Characteristics of Australian Sapphires

_{a teal sapphire and a party sapphire}

When learning about the particular characteristics of a gemstone from a particular country or region, the aim is to converge on certain qualities that distinguish gemstones at a general level. As there will always be outliers, with certain sapphires containing features that are similar to those from other parts of the world. With Australian sapphires, the same principle applies. However, the distinct qualities of sapphires from Australia, in general, are worth engaging, in a market that is dominated by a number of Asian players, with each of them trying to distinguish themselves with their own gemstone offering.

What Colour are Australian Sapphires?

Colour is a key variable in sapphires. Unlike diamonds, sapphires are valued and sought after for their colour. With the exception of white sapphires, sapphire colours vary in terms of the type of colour, the level of concentration of colour, and the number of colours that are present in it. It is important to understand that colour in sapphires is not an innate quality; as the colour that is present in the gemstone is determined by the presence of external elements, which, depending on the level and combination give rise to the various colours that are present in them. Australian sapphires are known for their higher iron content, which tends to make Australian sapphires more varied in their colours. The first thing to know about colours in Australian sapphires is the prevalence of a number of colours. Besides the popular Australian blue sapphire (a deeper blue), this variety of gemstones also come in yellow, green and even purple.

Dark to Lighter Coloured Sapphires

A typical characteristic of Australian sapphires is their darker tone. Whilst colours like blue are among the most popular colour types in the sapphire family, a number of sapphire producing countries specialise in this particular hue. However, Australian sapphires, the blue ones which are the most prevalent type, come in a notably darker shade. Whilst lighter and medium tone blue sapphires are also present, Australian sapphires, even those that come in colours like purple and even light coloured sapphires like yellow, come with a darker tone. However, it would be wrong to generalize Australian sapphires as uniformly dark in their colours. As Australian sapphires are also found in light to medium tones, with those verging on the lighter side being more prevalent, however, one notable factor, which could be viewed as a weakness from a certain perspective, is that Australian sapphires tend to be less vivid in their colours.

Presence of Colour Banding

Colour banding is a phenomenon where distinctions begin to emerge within the very same colour in a particular object or image. This is considered to be an unfavourable feature in colour presentations: where visible lines cut through a coloured image, generating a divided look. Colour banding is a common sight in Australian Sapphires, but interestingly this feature often works to its advantage, where the banding of a single or multi-colours within the gemstone, where the dividing lines within the stone help create an interesting visual effect. In some varieties of Australian gemstones, the banding of colours is a feature that is more strongly present, producing an overall effect, where the colour or colours break, and the divisions between these colours or colours via these lines produce a striking effect. A feature that is most notably present in a popular version of Australian sapphires, is known as parti sapphires. 

Multi-Coloured or Parti Sapphires

The parti colour effect emerges as a result of a coarse banding of colours within the single gemstone; which gives rise to the parti coloured effect, where two or more colours are spread across the gemstone. Unlike two-toned sapphires with sapphires where the colours are cleanly separated out at a certain part, usually the middle, of the gemstone. In the parti variety, the various colour bands of the gemstone are wide enough, gives rise to the separation between colours such as green and gold or blue and yellow. With the colour bands alternating between each of the two or three colours. However, the parti coloured sapphires, on average are not always best when it comes to the separation of colours, with some gemstones having a predominance of a single or two colours, but are unevenly dispersed, or with certain gemstones having a predominance of a single colour. 

The Mineral Character of Australian Sapphires

Australian sapphires are identical to other corundum based gemstones that are mined from other parts of the world in terms of their chemistry. However, sapphires mined from the land down under do feature higher iron content. The greenish-yellow, green, yellow and brown sapphires mined from this part world are notable, with regions like Queensland being notable for their greater levels of iron. Part of the reason for this, a point which we expand upon in our Education page on sapphire mining in Australia, is that many of this nation’s sapphire stones are taken from basalt, which corresponds to the sourcing of Australian sapphires, many of which are taken from primary sources near volcanic rocks and areas close to such historical activity, which sets them apart from nations like Ceylon where secondary sources dominate. Australian sapphires also feature a higher percentage of vanadium, which is probably the reason why Australian sapphires have a greater number of parti and bi-colour sapphires.

Are Australian Sapphires Valuable?

This is a tricky question since the value of sapphires comes down to a number of factors. Besides the colour, carat, clarity and cut, the treatment the stone has been subjected to (curing) also play a key part in determining the value of the gemstone. Sapphires, like diamonds, are valued for being larger in size (carat), good cut (high reflection and glow), clarity (presence of few or no inclusions), and importantly colour. However when it comes to Australian sapphires, one must consider the unique characteristics: with their parti coloured ranges, gemstones with a varied colour range that extend from very dark to extremely light tones means that the factors of measuring sapphire quality must be viewed in light of the attributes of sapphires. 

Treatment of Australian Sapphires

The colour of Australian sapphire is often greatly affected by silk, which is a prevalent feature in sapphires sourced from this part of the world. The silk in sapphire gemstones refers to microscopic rutile crystals that developed inside the gemstones. The presence of silk inclusions is viewed negatively as they tend to lower the value of sapphires by affecting the dispersion of colour within the gemstone. However, on the positive side, the rutile crystals can also create the “star stone” or asterism, which is a highly desirable effect in a gemstone. Affecting the character of sapphires is often made via their treatment: which involves the heating of the gemstone. This is an industry-accepted practice and is used by jewellers to improve the natural qualities of the sapphire. In Australia, low heat methods are used to enhance the gemstone, usually those which are darker in tone.

Environmentally Friendly Character of Australian Sapphires

With the rise in demand for sapphires around the world, the popularity of Australian sapphires has also started to rise. Whilst the market for sapphires have been dominated by countries in South and South-East Asia, Australia is a dominant force in the diamond industry, and the mineral trade has meant that the gaze is being directed towards its great sapphire potential. Australia as a vast country with great mineral potential, is home to one of the largest known sapphire deposits in the world, with the Queensland mine believed to hold reserves of 100 million carats of sapphire. Given the vast potential in Australia, foreign mining companies and local governments have begun to pay attention to its mining potential. Combined with the growing demand for sapphires, there has been an increase in demand for gemstones that are minded ethically, and Australia, among the few developed economies, along with the United States that is engaged in the sapphire trade is being looked at as a solid option for ethical gemstones. The shift towards Australian sapphires has been driven by growing interest among Australian jewellers who are looking at them as a viable local option. A key factor that underlies the ethical character of Australian sapphires is the strong laws regulating the mining industry and labour regulations when it comes to employee well-being which makes gemstones from the land down under a great option.