September's Birthstone: A Guide to the Hierarchy of Sapphires

September’s birthstone is a firm favourite among the Catherine Southon team - the sapphire.

Sapphires have been among the world’s most prized gemstones for centuries, celebrated for their exceptional beauty, remarkable durability and extraordinary range of colours. Although blue sapphires are the most iconic, these captivating gemstones can be found in a large spectrum of hues.

But what makes a sapphire desirable? And how can you distinguish a good sapphire from a truly exceptional one?

From colour and clarity to origin, treatment and size, there are several factors that determine a sapphire’s quality, rarity and value. In this guide, we explore the hierarchy of sapphires and the key characteristics to look for when buying or selling these sought-after gemstones.

Sapphire Mines and Origin

Ceylon Sapphires

The most common and accessible sapphire is the Ceylon sapphire. Sri Lanka has produced sapphires in significant quantities for centuries, making Ceylon one of the best-known and most widely available sapphire varieties.

Arguably the most famous Ceylon sapphire is the 12-carat sapphire cluster engagement ring worn by the Princess of Wales, inherited from her predecessor, Lady Diana. Its vivid blue colour and timeless diamond setting have helped cement the gemstone’s enduring association with royalty, elegance and prestige.

Burmese Sapphires

It is widely acknowledged that Burma (Myanmar) produces some of the world’s finest sapphires. Burmese sapphires are particularly renowned for their highly saturated, intense royal-blue colour, which makes them exceptionally desirable among collectors.

The historic Burmese mines produced sapphires in considerably smaller quantities than Sri Lanka, and fine Burmese stones are typically larger in size. As a result, fine-quality Burmese sapphires can command a significant premium, with exceptional examples valued between 50-100% more than comparable Ceylon sapphires

Kashmir Sapphires

Kashmir sapphires occupy an almost mythical position in the world of gemstones. Discovered in a remote mountainous region of northern India in the late 19th century, the Kashmir deposits were largely exhausted by the 1920s, making genuine Kashmir sapphires exceptionally rare today.

Their distinctive colour is quite different from the intense royal blue associated with Burmese sapphires. Instead, Kashmir sapphires are celebrated for their soft, velvety cornflower-blue colour, often accompanied by an extraordinary silky appearance. Due to their extreme rarity, exceptional Kashmir sapphires also command prices x10 greater than Burmese sapphires, placing them firmly at the pinnacle of the sapphire hierarchy.

Coloured Sapphires

While blue sapphires remain the most recognisable and traditionally sought-after sapphire colour, coloured sapphireshave steadily increased in popularity with collectors and jewellery buyers over the past decade.

Pink sapphires are particularly popular for their romantic and feminine appearance, ranging from delicate pastel pink through to vivid, highly saturated ‘hot’ magenta. 

Yellow sapphires are bright, cheerful and highly eye-catching gemstones, ranging in colour from delicate lemon and pale yellow through to rich, saturated golden hues. Compared with pink or blue sapphires, yellow sapphires can offer a more accessible entry point for buyers at auction, although particularly fine examples can still command significant prices. 

At the top of the coloured sapphire market sits the extraordinarily rare Padparadscha sapphire. The name Padparadscha is derived from a Sanskrit term for lotus blossom – reflecting their delicate pink and orange colour, creating an almost peachy, sunset-like colour. True Padparadscha sapphires are rare and their highly specific colour makes them sought-after by collectors. They saw a resurgence in the public eye when Princess Eugenie chose a Padparadscha sapphire cluster ring for her engagement to Jack Brooksbank in 2018.

Sapphire Treatments

Understanding sapphire treatments is essential when buying a sapphire at auction, as treatments can have a significant impact on a gemstone’s desirability.

Sapphire treatments are processes used to enhance a gemstone’s natural appearance, most commonly by improving its colour and clarity. Heat treatment is by far the most common enhancement, and the majority of commercial-grade sapphires have undergone some form of treatment.

Heat-Treated Sapphires

Heat treatment involves subjecting sapphires to high temperatures to enhance their colour and appearance. The process can reduce or remove colour zoning and 'silk' inclusions. Heated sapphires are widely accepted within the international gemstone trade, provided the treatment is disclosed. Consequently, heat treatment does not automatically make a sapphire undesirable or prevent it from achieving a strong price at auction. 

Lead-Glass Filled Sapphires

At the other end of the spectrum are lead-glass-filled sapphires, which are generally far less desirable to collectors.

This treatment involves filling fractures within a low-quality sapphire with lead glass to improve its apparent clarity and transparency. Unlike a traditionally heat-treated sapphire, glass-filled stones are considerably less durable. The glass filling may is vulnerable to heat, chemicals, abrasion and other forms of damage. As such, they are of significantly less interest to serious collectors

Untreated Sapphires

For many collectors, the ideal stone would be an untreated sapphire. These gemstones remain in their natural state, having been cut and polished but without artificial enhancement. Natural, untreated sapphires are considerably rarer than their heated counterparts. If an untreated sapphire also possesses exceptional colour, clarity, size and desirable geographical origin, it can command a substantial premium at auction.

One of the challenges for an auction buyer is that heated and unheated sapphires can appear virtually identical to the naked eye. For valuable sapphire jewellery, we will often obtain a gemmological laboratory report from a respected laboratory such as GIA.

Our Silver & Jewellery auctions regularly feature a strong selection of sapphire jewellery, including sapphire engagement rings, earrings, pendants and brooches. Whether you are a seasoned sapphire collector or looking buy your first piece, our auctions offer an opportunity to discover exceptional jewellery at a range of price points. Sign up for our catalogue alerts below to be among the first to see upcoming jewellery lots and explore the latest auction catalogues.