Ruby Gemstone Information

Rubies are extremely hard and popular stones that can be created naturally or synthetically.

The ruby is a beautiful and popular gemstone that is classified as red corundum, meaning it is the crystallized form of aluminum oxide. Rubies are ranked second on the mineral hardness scale, with a hardness rating of 9. The only harder stone is a diamond. This makes the ruby a precious stone. Rubies are very popular due to their vivid color and beauty, but they are also one of the most expensive gemstones.

Colors

Rubies range from pink to blood red. Some rubies can also have a brownish or purplish tint. Rubies get their red color from the amount of chromium and iron in the stone. The best color for a ruby is called "Pigeon's Blood," and is a pure red color with just a slight hint of blue.

Locations

The majority of rubies are mined in Burma, Thailand, Sri Lanka and Tanzania. Though only 1 percent of the rubies mined in Burma are of gemstone quality, it is in this location that some of the Pigeon's Blood-colored rubies have been found. Rubies from Thailand tend to be more violet or brownish in color, whereas Sri Lankan rubies are a light or raspberry red. Tanzania also produces brownish and violet rubies. Rubies are mined in other locations such as south Asia and South Africa.

Grading Criteria

Rubies are graded like most other gemstones, using the 4 Cs: color, cut, clarity and carat. Color is ranked based on the saturation, hue and tone. Hue refers to the most common definition of color, tone is how light or dark the color is, and saturation is how vivid or bright the color is. Cut judges how the quality of the facets on the ruby help it reflect light, and clarity grades the number and type of the ruby's imperfections. Finally, carat refers to the size of the ruby. A large, naturally occurring ruby is more rare, and, therefore, increases the stone's value.

Treatments

There are a variety of treatments that can be done to improve a gemstone. A common treatment on natural rubies is the heat treatment. Rubies are heated to a temperature of about 1,700 degrees Celsius before they are cut. This process will improve the ruby's color and also its clarity. Rubies are also filled with synthetic glass if they have a crack or fissure that shows through on the surface.

Synthetic Rubies

Rubies can also be created in a laboratory. Synthetic rubies are sold in jewelry stores for a lower cost than natural rubies. Synthetic rubies are more clear than natural rubies, and don't create the natural flaws or color variations that real rubies do. Synthetic rubies are also used to make lasers and masers for scientific purposes.

References

• Gem Select: Ruby Gemstone Information