One of the most versatile and beautiful gems to be found, the sapphire can create an array of spectacular shades in any piece of jewellery. While blue sapphires are the most popular, the gem is also found in a variety of other colours.
The sapphire is a variety of the mineral corundum that contains traces of the compound aluminium oxide. While red corundum, containing different trace impurities, creates a ruby, corundum of any and every other colour is considered a sapphire. The characteristic feature of corundum is the hardness of the mineral, which leads to extremely resilient gems. Sapphire is one of the hardest gemstones to be found, second only to the diamond on Mohs Hardness Scale. The value of a sapphire is determined by its colour, purity, reflection (or optical properties), and size. Imperfections in the sapphire, such as clouds, opaque spots, strips, knots, and flakes, reduce its value.
The colour of a sapphire is borne from trace minerals, such as iron, chrome or metallic oxides, present in the corundum. These minerals are known as "impurities" in the corundum, but their significance is almost exactly the opposite. Instead of contaminating the corundum, they add to its brilliance by turning the otherwise colourless mineral into breathtaking hues. Sapphires are usually thought of as being blue but can be found in several other colours as well. The most popular colours of the sapphire are blue, pink, yellow, and a unique blend of pink and orange known as "padparadscha". The term sapphire comes from the Greek work sappheiros, meaning blue.
Sapphires are sometimes treated to improve upon their natural colour. They may be heated to approximately two thousand degrees Celsius, which intensifies the colour and may even better the clarity. Heat treatment does not damage the sapphire.
Types of Sapphires
Blue Sapphire: The sapphire has long been associated with the colour blue, and it is these sapphires that are the most sought after and prized. Sapphires can be found in all shades of blue, from a light, sky blue to a deep, piercing cerulean. The sapphire attains its blue tint from the mineral titanium. Sri Lankan sapphire mines produce some of the best blue sapphires in the world.
Although some cultures consider the blue sapphire to be a sign of bad luck, the sapphire traditionally symbolises fidelity. In ancient times, gifting a blue sapphire was a measure of one's love, trust, integrity, purity, and allegiance, thereby continuing to make the gem an accepted choice in engagement rings.
The largest blue sapphire to have been discovered is the sapphire of Queen Marie of Romania. This stone, a rectangular cushion-cut sapphire, was gifted by King Ferdinand to his wife Queen Marie in 1921. After her grandson King Michael left Romania, the gem was purchased by jeweller Harry Winston.
Pink Sapphire: Corundum is known as a pink sapphire when the trace mineral present in it is chromium. Like the variety available with the blue sapphire, the pink sapphire too can be found in a wide array of shades from soft pink to fuchsia.
For decades, pink sapphires could be found only in Vietnam, Burma, and Sri Lanka, in limited areas. But in the late 1990s, deposits of pink sapphires were found in southern region of the African island of Madagascar, making them extensively available. Madagascan pink sapphires are of the highest quality and are found in large numbers.
Pink sapphires are not traditionally heated to improve upon their colour in the way that blue or yellow sapphires might be. Pink sapphires are heated to a much lower temperature as most of the gems mined are already of superb quality. An exception can be made with Burmese pink sapphires (which are often mistaken for rubies), which require heating to enhance both their colour and their clarity.
Yellow Sapphire: The finest yellow sapphires in the world are found in the mines of Sri Lanka. Other countries such as Burma, Australia, Madagascar and Thailand also produce yellow sapphires, but none of these can compare to the quality and colour of the Sri Lankan gems. Yellow sapphires from Sri Lanka are known as pushparaga in Sinhalese and pukhraj in Hindi. These are also called "hyacinth" or "oriental topaz" and are honey yellow with brownish undertones. Ancient scriptures cite the primary Indian sources of pukhraj as the Mahanadi and Brahmputra rivers, the Himalayas, the Vindhyachal Mountains, Orissa, Bengal, and Kashmir.
Like blue and pink sapphires, yellow sapphires can be found in a range of shades from light to golden. However, yellow sapphires are not as popular as blue or pink sapphires and are therefore not as expensive as them either.
Yellow sapphires too can be treated at very high temperatures but are more valuable if treated at lower temperatures. The inclusions in yellow sapphires look like feathers and may be removed by treatment at high temperatures.
One of the most famous yellow sapphires was the Autumn Glory, discovered as late as 1993 in Australia. The stone originally weighed 103.5 carats, and was later fashioned into an oval cut weighing 30.25 carats. The Autumn Glory was lost while in transit to the USA and has still not been recovered.
Padparadscha Sapphire: The most exceptional and uncommon type of sapphire to be found is known as the "padparadscha sapphire". The gem has the distinction of being a sapphire with a rare combination of colours - pink and orange. Padparadscha sapphires are extremely rarely found, making this gem very valuable and expensive. The term "padparadscha" is Sanskrit for lotus, as the colours of the gem strongly resemble that of the flower.
The primary source of the padparadscha sapphire has, for thousands of years, been Sri Lanka. While some other countries have yielded similar stones in recent years, none can match the uniqueness of the Sri Lankan padparadscha sapphire. Madagascar produces some first-rate padparadscha sapphires as well, but these are sold at a price lower than the Sri Lankan padparadscha commands. In fact, it is widely believed that while sapphires from other countries may look very similar to a padparadscha, it is only the Sri Lankan gems that can be considered true padparadscha sapphires and that sapphires from other countries that have similar colours and characteristics should not be referred to by this term.
Star sapphire: Also known as "phenomenon stones", star sapphires are created by an illusion of light. Half-dome cut or cabochon sapphires sometimes display a bright, six-rayed star-like pattern or asterism, which is caused by the reflection of light from the inclusions in the sapphire. Heating a star sapphire will destroy these inclusions, known as rutile needles, and the star-like appearance will be destroyed.
Star sapphires are usually translucent or opaque, and are commonly found in Sri Lanka, the United States and Australia. They come in many colours, the most common being grey or blue. Because the scientific formation of the star-like appearance has only recently been learned, it was believed in ancient times that the star sapphire was a powerful and magical gem that would protect the wearer.
The most famous star sapphire is the Star of India, which is also the largest star sapphire known. Discovered in Sri Lanka, it is reputed to have been formed two billion years ago and is now on display in the American Museum of Natural History.
Kashmir Sapphire Mines
Sapphires were discovered in the Zanskar range of the Kashmir region as early as the 1880s. In 1882, F.R. Mallet of the Indian Museum first declared in the Manual of Geology of India after examining the stones, which had not been identified before, that they were in fact sapphires. Among the earliest known mines were those situated near the village of Soomjam in the district of Padar, which lies at a staggering altitude of 11,000 feet above sea level and is one of the highest villages on the southern side of the range.
When the king of Kashmir learned of the potential value of the gems found in his region, he deputed a regiment of soldiers to the mines to take control of them, allowing those who had already collected sapphires to keep their finds. From 1882 to 1887, mining of sapphires in the Kashmir region flourished, but declining profits and exhausting of resources forced official mining to be stopped for a number of years. Although the mines have sporadically been operative since 1905 (both officially and by poachers), the region is now considered rebel territory due to guerrilla activity.
Kashmir sapphires are usually blue, ranging in all shades from the palest to the deepest blue, and are sometimes very large. However, Kashmir sapphires may be intertwined - one or more crystals are twisted around another in their structure. The sapphires also frequently contain heavy inclusions, most of which are small and cannot be seen easily without magnification. The sapphires that were discovered in the early days of mining are still considered to be among the best sapphires in the world, but most of these mines have now been depleted.