The 6th C of Sapphires: Curing

First, what do we mean by the term “curing”? Simply, the idea of Curing refers to the treatment of the gemstone. Specifically, Curing refers to the heating of the gemstone, usually with the aim of enhancing its properties and other attributes, under specific managed conditions. For those who are new to the concept, and to gemstone treatment in gemstone treatment in general, the term curing may seem like trying to “fix” a gemstone, possibly a defective one. This is a relevant consideration since, in relation to the idea of ‘Curing’ the gemstone, there is the more popular concept of ‘treatment’. A point which I shall get into. For now, what you need to understand is that the Curing of gemstones relates to the heating of the gemstone. However the emergence of the differences in the type of Curing, or the type of heating method that is undertaken. Here we will outline some of the key points you need to know when it comes to the treatment of the gemstone. Gemstones, like sapphires, that go into making quality engagement rings and other fine jewellery.

What is Meant by Curing?

One must understand that when it comes to the heat treatment of sapphires, the aim of the process is primarily to improve the colour of the gemstone. The ‘Curing’ that takes place in this form of treatment is that the innate characteristics of the stone are enhanced via the heating process. Since the sapphire in question contains natural properties that determine its value: the presence of colour, a limited number of inclusions, wider dispersion of colour in the sapphire, ability to reflect light etc. So the process of heat treatment, under carefully managed conditions, is meant to improve these preexisting qualities. It may surprise the reader to know that the curing (treatment of sapphires) via heating goes back thousands of years. Even the ancients realized then that the heating of the gemstone enhances its attributes. Thus one may encounter certain jewellers claiming that their gemstones have been subjected to “traditional” heat treatments. However, this is often where the confusion begins. For in more recent times the curing of sapphires has taken on different forms. A lot of them at best is not even ethical.

Differences between Curing and other types of Treatments

OK. Let’s get the terminology straight here. One of the reasons why we at Brilliyond developed the idea of the 6Cs, in this case, the 6th C of Curing, is to demarcate the lines when it comes to the process of how gemstones are treated. As noted, the idea of curing a sapphire comes under the broader category of gemstone treatment. However, the curing of sapphire is a particular process that necessarily excludes other forms of gemstone treatment. So in order to understand what is actually meant by the Curing of sapphire, we need to exclude other forms of sapphire treatment.

Curing Differs from Beryllium Treatment (Diffusion)

Beryllium treatment or beryllium diffusion refers to the process where gemstones (including sapphires), which in addition to subjecting to heat (at very higher temperatures), are then combined beryllium. Beryllium, to provide some information, is a chemical element (Be), which has a wide range of applications owing to its high conductivity, among its numerous other characteristics. At very high temperatures, the beryllium is able to seep through the crystal structure of the gemstone and affects its character. Where the chromophores (an aspect of a particle that determines its colour) are introduced from an external source. In this case, via the beryllium element. The logic behind this approach, as it is in any other types of sapphire treatment, is to enhance the properties of the stone.

Beryllium treatment necessarily involves the treatment of sapphires under tremendously high temperatures, which makes it conducive to combine it with the element beryllium. The extent of the beryllium penetration and its effect depends on the duration of the diffusion process. The longer diffusion of the sapphire, the deeper the colour penetrates. Beryllium treatment is used not only when it comes to sapphires but to other corundum minerals like rubies as well.

As one may have observed, the problem with this particular type of gemstone treatment is the addition of outside elements into the sapphire, to change or enhance its properties. The colour saturation or vividity, or the lack thereof, of the sapphire that has been treated, is not solely it's own. Hence its qualities carry an artificial character. Hence this process of sapphire treatment is not widely used, and in cases of such treatment, the gemstone is not considered as valuable or even legitimate. Usually, gemstones that have been subjected to beryllium diffusion treatment, need to be disclosed to the buyer in advance.

Curing Vs Irradiation

Another interesting type of gemstone treatment is irradiation. Unlike traditional heating of the sapphire, as one finds in the Curing process, irradiation involves the use of electromagnetic radiation to alter the gemstone’s (sapphire in this case) colour. Irradiation is a type of gemstone treatment that has been in use since the early part of the 20th century. And the application of irradiation has been used as a mechanism for adding colour to gemstones, including diamonds and pearls. The process by which irradiation changes colour involves the radiation disrupting the crystal’s atoms current structure, opening them to affected by external materials.

Gamma rays are the main type of radioactive source that is used in the irradiation of gemstones. This is due to the belief that gamma rays leave no residual radioactive effects behind, unlike radium for example, which is harmful to human health. So what does this type of gemstone treatment mean when it comes to Curing. Simply put, there are too many variables when it comes to gemstone irradiation. In addition to subjecting the gemstone to potentially harmful radiation; irradiated gemstones have effectively been altered at their atomic level. Meaning they no longer contain the same naturally occurring chemical character in the sapphire. So essentially there is no comparison between genuinely Cured sapphires, those that have been traditionally heat-treated and necessarily exclude this type of treatment, and those which have been diffused.

Other Forms of Sapphire Treatments

Dying

Dying is another type of gemstone treatment, which is usually adopted to improve the colour of the stone to a more popular hue. The exact methods of how gemstones like sapphires are dyed are varied, however, they are all united in their addition of external materials into the gemstone. Needless to say, this is a process that does not rely on the innate character of the stone, and instead seeks to modify its qualities. This is not a popular nor an acceptable form of treatment and can be easily identified by a good gemologist.

Glass-Filling

Glass filling generally refers to clarity enhancement, which as the name implies, is a process by which the clarity of the gemstone is enhanced by the addition of foreign materials, usually glass, to minimize some of the fissures that may be present in the gemstone. Which is typical in most naturally sourced gemstones. Since the ability to reflect light is one of the key characteristics that determine the quality of the gemstone, and the presence of fissures and other inconsistencies undermines it. So with glass-filling, the attempt is made to artificially rectify this. The problem here is if the gemstone, like a blue sapphire, has this many inclusions, and other shortcomings, it will usually be excluded from the gemstone selection process regarding jewellery.

Are Cured (Treated) Sapphires Artificial?

Simply No. As noted curing is a process that only applies to naturally sourced sapphires, with aim of enhancing its inherent properties and attributes. Artificial or synthetic sapphires, like other gemstone variants, are lab-grown copies of the natural gemstone. Whilst they contain the same chemical and crystalline character as natural sapphires, the process through which they are produced is, well artificial. It is sometimes understandable that the process of Curing a sapphire could be viewed as turning it into something artificial. In fact, certain sapphire companies (names which we shall not mention) have taken to position themselves (and the natural sapphires they sell) as authentic natural sapphires. The basis of this argument is that the non-treatment of a sapphire (i.e. a sapphire that has not been Cured) is the truly natural sapphire. There are a number of problems with this view.

All sapphires are in someways “Treated”

Think about it. Is there anything that we take from the natural world, that is automatically fit for consumer use? I mean fruits that are taken from trees, often need to be washed and cleaned. And when it comes to more durable resources like minerals, and fossil fuels, there is invariably a process of treatment: whether its the purifying, cutting, separating at the start. Then to more complex processes such as smelting, refining etc. When it comes to gemstones like sapphires and diamonds, these are subjected to a number of checking, verifying and cutting processes. Followed by polishing, shaping etc.

Curing is a form of Enhancing

The process of curing a sapphire is not to add artificial or external properties into it. Rather it is to improve and strengthen its existing qualities. The curing of the sapphire by following a traditional process of heating it under strict supervision enhances the gemstone. For in addition to the improvements to colour, the curing process also believed to strengthen the sapphire, making it more durable for long term use.