Natural gemstones have long captivated mankind with their stunning beauty and mystic allure, but the very phrase “natural” in this context comes with a somewhat complex connotation. This connotation is that any gemstone that has undergone a treatment – irrespective of whether this treatment is favourable or unfavourable, cannot be deemed “natural”. This is certainly true in certain instances, such as for glass-filled rubies, which are infused with lead-glass that changes the chemical composition of the stone altogether. But in most other instances, such as thermal enhancements (a widely accepted industry practice), the treatment does not alter or hamper a gemstone’s structural integrity or durability, and the gemstone can still be considered “natural“. In this blog post, we aim to debunk this myth and shed light on the truth – that most mined gemstones, including those subjected to thermal enhancements, can indeed be deemed “natural”.
An IGI Report of a Blue Sapphire - clearly indicating that the stone represented is a “Natural” corundum, even though it has “Indications of heating”
As a rule of thumb, it’s good to understand that anything that nature creates on its own, without human intervention is “natural”. In this sense, every fruit or vegetable, such as a potato which is grown by a farmer using fertilizers and water sprinklers is as “natural” as a potato that has grown in the wild without the intervention of a farmer. The only difference is that a farmer-grown potato is more suited toward human needs and consumption, whereas the wild potato may not be instantly consumable. Indeed, this is analogous to the world of gemstones as well.
Thermal enhancement, a widely practised gemstone treatment, involves carefully controlled heating to improve a gemstone’s characteristics without compromising its longevity or authenticity. It is an accepted practice within the industry, aimed at enhancing the inherent beauty of gemstones. A simple thermal enhancement or “heat treatment” helps to bring out the natural colours of a gemstone more vividly and also enhances its transparency – making it more suitable for both, astrological and jewellery purposes.
In this piece, we dispel the misconceptions that surround the term “natural” gemstones and explore the remarkable journey that combines the wonders of nature with the skilful techniques employed by experts, resulting in exquisite treasures that captivate the eye.
Natural v. Synthetic v. Fake Gemstones - What’s the Difference?
Before we delve into the world of thermal enhancement, it is essential to clarify the meaning of the term "natural" in the context of gemstones. As specified above, any gemstone that has been formed by geological processes under the surface of the earth over millions of years can be deemed “natural”. Natural gemstones are cherished for their unique characteristics and rarity; however, it is crucial to note that the natural formation of a gemstone does not necessarily imply that it remains unaltered from its original state throughout its existence. This is where thermal enhancements and other treatments come into the picture – as discussed in subsequent sections of this article.
Synthetic gemstones or lab-made stones are those that have been synthesised in laboratories. These gemstones are chemically identical to their natural counterparts, but have been produced in controlled environments using seeds of natural gemstones. CVD diamonds (Chemical Vapour Deposition) are perhaps the most popular examples – which are lab-grown diamonds that are created in controlled environments that mimic natural geological processes. Although these gemstones are not “fake”, they are not natural either, and are not intrinsically rare (since there can be a virtually unlimited production for them), as opposed to their natural counterparts.
Diamond seeds used in the CVD process to create lab-grown diamonds
Finally, “fake” gemstones are simply crystals that are passed off as authentic gemstones. These are usually designed to resemble a natural gemstone but are not chemically or structurally identical to them. Generally, such gemstones are created in laboratories or factories using various materials and processes to mimic the appearance of genuine gemstones, and are passed off to consumers as such. For example, red spinels are often sold as rubies by unethical traders – this makes the spinel (which by itself may be a real spinel) a “fake” ruby. It's important to note that the use of fake gemstones is not necessarily deceptive or unethical, as long as they are properly disclosed and sold at appropriate prices. However, misrepresenting synthetic or simulated gemstones as natural gemstones is fraudulent.
Understanding Thermal Enhancements - a.k.a. Heat Treatments
Thermal enhancement, commonly known as heat treatment, is a widely practised technique in the gemstone industry. It involves subjecting gemstones to controlled heating processes to enhance their colour, clarity, and overall appearance. By replicating the natural geological conditions that gemstones undergo deep within the Earth, thermal enhancement unlocks the full potential of these precious stones, resulting in a more vibrant and desirable final product. Through precise temperature ranges and durations, gemstone experts can eliminate or alter colour-producing impurities, intensify the gem's hue, and improve its transparency by dissolving internal inclusions and imperfections. The result is an array of mesmerizing gemstone colours and heightened clarity that captivate the beholder's eye.
The benefits of thermal enhancement extend beyond individual enhancements, as it optimizes the overall appearance of gemstones. Gemstone experts carefully balance the application of heat to unlock the hidden potential of each stone while ensuring its integrity is maintained. This delicate control of the thermal enhancement process results in gemstones that showcase their innate charm and maximize their visual appeal. Whether it's intensifying the colour of a gemstone, improving its clarity, or refining its transparency, thermal enhancement allows these treasures to shine with unparalleled beauty.
Low-temperature heating of a Mozambique Ruby (Source: GIA)
In general, a majority of the sapphires, rubies, spinels, tanzanites and similar gemstones available in the market today, are thermally enhanced or “heated”. This is acceptable since this treatment doesn’t harm the structural integrity or the durability of the stone in any shape or form. As long as sellers disclose this treatment to their consumers and do not pass them off as “untreated” – consumers can use these gemstones without worry.
Simple thermal enhancements or heating of a gemstone, in the sense described above, do not pose a problem. The problem arises when certain manufacturers diffuse other elements (such as beryllium) into a gemstone during the heating process. The introduction of such a foreign element into the composition of a gemstone enhances its colours, but also hampers its overall structural integrity. This results in a cheaper, but better-looking gemstone, and over time, the compromised structural integrity may lead to issues such as increased susceptibility to damage, colour fading, or even complete structural failure. This introduction of a foreign element into the crystal structure of a gemstone also alters its chemical composition – making for an inferior-quality product.
The essential takeaway here is that a stone that has undergone a simple thermal enhancement can still be deemed natural. However, when an alteration takes place in its structural integrity due to human intervention or the introduction of a foreign element within its crystal structure, it is instantly classified as “treated” or a hybrid. This means that the extent to which a stone is altered determines whether or not the stone can be considered “natural”.
Why a Simple Thermal Enhancement is Accepted Industry-Wide
Thermal enhancement, despite facing criticism from certain purists, is widely accepted within the gemstone industry for several compelling reasons. Reputable gemmological institutions acknowledge and embrace thermal enhancement as a legitimate practice, thereby establishing its credibility. The transparency surrounding thermal enhancement is a key factor in its acceptance. Unlike undisclosed treatments or enhancements, thermal enhancement is openly disclosed in the gemstone trade, ensuring that buyers are aware of the treatment applied to the gemstones they purchase. This transparency allows consumers to make informed decisions based on their preferences and understanding of the gemstone's characteristics. It also promotes trust and confidence in the gemstone market, fostering a fair and ethical trade environment. Additionally, it is essential to note that thermal enhancement does not compromise a gemstone's longevity or durability. When performed correctly, the controlled heating processes involved in thermal enhancement do not harm the gemstone's structural integrity, ensuring that the enhanced gemstone can withstand the test of time.
A 26-carat Tanzanite before & after heat treatment. Almost all Tanzanites available in the market today are thermally enhanced.
The acceptance of thermal enhancement within the gemstone industry is also attributed to its positive impact on gemstone affordability and accessibility. By subjecting gemstones to thermal enhancement, manufacturers can enhance the colours and overall appearance of gemstones, making them more visually appealing. This process often results in gemstones that possess vibrant and desirable qualities, comparable to their rarer and more expensive natural counterparts. As a result, consumers can acquire gemstones with enhanced aesthetics at a lower cost, allowing a broader range of individuals to enjoy the beauty and elegance of gemstone jewelry. This affordability and accessibility contribute to the popularity and widespread acceptance of thermal enhancement in the industry. Furthermore, with proper disclosure of the treatment, buyers can make informed choices based on their budget and personal preferences, creating a more inclusive and diverse market for gemstones.
Transparency & Honesty
In the gemstones trade particularly, maintaining integrity on the part of sellers is vital, since most consumers purchasing gemstones aren’t fully aware of the intricacies involved in the production or formation of a gemstone. Sellers should not only educate the consumer about their choice of gemstones, but also disclose any and all treatments that a specimen might have undergone. By openly disclosing these treatments, sellers uphold ethical practices and establish credibility with buyers. Complete transparency empowers consumers to make well-informed decisions aligned with their personal preferences and values. Trust is fostered when sellers prioritize transparency, ensuring buyers have access to all relevant information when considering a gemstone purchase.
Consumers hold the right to be fully informed about the treatments applied to gemstones they intend to purchase. Disclosure of treatments, such as thermal enhancement, allows buyers to evaluate the characteristics and value of a gemstone accurately. With this knowledge, consumers can make informed choices based on their preferences, ethical considerations, and investment goals. By embracing transparent disclosure, sellers contribute to a fair and trustworthy gemstone market, where buyers can confidently select gemstones tailored to their individual needs and values. Open communication fosters a sense of transparency, building strong relationships between buyers and sellers in the gemstone industry.
In conclusion, the term "natural" should not be limited to completely untreated gemstones. All mined gemstones are natural, regardless of whether they have undergone thermal enhancement or not. Thermal enhancement is a legitimate practice that enhances the beauty of gemstones while preserving their longevity. By openly disclosing treatments, the gemstone industry ensures transparency and empowers buyers to make informed choices.
