Sapphire Engagement Rings: Why Are Some Cheaper than Others?

Although sapphires form as a naturally occurring phenomenon of nature, they are often augmented through a series of processes that serve to enhance their clarity and colour. It is important to understand how these treatment processes work because the price of sapphires and sapphire engagement rings greatly depend on if they have been treated and to what extent.

Two of the more common ways to enhance sapphires include fracture filling and flux healing, and diffusion processes. This article outlines the fundamentals of both treatment practices so that you can be fully informed when shopping for sapphire engagement rings.

Fracture Filling and Flux Healing

Cavities and fractures within a gemstone can compromise its clarity by increasing the amount of inclusions on the inside of the stone. Many such sapphires in today’s sapphire engagement ring market have been heated and infused with a chemical flux in order to improve their clarity, shine and durability. At extremely high temperatures this flux penetrates the interior of the gemstone and settles into various fractures or cavities. When the gemstone is cooled, the chemical flux either solidifies into a glassy mass (fracture filling) or re-crystallizes as corundum within the cavity (flux healing).

There is considerable debate amongst expert gemmologists as to how much of the clarity enhancing effect is due to fracture filling versus flux healing. Either way, the treatment can make poor quality, low value sapphire engagement rings significantly more marketable.

Diffusion Processes

Diffusion processes, including both beryllium and titanium treatments, are relatively new treatment techniques that have sparked a large deal of controversy within the industry. While diffusion processes have many guises, they all revolve around heating a gemstone to very near its melting point while colour inducing elements are added to the interior of the stone. Titanium diffusion serves to add a strong layer of colour to the surface of a poorly coloured sapphire. However, because this type of diffusion process only enhances the surface colour of a sapphire, its original dull hue will be exposed if the stone on a sapphire engagement ring, for example, is chipped, nicked or re-polished.

More modern diffusion techniques use the element beryllium because of its more advantageous chemical makeup. Beryllium has a smaller atomic mass than titanium and as such it can penetrate deeper into the interior of a sapphire’s surface. Whereas titanium is used to induce blue coloured hues to palely shaded sapphires, beryllium is commonly used to colour sapphires with a more orange or golden tone.

Diffusion treatments are often applied as a last resort when heat treatments have failed to augment the colour of a sapphire. Gems that have obtained their colour from diffusion treatments have little intrinsic worth. Reputable dealers will identify diffusion-treated sapphires and offer them at prices well below those of natural, untreated stones.

Frederick Holm is staff writer for of the F&L Designer Guides, compiled and written to help consumers choose a unique engagement ring design. From a diamond to a sapphire engagement ring from a princess cut to a platinum band, we have ideas and opinions covering all the options. Offering advice, tips and suggestions on how to choose that perfect ring, F&L will accompany you on every stage of your search to find the right designer.