The blue sapphire – the most valuable of all sapphires
Lady Diana gave blue sapphires a much-needed image boost when she became engaged to Prince Charles, who gave her an engagement ring with a blue sapphire surrounded by diamonds. But the blue stone was well known long before Lady Diana wore it on her finger:
blue sapphires were often used to make jewelry for medieval kings and bishops.
In ancient Greece and in the Middle Ages, the blue stone was said to be able to cure eye diseases and free prisoners.
Incidentally, before the 19th century, when people spoke of sapphires, they always meant the blue sapphire. It was only later that pink, white, green, violet, yellow and padparadscha sapphires were discovered.
A sapphire as blue as a cornflower
The word sapphire comes from the Greek for “blue”.
The most valuable sapphires have a rich, deep and clear blue color, often referred to as cornflower blue. In general, sapphires can have a wide range of blue hues, from light cornflower blue to dark, almost black blue.
There are also blue sapphires that change color depending on the lighting. They are blue in daylight, but in artificial light their color shifts to violet.
The sapphire as a piece of jewelry
A sapphire, even if it is intended as an investment, does not have to be kept in a safe. Its hardness makes it ideal for all types of jewelry, from rings and earrings to necklaces. The blue sapphire also looks good on brooches.
The combination with diamonds suits this stone particularly well: anyone who wears a blue sapphire framed by diamonds will attract a lot of attention.
Origin and mines of blue sapphires
The most valuable blue sapphires come from the Kashmir region in the Himalayas. In the late 19th century, blue sapphires were discovered after a rockslide and found their way into many Western royal and noble houses. Unfortunately, the mine was depleted within a few years. Smaller sapphire deposits were later discovered in the vicinity, but these have also been exhausted.
In addition to Kashmir, high-quality sapphires have also been found in Burma. Here, the blue gemstones are usually mined together with rubies.
The largest blue sapphire found to date was mined in Sri Lanka. The so-called “Star of Adam” weighs a whopping 1404 carats. Its value is estimated at around 90 million euros.
Presumably, the first blue sapphires came on the market from Sri Lanka: the legendary Queen of Sheba is said to have mined blue sapphires here.
Most of the blue sapphires on the market today come from Madagascar.
Other mining areas include Afghanistan, Cameroon, Nigeria, Pakistan, Rwanda, Tanzania, Thailand, Vietnam, the United States and Australia.
Unfortunately, Australian stones often have a green tinge, which has a negative effect on the price.
The place of origin is important for determining the value of blue sapphires. Several sapphires of exactly the same quality, with the same cut and the same size, but from different mining areas, will be priced differently. The highest price will be set for blue sapphires from Kashmir, followed by Burma, Sri Lanka and Madagascar.
Hardness of blue sapphires
The blue sapphire is the second most valuable corundum after the ruby. Like all corundums, it also has a Mohs hardness of 9. This makes it particularly resilient and resistant to signs of wear.
Heat treatment of blue sapphires
A large proportion of sapphires are heat-treated to improve their color. They are heated in a furnace for this purpose. A distinction is made between heat treatment at a high temperature, which is easy to detect, and at a low temperature, which is difficult to detect. It is common practice for sapphires to be heat-treated, but such treatment must be stated in the certificate. The degree of treatment must also be stated in the certificate.
Most common cuts
The most common cut for blue sapphires is the oval cut. However, round or cabochon cuts are also found.
Depending on the shape, gemstone cutters try to cut the largest and highest quality sapphires possible from a rough stone.