Kings Plains Sapphire

September’s birthstone, Sapphires’ a truly mesmerizing gemstone with a rich history, potent symbolism, and popularity spanning over 2,500 years. Beautifully displaying their signature royal-blues, Kings Plains Sapphires are unearthed at the family-owned Wilson Gems Mine, situated in Australia’s famous Kings Plains gem field in New South Wales. During the late 80s, Australia was Sapphires’ leading miner, supplying 70 percent of the world market, but times have changed. Today, Kings Plains Sapphire’s nearing commercial depletion, accentuating the desirability, rarity, and value of their coveted royal Antipodean blues.

Hardness 9
Refractive Index 1.762 – 1.788
Relative Density 3.95 – 4.03
Enhancement Heat (Standard/Traditional Heat)


Few people realize that Australia is actually one of the world’s major Sapphire sources. Kings Plains Sapphire comes in beautiful, rich royal-blues with a highly-desirable medium (medium-light to medium-dark) saturation (strength of color) and tone (lightness or darkness of color).

Displaying excellent brilliance and transparency, expert cutting is absolutely critical for Kings Plains Sapphire. Every Kings Plains Sapphire’s optimally faceted in the legendary gemstone country of Thailand (Siam), home to some of the world’s best lapidaries, at the Wilson’s dedicated cutting house in the internationally acclaimed gem town of Chanthaburi. Featuring an eye-clean clarity (the highest quality clarity grade for colored gemstones as determined by the world’s leading gemological laboratories), they’re carefully orientated to maximize beauty, in a manner that doesn’t sacrifice brilliance for weight, with a superior polish that results in a beautiful luster, and an attractive overall appearance (outline, profile, proportions, and shape).

While both Ruby and Sapphires are classed as Type II gemstones (gems that typically grow with some minor inclusions in nature that may be eye-visible), Sapphires are usually cleaner (and larger) than Ruby, with an eye-clean clarity (no visible inclusions when the gem is examined approximately six inches from the naked eye) being the typical standard. Fine microscopic inclusions (called ‘flour’, ‘milk’ or ‘silk’) in some Sapphires can impart a ‘velvety’ or ‘sleepy’ appearance that boosts both beauty and value. Once you’ve settled on a color you like, look for a good shape and overall appearance (finish, outline, profile and proportions). While ovals are most common, Sapphires are available in other shapes and cuts. As stated previously, optimal cutting is absolutely critical for Sapphire.

Sapphires are pleochroic (different colors visible from different viewing angles), but this is not usually a concern. Gems with table-up pleochroism that detracts from their beauty will be priced accordingly. As usual, the visibility of pleochroism is determined by crystal orientation during lapidary. The aesthetic impact of color unevenness due to zoning (location of color in the crystal versus how the gem is faceted) or excessive windowing (areas of washed out color in a table-up gem, often due to a shallow pavilion) is also an important value consideration. Finally, pay attention to how transparency and inclusions affect Sapphires’ color beauty and subsequently, value. As with all gemstones, assuming everything else to be equal, size matters for Sapphires, and one 4 carat Sapphire will always be far rarer (and more expensive), than four 1 carat Sapphires.

Like all famous gemstones, Sapphire features in mythological and religious stories. Whether these really referred to what we know as Lapis Lazuli or blue gems collectively during antiquity is uncertain. According to Greek mythology, the first person to wear September’s birthstone was Prometheus. While Persians believed Sapphire’s reflections gave the sky its colors, Sapphire is mentioned in the bible: Exodus (24:10), the throne of God is paved with Blue Sapphire of a heavenly clarity, it is also one of the 12 ‘stones of fire’ (Ezekiel 28:13-16) set in the breastplate of judgement (Exodus 28:15-30). As one of the 12 gemstones set in the foundations of the city walls of Jerusalem (Revelations 21:19), Sapphire is also associated with the Apostle St. Paul. Sapphires have long symbolized faithfulness, innocence, sincerity and truth, so it’s not surprising that for hundreds of years they were popular engagement ring gemstones. Apart from being one of the world’s favorite hues, blues are also psychologically linked to calmness, loyalty and sympathy.

While Sapphire’s popularity as an engagement gemstone has been somewhat upstaged by Diamonds since the 50s, they are making a comeback. For example, in 1981 Prince Charles gave Lady Diana an engagement ring set with a stunning 18 carat Ceylon Sapphire and more recently (2011) Prince William tied the knot with Kate Middleton using the same engagement ring.

Defined as any process other than cutting that improves a gems’ appearance, durability, value or availability, 90 percent of all gemstones in the marketplace have been enhanced in some manner. As these processes have become an important part of the modern gem industry, enhancements are acceptable as long as they are disclosed, permanent, and stable. While gemmologists can often spot indications of gemstone enhancements, advanced scientific testing is frequently required for confirmation and absolute certainty.

Becoming malleable around 1900°C and melting at 2030°C, Sapphires can withstand incredible temperatures.  Sapphires also have no cleavage (i.e. very high toughness), allowing them to endure high temperatures with an acceptable breakage risk. Heating Sapphires to improve clarity or develop color has been used in some form for hundreds, if not thousands of years. Likely practiced in the sub-continent over 4,000 years ago, heating is one of the earliest known gemstone enhancements. Early references to the heating of gemstones include Pliny the Elder in his ‘Naturalis Historia’, c. 77 AD and two Egyptian papyri dating to the third or fourth century AD. The scientist Abu Rayhan al-Biruni not only developed the specific gravity scale, using it to identify many gemstones, but in his book, ‘The Book Most Compressive in Knowledge on Precious Stones’ (c. 1048 AD) he describes in detail the 1100°C heating of Corundum to remove dark colored areas. Interestingly, this is basically one of the same methods still used today. Referred to as ‘traditional’ or ‘standard’ heat, modern ‘low’ temperature enhancement involves heating Sapphires to 1200°C – 1700°C for anywhere up to an hour to 36 hours, often repeating the process to achieve the desired results.

While almost all Sapphires are heated, this is not always a simple ‘traditional’ process that originates in antiquity, with new techniques continuously being developed (e.g. heating with pressure, c. 2009). Often a sophisticated process that has taken experienced specialists’ decades to perfect, high temperature heating can significantly change a Sapphire’s original appearance (and value). For example, modern electric and gas furnaces can heat Sapphires to 1800°C (close to their melting point) for up to seven days, sometimes with this being repeated numerous times. These high temperatures allow the incorporation of additives, such as glass (filling cavities and cracks) and coloring agents (e.g. beryllium bulk diffusion to dramatically alter color). As these enhancements radically change the color and clarity of arguably inferior gemstones, Sapphires that have been heated with additives should be disclosed, and not simply described as ‘heated’.

Sapphires embody a gem’s quintessential ideals: breathtaking beauty, genuine rarity, and everyday durability; making it one of the world’s most coveted gemstones. Ruby and Sapphire are color varieties of the mineral Corundum (crystalline aluminum oxide), which derives its name from the Sanskrit word for Rubies and Sapphires, ‘kuruvinda’. Trace amounts of elements such as chromium, iron and titanium, as well as color centers, are responsible for producing Corundum’s rainbow of colors. Sapphire’s name is derived from the Latin, ‘sapphirus’, which in turn comes from the Greek ‘sappheiros’, meaning blue. This name is believed by some to originate from either the Hebrew ‘sappir’ (precious stone) or the Sanskrit ‘sanipriya’. Used to describe a dark precious stone, ‘sanipriya’ means ‘sacred to Saturn’ and this entomology is lent credence by the fact that Sapphire is regarded as the gem of Saturn in Indian astrological beliefs. Historically, ‘sappheiros’ usually referred to Lapis Lazuli rather than Blue Corundum, with the modern Sapphire probably called ‘hyakinthos’ in ancient Greece. Believe it or not, Sri Lankan Sapphires were reportedly used by the Greeks and Romans from around 480 BC, which provides evidence of the ancient trade routes used by our ancestors.


The finest Australian Sapphires can rival Sapphires from renowned localities with an historic pedigree, such as Ceylon (Sri Lanka). Australian Sapphires’ main sources are the New England (Kings Plains) fields, in northern New South Wales (NSW), and the Anakie fields, in central Queensland. Ranging from pastel through to midnight, the vast majority of gem-quality Australian Sapphires, approximately 90 – 95 percent by weight, occurs in various shades of blue. The second most prevalent color are teals (greenish-blues), followed by greens, goldens, and yellows. Occasionally color change (Alexandrite-like and greenish yellow to orangey pink), mauve, orange, pink, purple, and star (black or bronze very similar to those from Bang Kha Cha in Thailand’s Chanthaburi Province as well as blue, blue-gray, gold, and green) Sapphires are found, but they are extremely rare. Color banding is very common in Australian Sapphires and this feature is actually more prevalent and better developed than in Sapphires from other deposits. Coarse to very coarse banding of blues, greens and yellows results in the uniquely beautiful Particolored Sapphire. The most attractive of all Particolored Sapphires and one of the most beautiful gems of the entire Corundum family, is the Wattle Sapphire, whose blend of green and gold are reminiscent of Australia’s national flower the Wattle (Mimosa). Crystallizing in a more iron-rich environment Anakie Blue Sapphires’ are generally darker, when compared to Kings Plains, whose noted for its classic royal-blues.

Discovered in 1854, the Kings Plains Sapphire deposit is an ancient dry riverbed located northeast of the town of Inverell in the Australian state of NSW. The Wilson Gems Mine’s principal miner, John ‘Jack’ Wilson, has been working Australian Sapphire fields for well-over 50 years. Once one of the richest Sapphire fields ever mined, prior to 2019 every ton of earth yielded 6-8 carats of faceted gems. Now every ton of earth only yields 1-2 carats of finished Kings Plains Sapphires displaying their signature royal-blues. Most Sapphire crystals mined range in size from a grain of sand to the size of a pea, typically yielding small accents to two carat gemstones. Larger gems are rarely found. With mined land reclaimed into pastures replanted with native vegetation, the Wilson Gems Mine is environmentally friendly. As gullies and eroded areas are filled-in, the reclaimed pastures are actually more productive. The Australian Department of Mineral Resources actually wants every miner in the state of New South Wales to review the excellent rehabilitation processes at the Wilson Gems Mine. While Australia was once the world’s main Sapphire supplier, with the NSW gem fields accounting for more than half, Kings Plains Sapphire is now unfortunately nearing the end of its story, with the Wilson’s currently the deposits last remaining commercial mine.

Durability & Care

The world’s second hardest gemstone, Kings Plains Sapphire is an excellent choice for everyday jewelry (Mohs’ Hardness: 9). Kings Plains Sapphire should always be stored carefully to avoid scuffs and scratches. Clean with gentle soap and lukewarm water, scrubbing behind the gem with a very soft toothbrush as necessary. After cleaning, pat dry with a soft towel or chamois cloth.

Map Location

Click map to enlarge


More Gemstones View All