Sapphires: What to look for when choosing a Sapphire

Sapphires are well known for their deep blue colors – such as the one seen in Princess Diana’s iconic engagement ring. However, Sapphires also come in a wide range of colors:

Sapphires belong to a class of minerals called Corundum, which is a form of Aluminium Oxide. Blue Sapphires occur as the result of iron and titanium being present in the Corundum, whilst colors such as yellow, green, gray, black, purple and pink are due to other trace minerals – and in the case of pink sapphire – due to trace elements like Nitrogen.

Rubies are also formed from Corundum, except that their color is due to the presence of chromium – which is responsible for the gemstone gaining its red color.

Gemstones, such as Sapphires and rubies, derived from Corundum are twice as hard as topaz. This is important to know since most people, except jeweler’s with a trained eye, are unable to tell the different between sapphires and topaz. The degree of hardness is relevant to take into account when buying a ring, particularly if the wearer will be subjecting their ring to a fair amount of wear and tear in the course of their daily work.

Sapphires are found more widely than rubies. This is partly due to the fact that whilst the chromium in rubies is responsible for their red color, it is also responsible for causing cracks and fissures in the crystal. This restricts their growth and development. However, with Sapphires, the minerals titanium and iron that are responsible for the gemstone’s blue color, do not restrict the growth of the Sapphire Crystal. This results in greater numbers and larger sizes of Sapphires.

There are two main aspects to consider when buying a Sapphire: The color – also known as the hue – and the appearance of any blemishes

The hue:
The intensity of the hue determines how expensive the sapphire will be
Some dark blue sapphires have poor reflective qualities and can appear black in low light. These should be avoided. The most sought after shade of blue for sapphires is a deep cornflower blue.

Blemishes:
A sapphire should have minimal amounts of blemishes to give the gemstone good clarity. A sapphire should have good clarity and light reflective qualities. However, some blemishes – particularly ones called “silk” are not necessarily a bad thing in a sapphire, as their presence can indicate the absence of heat treatment.


Heat treatment is commonly used for both Sapphires and rubies to eradicate flaws and improve their color and perceived quality. It has been estimated that only 0.5-1% of the sapphires that come out of the ground are of gemstone quality. Natural Sapphires are therefore more rare and valuable

Famous Sapphires

To truly appreciate the beauty of a natural sapphire, untreated by heat or chemicals – unlike most commercial sapphires today – we need to look at some of the most famous natural sapphires to observe their unique qualities. Although a natural stone may not always be totally perfect, its beauty can be seen in its individuality.

However, whilst we may not be able to afford a huge natural sapphire ourselves, owning even the smallest natural stone can bring joy to the wearer, knowing that their sapphire is unique to them.

Let’s take a look at some of the most famous sapphires and their unique individualities:

Star Sapphires:

These gemstones are perfect examples of how certain types of “imperfections” (known as inclusions) can add beauty to a sapphire. A star sapphire exhibits a phenomenon known as “Asterism”. This is an anomaly that occurs when fibers of the mineral rutile intersect in such a way that when light is reflected upon the gemstone, it shows up as a six rays star pattern.

The Star of India

At a massive 563 carats, the Star of India is the largest and most famous star sapphire in the world. This fabulous gemstone possesses a milky quality due to the presence of tiny fibers of the mineral rutile, that create its star pattern. It is this magical star, set within the gemstone’s rich blue color that makes the Star of India sapphire such a highly valued jewel.

The Star of India was discovered approximately 300 years ago in Sri Lanka, where many high quality sapphires can still be found. The Star of India is currently housed at The American Museum of Natural History in New York.

The Star of Bombay

The Star of Bombay is another excellent example of a Star Sapphire. Weighing in at 182 carats, this beautiful Sapphire was given to Mary Pickford – a silent movie actress – by her film star husband, Douglas Fairbanks Sr. The Sapphire is housed at The Smithsonian Natural Museum of Natural History, in Washington DC.

The Black Star of Queensland

Accidently discovered by a small boy in a small mining town in North Eastern Australia in the 1930’s, this magnificent 733 carat oval shaped Black Sapphire is believed to be the largest Star Sapphire ever found.

The stone existed in its raw uncut state for many years, being used as a doorstop, before being sold to an Armenian born jeweler, Harry Kazanjian. It was he, who was responsible for cutting the Sapphire into its cabochon shape and discovering its “star” qualities.

The rays of the star are not as long as some of the other famous blue star sapphire. However, the intensity of the star pattern against the darkness of the black sapphire and its gold setting, makes this an amazingly beautiful gemstone.

Having made the Kazajian family extremely successful, the Black Star of Queensland Sapphire has changed hands several times and is still privately owned. It has been exhibited at The Smithsonian Natural Museum of Natural History.

Other Famous Blue sapphires

The Logan Sapphire

A flawless blue sapphire, weighing 423 carats is one of the largest faceted sapphires in existence. Cushion cut and set in a brooch surrounded by 20 round brilliant cut diamonds – with a total weight of 16 carats, this stunningly beautiful sapphire is housed at the Smithsonian National Museum of Natural History, where it was donated by Mrs. John A Logan, in 1960.

The Rockefeller Sapphire

The Rockefeller Sapphire is an internally flawless cornflower blue gemstone that weighs approx 62.02 carats. The Sapphire is flanked by cut-cornered triangular cut diamonds mounted in platinum. The Rockefeller Sapphire gets its name from one of its previous owners, John D. Rockefeller who bought the gemstone from an Indian Maharajah in 1934. This rectangular cut sapphire weighs approximately 62.2. The Rockefeller Sapphire sold for $3.03 million on 11th April 2001 in New York.

The Bismark Sapphire

Cushion cut and set in a magnificent platinum and diamond necklace, this 98.6 carat cornflower blue sapphire has a natural clarity with excellent transparency.

The Bismark Sapphire was purchased in the 1920’s by the husband of Countess Mona von Bismarck when they visited Sri Lanka, whilst on honeymoon. The Sapphire is believed to have originated from the Ratnapura district – a region that has produced sapphires and rubies from the times of King Solomon in the 10th century BC. The district continues to produce an excellent supply of good quality sapphires.

In 1967, the Sapphire was donated by Countess Mona von Bismarck to the Smithsonian Museum of Natural History of the Smithsonian Institution, where it continues to reside.

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