Ruby is the birthstone for July and the gem for the 15th and 40th anniversaries.
Ruby can command the highest per-carat price of any colored stone, making it one of the most important gems in the colored stone market. In its purest form, the mineral corundum is colorless. Trace elements such as Chromium become part of the mineral’s crystal structure cause ruby’s red color. The strength of ruby’s red depends on how much chromium is present—the more chromium, the stronger the red color. Chromium can also cause fluorescence, which adds to the intensity of the red color.
Red is the color of our most intense emotions—love and anger, passion and fury. It’s associated with objects of power and desire—like fast cars and red roses. Early cultures treasured rubies for their similarity to the redness of the blood that flowed through their veins, and believed that rubies held the power of life.
Ruby is one of the most historically significant colored stones. Rubies are mentioned four times in the Bible, in association with attributes like beauty and wisdom. In the ancient language of Sanskrit, ruby is called ratnaraj, or “king of precious stones.” Ruby has been called the most precious of the 12 stones created by God.
Desire for ruby is just as great today as it always has been. As a symbol of passion, ruby makes an ideal romantic gift. Consumers are drawn to the lush color because it also signifies wealth and success.
Color is the most important quality factor for ruby
The finest ruby has a pure, vibrant red to slightly purplish red color. As the color becomes too orangy or more purplish, the ruby moves down in quality. The highest-quality rubies have vivid color saturation. The color must be neither too dark nor too light to be considered finest quality.
People in the trade expect rubies to have at least some inclusions because inclusion-free rubies are rare. Ruby value depends on how visible the inclusions are. Obvious inclusions or inclusions that reduce transparency or brightness lower a ruby’s value dramatically.
Several factors affect the cut and proportion of rubies on the market. A ruby’s crystal shape dictates its suitability for certain cuts. The most common shape is a flat tabular hexagonal shape, but ruby crystals from some sources can be elongated.
Fine-quality rubies over one carat are very rare, but commercial-quality rubies are commonly available in a wide range of sizes. The price per carat goes up significantly for ruby as it increases in size.
TIPS & ADVICE
- Work with a jeweler you trust.
Judging the quality of ruby requires expertise. Look for gemological credentials. A jeweler who knows and loves ruby will have several to show you so you can see quality differences side by side.
- Don’t confuse origin with quality.
Even the best mines produce low-quality material. Where a ruby comes from is no guarantee of value or quality. Fine-quality rubies can come today from several countries.
- Ask about treatment.
Most rubies have been heated, and some gems on the market also have had color diffused into the surface or fractures filled with lead glass to improve their appearance. When shopping, ask about treatment information included in writing.
- When in doubt, get a lab report.
A report from an independent laboratory like GIA can confirm that the ruby you are buying is natural and tell you whether there is evidence of treatment.
- CHEMICAL COMPOSITION:Al2O3
- REFRACTIVE INDEX:762 to 1.770
- BIREFRINGENCE:008 to 0.010
- SPECIFIC GRAVITY:00 (+/- 0.05)
- MOHS HARDNESS:9
(Gem Encyclopedia Ruby)