 

Deep cut sapphires preserve more weight and show off more colour whereas shallow cut sapphires appear bigger for their weight and look lighter than deep cut sapphires. 

CLARITY 

Clarify refers to the imperfections such as feathers, inclusions and silk that are visible inside a sapphire. The size, location and amount of imperfections will affect the value of the stone. 

Unlike diamonds there isn’t a widely recognised system for grading sapphires. Sapphires are graded by eye by looking closely at the different viewing angles to check whether any inclusions are visible. 

Even the finest sapphires are not expected to be free of inclusions and so the scale below goes from high quality clarity (1) to low quality (5)

1 - Very slightly included 

2 - Slightly included 

3 - Moderately included 

4 - Heavily included 

5 - Very heavily included 

Very heavily included stones will likely be less durable as the imperfections cause weakness in the stone. So these lower quality stones are more prone to chipping & cracks. 

CARAT 

A carat is a unit that expresses the weight of a gemstone. 

In general per carat prices increase with the overall carat weight of the stone. 

Large sapphires are much rarer than smaller sapphires. For example a 10 carat sapphire is worth a lot more than 10 stones that weigh 1 carat. 

The effect of carat weight from stone to stone varies by colour. Larger black sapphires are fairly plentiful but large padparadscha sapphires are extremely rare. 

Although the 4 Cs discussed here determine the value of a sapphire, there are some other factors that contribute to the gems' worth… 

COUNTRY OF ORIGIN 

Sapphires come from many countries around the world and they all have the mineral conundrum. The difference is in the different geological conditions in which they were formed. It is the different trace minerals that form the sapphires determine the varying qualities they possess. 

The shape of the rough stones, colour as well as the various inclusions within the mineral give information about where the stone comes from. 

The origin of the sapphire has considerable value on the gemstone. Kashmir (Northern India) has the highest prices for sapphires. Followed by Burma and Ceylon (Sri Lanka). This is due to both the rarity and the quality of the sapphires. 

Natural unheated sapphires that come from Kashmir, Burma & Sri Lanka will appreciate in value due to their scarcity (deposits are nearly totally exhausted) and demand remains unwavering. This makes for good investments in these stones. 

Worldwide production volume of sapphires of the finest qualities are declining significantly. 

A hundred years ago small deposits of sapphires were discovered in Kashmir which have now been exhausted. The extreme rarity of these historic sapphires gives them astronomical value. According to Sotheby’s, most high quality Kashmir sapphires sold at auction sell for between $100,000 to $1Million. 

Kashmir stones have a velvety appearance and their stones tend towards a slightly purplish blue. They have strong to vivid saturation and a medium to medium/dark tone. 

Sri Lanka produces some of the finest quality sapphires available in the market today. The sapphires come in  a light blue to dark blue. The darker the colour the finer the stone. As Sri Lankan sapphires tend to be on the lighter side of the colour spectrum, stones will often be cut deeper in order to bring out more of the colour saturation. 

Sri Lankan sapphire can be found in almost every colour for almost any budget. The saturation is typically medium to vivid & strong. The tone can be light, medium or medium-dark. Most blue sapphires on the market tend to show slightly grayish to violet-blue hues. 

Sapphires can also be found in mines around the world such as Thailand, Australia, Madagascar, Colombia, China and many others. These countries don’t command the same premiums however. 

HOW DOES HEAT TREATMENT AFFECT A SAPPHIRES VALUE  ? 

Around  95% of the world's sapphires are heated at around 1500+ degrees Celsius to improve their colour by dissolving any impurities such as silk. As discussed in the 4Cs of quality - this improvement in colour increases the value of the sapphire. 

Only a tiny percentage of the world's sapphires are natural unheated sapphires. There is no major difference between heated and unheated sapphires except their rarity. 

Sapphires can be lab tested to check for inclusions and it can be determined if a sapphire has been heat treated or not. 

It is recommended to always ask your jeweller if a stone has undergone any treatments. An unheated sapphire could command a 3X multiple of a similar heated sapphire. 

Poor quality stones that fail to improve colour with heat treatments will often use diffusion treatments to get beryllium to penetrate deep into the sapphire. 

While this improves the colour of the stone and makes stones marketable, stones that have undergone beryllium diffusion treatment will often be priced much lower than their only heated or natural counterparts. 

Other treatments such as glass-filled sapphires don’t have the same hardness as true sapphires. 

THE DESIRABILITY OF DURABILITY 

A factor that determines the popularity of sapphires as fine engagement rings is their durability. Rating 9 on the Mohs Scale for hardness, they are only second to diamond. This makes them unlikely to scratch & chip which is why they are great for everyday wear for engagement rings that can be passed down through generations.