Ruby colors
Buying Ruby
Where is Ruby found?
Common Ruby Treatments
World-famous Ruby
Ruby gemology
Ruby legends & lore

Ruby colors
Rubies range in color from pinkish to orangey and purplish and brownish red, depending on the chromium and iron content of the stone. The most desirable color is the so-called "pigeon's blood", a pure red with a hint of blue. The distribution of color is often uneven, in strips or spots.

Buying Ruby
Color is the most important consideration, with clarity a distant second. Large rubies are rare.

Color
The most desirable color is the so-called "pigeon's blood", a pure red with a hint of blue. Color saturation makes all the difference.

Lighting
Ruby shows pleochroism which means that the color varies with the direction of viewing. Cat's eye effect, silk sheen and six-rayed-star light effect shimmer best over the surface of the stone when moved in daylight.

Many rubies will fluoresce in long or short wave UV and this property can often be used to help identify a stone's geographic origin. Burmese rubies often fluoresce so strongly that the effect is noticeable even in sunlight, such stones seem literally to glow, and are greatly admired. Thai stones generally lack this property.

Clarity
Inclusions are common and not always an indication for lower quality. Included rutile needles cause the "silky shine". If such a stone is cut en cabochon it exposes the rare cat's eye effect. Oriented rutile crystal inclusions cause a six-rayed-star light effect (called asterism) to form the popular star ruby.

Cut
Transparent rubies are cut in step and brilliant cut. Less transparent rubies are cut en cabochon.

Ruby location and deposits
Myanmar: For centuries the most important deposits are in upper Myanmar (Burma) near Mogok. Only one percent of the production is of gem quality. Some of the rubies are of pigeon's blood color and considered to be the most valuable rubies of all. In the early 1990's large new deposits were discovered at Mong Hsu.

Thailand: Rubies found in Thailand (Chanthaburi district) often have a brown or violet tint. The Thai ruby production is declining, and Chanthaburi is now mainly a center for processing and trading gems.

Sri Lanka: The deposits are located in the southwest of the island in the Ratnapura district. Rubies from that deposits are usually light red to raspberry red.

Tanzania: On the upper Umba River in northwest Tanzania are deposits for gemstone quality rubies that are violet to brown-red. A few opaque rubies are mined as well.

Further deposits of importance are found in: Afghanistan, Cambodia, Kenya, Madagascar and Vietnam. Less important deposits are in: Australia, Brazil, India, Malawi, Nepal, Pakistan, United States and Zimbabwe.

Common Ruby treatments
The most common treatment for ruby is heat treatment. Stones, generally before they are cut, are heated to between 1700 to 1800 degrees Celsius (3100-3300 degrees F) for several hours. That is just a continuation of how nature made the gemstone itself, by massive amounts of high heat. Heating improves tone and saturation of the color. A reputable dealer should always tell if a stone has been subject to heating.

Diffusion treatment exposes the surface of the stone to certain chemicals combined with heat. Generally, only the surface color changes, while the stone's body remains as is. That effect is not very desirable.
The only exception as a acceptable treatment applies for the star ruby. The diffusion is done on the surface of the ruby and could extend to around a millimeter into the stone. That process supports the star effect on the gemstone. The hardness of the gemstone is not affected by the diffusion treatment.
Occasionally fractures of a ruby are filled with polymer or glass.

World-famous Ruby
The largest ruby that could be cut weighted 400 ct, was found in Myanmar and divided in three parts.
Famous stones of outstanding beauty and color are the "Edwardes Ruby". weight 167 ct, showed at the British Museum of Natural History in London, the "Rosser Reeves Star Ruby", of 138.7 ct, to be seen at the Smithsonian Institution in Washington, the "De Long Star Ruby", weight 100 ct, shown in the American Museum of Natural History in New York and the "Peace Ruby", 43 ct, which was found after World War I in 1919.

Many rubies are an essential part of royal insignia and other famous jewelry. The Bohemian St. Wenzel's Crown holds an unfaceted ruby of about 250 ct.

Some famous large rubies, such as the "Black Prince's Ruby" and the "Timur Ruby" in the British Crown Jewels are actually spinels, because until the beginning of the 19th century red garnets or spinels were thought to be rubies. A similar down grading experienced the Crown of the Wittelbachs from 1830, which's drop-shaped spinels were thought to be rubies.

Rubies are forever one of the favorite gems for the rich and famous. Elizabeth Taylor owns a spectacular ruby necklace and earring set. During an auction of the estate of Jacqueline Kennedy Onassis by Sotheby's on April 24, 1996, a spectacular 17.68-carat ruby ring sold for $290,000; some cabochon ruby dangling earrings sold for $360,000; and a cabochon ruby necklace was a bargain at $247,500. Marlene Dietrich owned a ruby bracelet that sold at Sotheby's for $990,000.

Rubies have also a famous place in science - the first lasers were made from artificial ruby crystals.

Ruby gemology
Species: Corundum
Color: Varying red
Chemical composition: Al2O3 aluminum oxide
Crystal system: (Trigonal) hexagonal prisms or tables, rhombohedrons
Hardness: 9 (Mohs scale)
Specific gravity: 3.97 - 4.05
Refractive index: 1.762 -1.778
Birefringence: -0.008
Color of streak: White,
Absorption spectrum: 694, 693, 668, 659, 610-500, 476, 475, 468
Fluorescence: Strong carmine red

The Ruby zodiac, myth & legend
For a long time India was considered as the classical country of rubies. In the Sanskrit language ruby is called "ratnaraj", which does translate as "King of Gemstones".

In ancient times one of the chief attractions of ruby has been its protection from misfortune and bad health.
Ruby is the birthstone for those who are born in July. On the Zodiac chart, ruby is the stone for Capricorn.

Ruby is also used to celebrate a couple's 15th and 40th anniversary.

In Antiquity, as well as in the Middle Ages people believed that the cosmos is reflected in gemstones. The ruby is assigned to the planets Mars and Pluto. The esoteric movement revived the ancient belief and the gem industry made it another marketing tool to promote certain gems.

The healing powers of gems remain a controversial issue, but are mentioned for centuries by healers, shamans and medicine men. Whether it's a fact or a placebo effect doesn't matter, if it helps. The safest approach is to wear the gemstone in skin contact to the troubled part of the body. Ruby is said to be a general health protection and a helper for backache and toenail problems.