Ruby, a heart's desire...

Amelia L. Hess


  • Introduction
  • Ruby Facts
  • Synthetic Rubies
  • Treated Rubies
  • Ruby History & Lore
  • Famous Rubies
  • Buying Rubies
  • Ruby Mining
  • Ruby Confusions
  • Caring for your Rubies
  • References
  • Image taken from R.F. Moeller Jeweler


    Rubies are known for being the birthstone for July and are one of the most prized gemstones. Ruby is also used as the stone for 15th and 40th marriage anniversaries. Rubies are known for their hardness, durability, luster, and rarity. Large rubies are hard to find and are therefore more valuable than diamonds of the same size.

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    Ruby Facts

    Moh's Hardness9
    Density3.97 - 4.05
    Fracturesmall conchoidal, splintery, brittle
    Crystal Systemtrigonal
    Chemical Composition Al2O3
    Transparencytransparent to opaque
    Refractive Index1.762 - 1.778
    Double refraction0.008 - 0.009
    Pleochroismstrong; yellow-red, deep carmine red
    Fluorescencestrong: carmine red
    ColorVarying shades of red

    Rubies often have inclusions which are sometimes removed by heating. Inclusions of tiny parallel Rutile needles causes a asterism effect in polished rubies. These rubies are known as star rubies and often show six ray stars and occasionally twelve ray stars.

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    Treated Rubies

    Heat treatment, dyeing, and oiling of rubies are common practices. Heat treatment is usually done to the rough stone to improve color and clarity. Often a catalyst, such as borax, is used to fill in natural fractures in the gemstones. Star rubies are not heat treated. Heat treatment would destroy the rutile needles that cause the asterism in the stone. Oiling and dyeing is usually done to lower quality stones and is not permanent. These treatments are not considered deceptive unless you are not told that the treatment was done.

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    Synthetic rubies

    Synthetic rubies (lab-created) are real rubies as far as their chemical properties are concerned. Because they are made in a laboratory instead of by nature, they are not considered natural. Some of the inclusions may be different between natural rubies and synthetics. It may take a trained gemologist to be able to tell if the ruby is lab-created or natural. Rubies were first synthesized in 1902 with a process known as the Verneuil process. There are several different ways to create rubies. One method is the flame-fusion process. This process is fairly inexpensive and can produce rubies in a few hours. The melted ingredients are dripped into a boule and are then allowed to cool at room temperature and pressure to crystallize. They are not of a very good quality and are often found in costume jewelry, class rings, and lower priced jewelry. Another method is the flux-growth process. This process takes much longer and can produce rubies that are difficult to distinguish from natural rubies. The ingredients are melted into a flux (molten chemical) and are then crystallized under restricted conditions. This process may take many months to complete. A company that is well known for its flux produced rubies is Chatham. Chatham began producing flux rubies in 1958 and were the first company to do so worldwide. Other synthetic rubies include Douros from Greece, Kashan, Chakravorty, and Ramaura.

    From left to right: Chakrovorty™ Synthetic Ruby Crystal, Kashan™ Synthetic Ruby Crystal,
    Faceted Synthetic Rubies, and Flame Fusion Boule Synthetic Rubies.
    Images taken from Roger K. Pabian's July Birthstone - Ruby

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    Ruby History & Lore

    Ruby was named for the Latin word 'ruber' which means red. Ruby's day is said to be Tuesday, its season summer, and its apostle St. Matthew. Eastern legends believe that rubies contain the spark of life "a deep drop of the heart's blood of Mother Earth." Some ancient Orientals believed that the ruby is self-luminous and called it "glowing stone" or "lamp stone." It is believed that the Emperor of China used a ruby to light his chamber. Hindu priests believed that the homes of the gods were lighted by emeralds and rubies. Greek legends also speak of ruby. It was said that a female stork repaid Heraclea for her kindness by bringing her a ruby so bright that it illuminated her room at night. Ancient Hindus, Burmese, and Ceylonese believed that rubies ripen with age. The believed that sapphires were unripe rubies and that inclusions in stones meant that they were overripe. Rubies were thought to bring good health, guard against wicked thoughts, amorous desires, and disputes during the Middle Ages. Red stones including rubies were thought to cure bleedings. A stone which turned darker was thought to warn its owner of coming misfortunes, illness, or death.

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    Famous Rubies

    The Edwardes Ruby (167 carats) was named for Major General Sir Herbert Benjamin Edwardes who helped save British rule during the years of mutiny in India. It was donated to the British Museum of Natural History in London by John Ruskin in 1887. The Rosser Reeves star ruby (138.7 carats) is considered to be the largest fine star ruby in existance and was insured for $150,000 in 1966. It is located in the Smithsonian Institution in Washington, D.C. The De Long star ruby (100 carats) is a oval cabochon which is located in The American Museum of Natural Hisotry in New York. It was purchased by Edith Haggin DeLong from Martin Ehrmann for $21,400. The Peace Ruby (43 carats uncut) is a 25 carat faceted round brillitant. The Anne of Brittany Ruby (105 carats) is a polished but irregular gem and is housed in the Louvre in Paris.

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    Buying Rubies

    The four c's (color, cut, clarity, and carat) are still in effect for buying rubies. Cut is of course your choice. Rubies often are cut as ovals or cushion-cuts, but many others are available. Clarity is less strict with rubies than stone such as diamonds. All rubies are expected to have inclusions of some find. If you find a ruby that is flawless, most likely it is not a ruby. Ask to look at the ruby through a loupe before buying. Make sure the inclusions are not enough to threaten the strength of the stone. Fractures that come to the surface of the stone could be a risk. If inclusions are so numerous that the stone is cloudy or opaque you may want to avoid the stone. Color is one of the most important factors with ruby. The richer and deeper the color the more valuable it is. Of course as with cut the final choice is your personal preference. Be sure that you know if the gem is natural or synthetic and also if it has been treated. This will make a difference in the price of the piece.

    Natural Rubies, Sri Lanka
    Image taken from Roger K. Pabian's July Birthstone - Ruby

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    Ruby Mining

    Host rocks of rubies often include metamorphic dolomite marbles, gneiss, and amphibolite. However, rubies are not normally mined from the primary deposits due to the high cost of mining. They are mined from the secondary deposits which are usually alluvial. Mining of rubies is still fairly primitive and takes many man-hours of labor to find the rubies. Once the gem bearing alluvial material is found then the gravel is sifted through wire screens and picked out by hand. Many countries are producers of rubies. The most well known deposits are in Burma (Myanmar), Thailand, Sri Lanka, and Tanzania. Other areas where rubies are found include: Afghanistan, Australia, Brazil, Cambodia, India, Kenya, Madagascar, Malawi, Nepal, Pakistan, United States, Vietnam, and Zimbabwe. The Mogok valley of Burma is best know for the finest and rerest rubies known as "pigeon's blood" for the intense red color. Thailand is well known for it's dark, brownish-red rubies.

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    Ruby Confusion

    Until about 1800 all red gemstones were called rubies. Later this changed and many stones which were thought to be rubies were in fact red spinel, red tourmaline, and red garnet. An example of this is the "Black Prince's ruby" in the English State crown that was thought to be a ruby, but in fact is red spinel. Below is a table listing some names of confusions often associated with rubies.

    False Gemstone NameGemnological Name
    Adelaide Rubypyrope garnet
    Alabandine Rubyalmandine garnet
    American Rubypyrope garnet
    Ancona Rubyrose quartz
    Arizona Rubypyrope garnet
    Australian Rubypyrope garnet
    Balas Rubypink to pale red spinel
    Bohemian Rubypyrope garnet
    Brazilian Rubypink topaz
    California Rubypyrope garnet
    Cape Rubypyrope garnet
    Colorado Rubypyrope garnet
    Copper Rubycuprite
    Elie Rubypyrope garnet
    Garnet Rubygarnet
    Geneva Rubysynthetic ruby
    Montana Rubypyrope garnet
    Rocky Mountain Rubypyrope garnet
    Ruby Spinelred spinel
    Siberian Rubyred tourmaline
    Spinel Rubyred spinel

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    Caring for your rubies

    Rubies are durable and are fairly easy to clean. Wipe your ruby jewelry with a soft cloth to remove dirt and residues. An ultrasonic cleaner can be used if the gemstone does not have too many inclusions. Rubies can be soaked in alcohol, vodka, or one part ammonia to six parts water to loosen dirt. After cleaning it can be rinsed and brushed with a soft brush. Do not use abrasives on rubies. Abrasives will not hurt the ruby but may scratch the settings. When not wearing your rubies store them in a jewelry case or in a soft cloth. Be sure that the gemstones do not rub together to prevent scratching. Normal wear can eventually loosen prongs and settings. Have your jewelry checked by a professional to ensure that the settings are still in good condition.

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    Return to the top or the GO 340 Student Webpage Index.

    This web page was created by Amelia L. Hess as a student project for GO340 Gemstones and Gemology at Emporia State University for the Spring 2003 semester.