Sapphire

Sapphires, since their discovery in ancient times, have rarely fallen out of fashion’s favour. Their timeless elegance and beauty has made them one of the most popular precious stones used in jewellery. The deep blue of a sapphire is distinctive, and carries spiritual as well as physical value. A blue sapphire’s deep hue is beguiling because of its visual link to the sea and sky which are both intangible elements possess an ethereal quality. The magic of a sapphire is particularly potent when one considers that, before it is polished and cut, it lay buried beneath the ground, and is unearthed from the dark ground as if fragment of the sea or sky had been shattered.

Royal Admirers

One of the first cultures to recognise the beauty of the sapphire were the Ancient Egyptians, who are believed to have imported sapphires from Sri Lanka, where they are still mined today. The Persians believed that the world was balanced on a sapphire, and that the light reflecting through it accounted for the colour of the sky.

In Western civilisations sapphires have held royal connotations, because their traditionally sky-like colour has often been taken as a symbol of celestial wisdom and immortality; they feature on the oldest European crown that belonged to a Visigoth king, and the oldest jewel on the English crown is the sapphire of St Edward. Queen Victoria was also an admirer of sapphires. She was given a sapphire brooch surrounded by small diamonds by her husband as a wedding-present in 1840, which she adored and left to the Crown in her will. In more recent years, Princess Diana received a 12 carat sapphire engagement ring surrounded by fourteen solitaire diamonds and set in 18 Karat white gold. The ring was given in 2010 by Prince William to his future wife, Kate Middleton, which spurred a resurgence in sapphire engagement rings.

In Catholic tradition, bishops and cardinals favoured sapphires for their rings, as a reminder of the celestial powers granted to them. Since bishops were required to pay for their own rings, however, much-cheaper amethysts have been considered a suitable alternative owing to their deep purple colour resembling communion wine.

Many Hues

Sapphires, like rubies, are a member of the corundum family and structurally almost identical. The difference between the two stones is the presence of chromium in rubies, which is what gives them their scarlet pigment. For this reason, the only colour a sapphire certainly cannot be is red. Together with rubies, sapphires are one of the hardest gemstones excluding diamonds. Iron and titanium are the principle chromophores that provide sapphires with their blue colour. Although, sapphires are usually desired for their famous blue tone, they are available in a diverse range of other colours, from pink to yellow to green. They have even been found in several shades at once, although such cases are rare. One coveted shade of sunset pink is known as the Padparadscha sapphire.

Colour Change and Bi-Colour Sapphires

Colour change and bi-colour sapphires are another extremely rare form of sapphire. Like a chameleon the stones dramatically change colour in different lights. Colour change gems shift subtly between shades, typically from violet-blue to purple-red in incandescent light like electric bulbs or candle light compared to natural sunlight. Stones from south-west Tanzania frequently appear blueish green in daylight but transform to a reddish-brown in incandescent light. The colour change is caused by the absorption of the different light’s wavelength by the sapphire, which contains traces of metal impurities, such as chromium (Cr) and the minor ion, vanadium (V3+)

Bi-colour sapphires which contain two colours. The colour zoning of two different colours within a single gem is caused by an uneven distribution of colour during the crystals formation. During this formation trace elements change so that patches of two colours are visible to the naked eye. Bi colour stones do not change colour with the light but their different colour zones remain and a gradual colour shift is visible running across the surface of the stone. Sometimes the colour shift in colour zones is clearly divided and in other gems it is more subtle. The ambiguity lends the stones an exceptional uniqueness: no two stones really are ever the same!

Padparadscha Sapphires

The name for this unusual strain of sapphire stems from the Sinhalese word for an aquatic lotus blossom that shares a similar colour scheme. These rare sapphires bear a unique mix of orange and pink, were originally  found solely in Sri Lanka but deposits have more recently been found in Madagascar and Tanzania.

In the 1990s the market saw a mysterious increase in padparadscha sapphires. The reason for this increase, it transpired, was not a discovery in the mines, but in the lab! A radical new technique was discovered, whereby heat treating pale pink sapphires at extreme temperatures transformed the stones into deep pinky orange padparadscha look-a-likes. The colour change is created by the presence of beryllium in the poorly coloured pink sapphires.

Sources

The majority and finest Sapphires are found in mines in the Far East: Kashmir, Burma and Sri Lanka (listed in order of value):

Kashmir sapphires are highly prized and extremely rare. The value is increased by the few examples of Kashmir sapphires superior quality. Kashmir sapphires are often described as ‘velvety’ due to their rich colour. The cornflower blue tint is highly distinctive and easily recognisable to the knowledgeable eye. They were first mined and treasured by the local Maharajah’s of Kashmir. In 1887 a geologist discovered two locations within the Indian province of Kashmir in which sapphire stones can be found. Some sapphires have been found in the mines as large as an aubergine! One of the locations is called the ‘Old Mine’ and includes the pits within the valley and the second is located on the valley floor below the Old Mine. The rarity of a Kashmir sapphire is increased thanks to the danger in accessing the mines over the China and Wardwan River across a rope bridge elevate 11,550 ft. The contested territory and resultant conflict between India and Pakistan adds an additional difficulty in mining sapphires.

Burmese sapphires are considered of very high quality, and as such are valuable. Careful examination under a microscope is the simplest way of deciphering whether a sapphire is Burmese, as their inclusions are unique to them. While Sri Lankan needles tend to be longer, often spanning the width of the stone all together, Burmese inclusions form delicate clusters. They are usually a denser blue than the watery Sri Lankans, with those of particularly excellent quality resembling Kashmir stones in colour, with the added benefit of being easier to find in larger sizes. Indeed, one Victorian diplomat returned from Burma with a 907 carat sapphire in hand. In some cases, the geographical environment of a Burmese sapphire might infuse it with iron-rich rutiles, which add a brown silk to them.

Sri Lanka sapphires (sometimes known as Ceylon sapphires) come from mines which have been producing gems for thousands of years; Marco Polo used sapphires to win over Kublai Khan, which were allegedly Sri Lankan in origin. The sapphires are found in alluvial deposits, carried by the river from the mountains and harvested by use of baskets and rods. The process has been described to look something like fishing. Sri Lankan sapphires are also of typically good quality, although usually paler in colour than those from Kashmir. Owing to their environment, they sometimes include traces of zircon, a mildly radioactive mineral which provides the stone with a halo effect. They often contain inclusions, such as long intersecting white needles and fissures. These inclusions are rarely seen by the naked eye, and although they detract from the objective value of the gem, they have the advantage of being difficult to fake, indicating that the stone is genuine.