Refining Rubies

There are a number of ways to treat rubies to improve their color, clarity and ultimately, their value. The quick fix method is to dye or oil the ruby which will help hide fractures, inclusions and improve the color of the stone.

A further refinement of this is a diffusion process where stones are immersed in a chemical bath which contains a number of chemicals including chromium which gives the ruby its color in the first place. This color is carried in the skin of the ruby by the chemicals and actually penetrates the skin. This generally produces a light tone and the tone is only a skin which will disappear upon re-polishing.

The next common treatment is a heat treatment. Rubies stand heat far better than emeralds do and it is fairly common to heat both rubies and sapphires which tends to improve the color by driving out bluish or brownish tints and will tend to dissolve the transparency, lessening the "silk" inclusions on heavily included stones.

These treatments all are dependent upon temperature, time and cooling rate, but they will bring about a permanent change in the stone leaving no chemicals or treatment to be removed.

In top ratings, rubies are rarer than diamonds but the actual supply of top stones may vary greatly because of political situations. Many stones reach the world markets because they have been smuggled out of places (especially Burma) through Thailand and other friendlier countries. There is a fair amount of profit to be made in the smuggling of rubies.

Smaller, included or industrial strength stones, are cheaper than their diamond cousins because they are more easily available.

The rhodolite garnet often approaches ruby in color, although tends to be more purplish than the ruby and less saturated but still are sometimes sold as rubies.

Tourmaline also occurs in many color ranges including red ruby and is sometimes sold as ruby.

A new stone called red spinel has a remarkable resemblance to ruby and is not often seen on the market because it is generally sold as a ruby.

Rubies have been synthesized since the late 1800s. There are two primary methods of synthesizing rubies - the fusion method and the pulling method. In the 1950s, several manufacturers began flux growing rubies which takes considerably longer than the other methods and produces a stone much closer to its natural version.  Flux grown rubies tend to be extremely clear and transparent with an orange overtone.

Fusion stones tend to be strikingly flawless looking while the flux methods may actually produce a number of inclusions resembling silk.

One clue to synthetic rubies is the cut. Because the material is cheaper and waste is not as much a problem, machine cuts such as square or rectangular cuts are more prevalent.