This article serves as part of an ongoing series of profiles on the different varieties of precious & semi-precious gemstones. To view the entire list, click here.
Yellow sapphires - popularly known as Pukhraj in India, have always held a special place in history, surrounded by an aura of mystique and reverence. Legends speak of its ability to safeguard the wearer from malevolent forces while bestowing upon them good fortune and abundance. In ancient Greece, yellow sapphires were attributed with healing properties and were esteemed for their potential to restore health and vitality. Traditional medicine also embraced these gemstones as a valuable ingredient in remedies aimed at addressing a range of ailments.
Today, yellow sapphires have become increasingly popular as part of the modern jewellery aesthetic. An excellent example is the 10-carat square-cut yellow sapphire featured on Jenny McCarthy's engagement ring. Besides their exquisite beauty, these gems symbolize wisdom and success, making them cherished gifts to celebrate new beginnings.
Jenny McCarthy’s 10-carat yellow sapphire engagement ring
In this comprehensive profile, we delve into the captivating world of yellow sapphires - uncovering their origins, inclusions, astrological significance, and quality determinants.
1. Yellow Sapphires - Formation & Occurrence
With their range of canary hues and exceptional durability, pukhraj stones hold a special place among gemstone enthusiasts. These gemstones, belonging to the corundum mineral family, are known for their vibrant yellow colouration, which ranges from a pale lemon shade to a deep and fluorescent yellow.
Like all other sapphires, yellow sapphires too are formed through geological processes that take place deep within the Earth's crust. These gemstones are created in metamorphic and igneous environments, and they undergo intense heat and pressure, creating an environment conducive to the formation of corundum minerals – which is the crystalline form of aluminium oxide. These crystals are predominantly found in alluvial deposits, which are formed when minerals and gemstones are eroded from their original sources and carried by rivers and streams. Over time, these deposits accumulate in areas such as riverbeds where they can be easily accessed by miners.
During the process of their formation, certain impurities and trace metals such as iron can get trapped within the body of these minerals – which gives rise to the yellow colouration in these sapphires. Specifically, the intensity and uniformity of the yellow or canary shade depend on the concentration of iron within the body of each specimen.
Although the shade of yellow sapphires can vary, they can also sometimes occur in combination with other colours. “Pitambari” sapphires (also called Pitambari Neelam), for instance, are shades of yellow and blue in a sapphire, in varying percentages. These stones can also occur in a mixed shade of yellow and green – often known as Parti sapphires. Due to these multiple colour combinations, yellow sapphires are also sometimes referred to as polychrome sapphires.
A Pitambari (yellow-blue; left) sapphire & a Parti sapphire (yellow-green; right)
The occurrence of the pukhraj stone is widespread, with notable deposits found in various regions around the world. Sri Lanka or Ceylon, often referred to as the "Island of Gems," offers exquisite yellow sapphires known as "Ceylon Sapphires." Australia and Madagascar are other significant sources of high-quality yellow sapphires. While smaller deposits of these gemstones can be found in different parts of the world, these aforementioned regions have a rich history of mining and have consistently produced specimens with remarkable colour saturation, clarity, and overall desirability.
2. Where Are Yellow Sapphires Found?
Yellow Sapphires can be found in various regions across the globe, but some notable origins include:
- Sri Lanka (Ceylon): Sri Lanka is among the most popular source of origin for various gemstones – including yellow sapphires. These “Ceylonese” sapphires are renowned for their bright and pure colour, often occurring without any green undertones. This country is regarded among the best sources of yellow sapphires – with high-quality specimens often mined here.
- Madagascar: Yellow sapphires from Madagascar are known for their vibrant hues and exceptional transparency. The Ilakaka region in Madagascar is particularly renowned for its abundant deposits and northern Madagascar has also proven to be a fruitful source of yellow sapphires, which are extracted from alluvial deposits of basaltic rocks.
- Australia: The gemstone deposits in Queensland and New South Wales have yielded high-quality specimens - appreciated for their brilliance and high-quality mining practices. Australian Yellow Sapphires are highly regarded in the gemstone market, with colours ranging from vibrant yellow to intense gold and orange hues.
- Thailand: The gemstone industry in Thailand has long been associated with the cutting, polishing, and trading of Yellow Sapphires, making it a significant hub for these gemstones. Particularly distinctive are the deep yellow and golden sapphires, which are nearly exclusive to Thailand. However, it is worth noting that many sapphires sourced from Thailand undergo a common practice of beryllium-infused heat treatment to enhance their overall appearance.
While these are the most prominent sources of yellow sapphires, smaller deposits and occurrences of these gemstones can be found in various other regions worldwide including Myanmar, Tanzania, Russia and Brazil. Each location contributes its unique geological characteristics, resulting in yellow sapphires of varying colours and qualities.
3. Are All Yellow Sapphires, Indeed Yellow?
Yellow sapphires occur in a wide range of colours - spanning from a delicate pale yellow to an intense canary and orangish-yellow. The gemstone's colour can also vary in tone, ranging from light to dark. The presence of trace elements like iron and specific geological conditions during their formation contribute to this diverse colour spectrum. The most desirable yellow sapphires are those with a brighter and uniformly-saturated yellow colour.
In certain instances, pukhraj stones may also display secondary hues, such as golden, orange, or greenish undertones. These variations in secondary colours contribute to the unique character and allure of each yellow sapphire, making them distinct and individual gemstones.
Yellow Sapphires occur in a range of canary-yellow shades
4. Common Inclusions in Yellow Sapphires
Yellow sapphires, like most gemstones, often contain inclusions that add to their unique character and help identify their origins. These inclusions are formed during the natural growth process of the gemstone and offer valuable insights into its formation and geological history.
One common type of inclusion found in yellow sapphires is known as "silk." Silk inclusions appear as fine, needle-like structures resembling delicate strands of silk. They can affect the way light interacts with the gemstone.
Another type of inclusion commonly seen in yellow sapphires is the presence of feathers. Feathers are natural fractures within the stone that occurred during its formation and subsequently healed over time. These feather inclusions are usually small and have minimal impact on the overall quality of the yellow sapphire.
A ‘feather’ inclusion within a yellow sapphire
Yellow sapphires can sometimes contain traces of beryllium, which is intentionally infused into the gemstone through a heating process. This infusion of beryllium enhances the yellow colour of the sapphire, making it more vibrant and intense. In some cases, yellow sapphires, particularly those from Thailand, may undergo a treatment known as lead-glass treatment. However, this treatment is not desirable as it can negatively affect the structural integrity of the stone and is not stable. Yellow sapphires with lead-glass or beryllium are generally considered of lower quality and therefore are usually less expensive.
Inclusions not only contribute to the natural formation and identification of yellow sapphires but also offer a glimpse into their captivating stories. While flawless gemstones hold their own allure, these inclusions add a touch of uniqueness and charm to yellow sapphires.
5. Common Treatments & Enhancements of Yellow Sapphires
Treatments are sometimes applied to yellow sapphires to enhance their colour and clarity. The most common treatment is thermal enhancement. This treatment involves subjecting the yellow sapphire to high temperatures within a specialized furnace. The gemstone is carefully placed in the furnace and heated for a specific duration, with temperatures ranging from 1200°C to 1800°C. The exact temperature and duration are determined based on factors such as the desired colour and the specific properties of the gemstone. This process can improve the stone's colour and make it more vibrant. Even a pale-yellow sapphire can be transformed into a stunning gem through this heat treatment.
A simple heat treatment process is considered a reliable and effective way to improve the visual qualities of yellow sapphires, and it is widely accepted and embraced by the gemstone industry. However, caution must be exercised in cases where beryllium is infused during the heat treatment process, as it can have negative effects on the structural integrity and value of the stone.
| Mineral | Corundum |
|---|---|
| Colour Span | Light, pale yellow to an intense canary & orangish-yellow. |
| Popular Origins | Sri Lanka (Ceylon), Madagascar, Australia, Thailand, Myanmar (Burma) |
| Mohs Hardness | 9 (on a scale of 10) |
| Common Treatments | Thermal Enhancement |
| Birthstone | September |
Yellow Sapphires (Pukhraj) - A Quick Snapshot
6. Evaluating the Quality of a Yellow Sapphire
When evaluating the quality of a pukhraj stone, several factors come into play:
- Colour: The intensity, hue, and saturation of the yellow colour are taken into consideration while evaluating its quality. The ideal yellow sapphire exhibits a vibrant and pure yellow hue with uniform saturation, free from any undertones of brown or green.
- Clarity: Refers to the presence of inclusions like feathers and silk within the gemstone. While some inclusions are natural and expected, a high-quality yellow sapphire will have good transparency with minimal visible inclusions. In general, however, yellow sapphires contain fewer inclusions relative to blue sapphires and rubies.
- Cut: A well-cut yellow sapphire will maximize its brilliance, sparkle, and colour. Gem cutters aim to optimize the stone's shape, symmetric proportions, and facets to enhance its beauty and reflect light effectively.
- Carat Weight: Generally, a carat weight between 3 and 6 is considered standard, while a weight above 7 commands a size premium. It's important to note that carat weight alone does not determine a sapphire's quality and the overall quality should be considered in conjunction with the other factors.
- Origin: Yellow sapphires from certain regions, mainly Sri Lanka, are highly regarded for their exceptional quality and colour in comparison to other regions. However, countries like Madagascar and Myanmar also produce high-quality gems, although they are rarer.
To determine the overall quality of a yellow sapphire, it is important to work with a reputable jeweller or gemmologist who can assess the gemstone's characteristics and provide an expert opinion.
7. How Much Do Yellow Sapphires Cost?
Compared to blue sapphires, yellow sapphires are relatively more affordable, offering a wider price range. The cost of yellow sapphires can vary significantly depending on the aforementioned factors including its colour saturation, clarity, and overall rarity. Yellow sapphires with intense, vibrant hues and high clarity are generally more valuable and command higher prices.
Additionally, the origin of a pukhraj stone can also impact its cost. Thailand yellow sapphires, which are often infused with beryllium, are typically the least expensive variety. Their prices generally range between $100 and $300 per carat.
Sapphires from renowned sources like Sri Lanka which are known for producing exceptional yellow sapphires, may be priced higher due to their reputation for quality. Their prices can start at around $250 to $300 per carat and can soar to tens of thousands of dollars per carat for extraordinary gemstones. Burmese yellow sapphires, on the other hand, are usually cheaper compared to Sri Lankan sapphires and can range from around $100 to $700 per carat.
These price ranges are approximate and are influenced by the specific characteristics of each gem.
8. Yellow Sapphires in Astrology
In astrology, pukhraj stones are closely linked to the planet Jupiter, which is a symbol of wisdom, knowledge and prosperity. Yellow sapphires are particularly associated with the zodiac signs of Sagittarius and Pisces and are recognized as the birthstone for September.
In Vedic astrology, wearing a pukhraj is believed to attract the positive influences and blessings of Jupiter. Yellow sapphires are often referred to as the "wisdom stone" due to their association with wisdom and intellectual prowess. Beyond their symbolic representation of wisdom, yellow sapphires are also regarded as a symbol of prosperity and joy. Wearing a pukhraj stone is said to bring abundance and success in various aspects of life. It is believed to enhance one's financial prospects, promote happiness, and attract positive energies.
Yellow Sapphires (Pukhraj) in Astrology
In general, yellow sapphires are believed to offer a range of benefits:
- Prosperity & wealth: Yellow sapphires are associated with abundance and wearing this gemstone is thought to enhance one’s financial prospects.
- Spiritual growth & wisdom: Yellow sapphires are considered to be a stone of wisdom and spirituality. It is believed that wearing a yellow sapphire can enhance spiritual growth, promote clarity of thought, and stimulate intellectual abilities.
- Success & opportunity: Yellow sapphires are believed to bring opportunities and success in various endeavours. They are thought to enhance one's career prospects, promote leadership qualities, and open doors to new possibilities and achievements.
- Health & well-being: Pukhraj stones were historically believed to possess healing properties. In ancient times, they were used to treat snakebites and were known to detoxify the body. Today, yellow sapphires are considered energizers that promote vitality and strength.
