Australian Sapphire Guide

Australian Sapphire Guide

Sapphires, among the world’s oldest gemstones, trace their origins back billions of years. These noble gems reflect the untamed beauty of the Australian wilderness, sourced from the ancient landscapes of the New England Fields in northern New South Wales and the gently rolling hills of Central Queensland.

With a colour palette ranging from oceanic blues and forest greens to wattle yellows and mesmerising parti tones, Australian sapphires boast an unparalleled variety.

Quick Facts about Australian Sapphires

Hardness

Australian sapphires rank 9 on the Mohs scale of hardness, second only to diamonds. This high hardness makes them resistant to scratching and enables a beautiful, lasting polish. These gems are also highly durable, with excellent resistance to chipping and sudden temperature changes.

Volcanic Origins

Unlike their Sri Lankan and Burmese counterparts, which form in metamorphic environments, Australian sapphires are born from volcanic activity. These gems crystallise from mineral-rich lavas produced by ancient volcanic eruptions.

Composed of Corundum

All sapphires, including Australian ones, are made of crystalline aluminium oxide, also known as corundum (Al₂O₃). With a specific gravity of 3.9–4, they are prized for their durability and beauty.

What Makes Australian Sapphires Special?

On the eastern side of Australia, Tertiary volcanic deposits—dating back up to 40 million years—serve as the primary source of these gems. While sapphire deposits are found near these volcanic regions, only a few areas yield stones in quantities large enough for commercial mining.

Key Mining Regions

• New South Wales: The New England district near Inverell and Glen Innes.
• Queensland: The Anakie Gemfields, near the towns of Sapphire and Rubyvale, west of Emerald.

The Beauty of Colour Banding in Australian Sapphires

Australian sapphires are renowned for their distinct colour banding, where zones of blue, green, and yellow appear in harmonious patterns. This natural feature often allows for the cutting of stunning bi-colour or parti sapphires.

• Parti Sapphires: These feature distinct bands of blue, green, and yellow. The rarest specimens display all three colours.
• Teal Sapphires: These showcase a captivating blend of blue and green, with flashes of each colour depending on the light.

The intricate trigonal crystalline structure of Australian sapphires results in their uniquely varied and vibrant colours, making them some of the most fascinating gemstones in the world.

Main Colours of Australian Sapphires

Blue

The most common colour, comprising 80% of Australian sapphires. Variations include Cornflower, Royal, Midnight, Steel, and Indigo, with their vibrancy influenced by iron (Fe) content.

Green

Green sapphires are a rare and prized blend of blue and yellow, with their depth of colour depending on iron concentration. Darker greens are particularly valuable.

Yellow

Bright and radiant, yellow sapphires owe their colour to iron ions (Fe³⁺). Higher concentrations can produce golden hues, while the addition of magnesium (Mg) creates stunning orange tones.

Parti Sapphires

Featuring a mix of blue, green, and yellow, Australian parti sapphires are globally unique. Their distinct banding ensures that no two stones are alike, enhancing their allure and value.

Teal Sapphires

Teal sapphires, with their exquisite fusion of blue and green, are becoming increasingly sought after. Australia is the leading producer of these gems, setting global trends with their vibrant and distinctive hues.

Australian sapphires are a testament to the continent’s ancient geology and unparalleled natural beauty. From their remarkable durability to their unique colour combinations, these gemstones are a treasured symbol of the Australian landscape and heritage.