How Are Rubies Processed?

Types

• There are several types of treatments for rubies that are meant to enhance their color and to raise their value. Most rubies on the market have undergone a heat treatment, which will stabilize their color and enhance their clarity. Some rubies may also have any problematic fissures injected with a molten solution of corundum and ruby, which is called filling. More rarely, rubies will also be exposed to high temperatures and coated with a thin layer of beryllium, a process which is called diffusing.

Effects

• The various processes used to enhance a ruby are meant to give it a deeper color or to make it more stable by sealing fissures in the gem. Heat treatment is permanent and it does not affect the durability of the stone. Filling a ruby will enhance its structure and prevent it from cracking further down the line, while diffusing a ruby will result in significantly deeper color.

History

• According to All About Gemstones, rubies have been processed to intensify their bright red or pink hues for more than 2,000 years. Though today it is done using materials like beryllium, lead, tantalum and borax, it was once accomplished using only blowpipes and charcoal braziers to heat the gem. The rubies of the Mong Hsu mine in Myanmar were thought to be useless for jewelry until the beginning of the 20th century, when a heat treatment was found that could reduce the purple or black core of these gems.

Identification

• An ethical gem vendor or jewelry vendor will be able to tell you what kind of processing has gone into a ruby, but there are some processes that you can detect yourself. Heat-treatment can be identified through the presence of bubbles in the filling of large fissures or a blue "flash" or tint that occasionally occurs. Diffusion is significantly more difficult to detect, and unreported diffusion in a gem is considered unethical.

Considerations

• Heat treatment is by far the most common process used to refine rubies. However, there has been an increasing demand for natural rubies, which refers to rubies that have been only cut, polished and cleaned. These rubies are considerably more expensive than rubies that have been treated, but identifying them can be difficult. If you are interested in purchasing a natural ruby, make sure that you go to a highly reputable dealer.