Ruby: Introduction
Red is the color of love, passion, vivacity, exuberance, and power. It is also the color of one of the most beautiful gemstones in the world -the ruby. The ruby is known to be the July birthstone and is the stone given on the 15th and 40th marriage anniversaries to provide happy couples a long prosperous marriage. In ancient times the ruby is known as the "king of gems". The ruby has everything a precious stone would need- magnificent color, excellent hardness, and outstanding brilliance. The color of a ruby can range from fiery orange red to a deep purple red. Large rubies are hard to find, which make them rare, in some cases could be more valuable than a diamond of the same size.
Ruby: History
The ruby derives its name from the Latin word ruber which is a name that is based on its red color. Like many other gemstones the ruby has been used as a talisman to cure and protect. People in ancient times believed that rubies, if grounded into fine powder placed on the tip of the tongue were thought to have healing abilities for the blood as well as the heart. Many ancient cultures thought that wearing a ruby jewelry or under their skin will protect the user in battle. This is because of the ruby's blood-like color. The Hindus and Greeks believed that the ruby's color came from fire being trapped in the stone. They tried using rubies to boil water and even melt wax.
Famous Rubies
It is stated that flawless rubies mined from Burma are valued at millions of dollars. Although these mines generate outstanding rubies, it rarely generates rubies more than a few carats in weight. The Smithsonian's National Museum of Natural History in Washington carries the largest Burmese ruby known to date. The 23.1 carat, Burmese ruby called the Carmen Lucia ruby is set inside a platinum ring with diamonds, was donated by a businessman and philanthropist in memory of his wife.
The largest said ruby in the world is owned by the Beijing Fugui Tianshi Jewelry Co. Ltd. This ruby weighed in at 8184g (over 18 pounds) and measures in at 5.11 X 5.43 X 5.70 inches in size. Other notable rubies are the Edwardes ruby (167ct), which resides in the British Museum of Natural History, the Rosser Reeves star ruby (138.7ct), which resides in the Smithsonian Institution, and the De Long star ruby (100 ct) in the American Museum of Natural History.
Ruby: What is it made of?
Ruby is of the corundum species which consists of the ruby and sapphire. The corundum next to the diamond is one of the hardest substances on Earth. On the Moh's scale it registers as a 9, which comes second to diamond. Pure corundum is colorless and only red corundum can be considered as a ruby. All other color of corundum is considered a sapphire. Corundum is formed in igneous rocks that are relatively high in aluminum, but very low in silicon and in metamorphic environments with similar chemistry. In order for corundum to become a ruby, there must be certain minerals present in the rocks. Slight traces of elements such as chrome, iron, titanium or vanadium are responsible for the reddish color.
Ruby: Color
Just like emeralds, the ruby's color is the most dominant feature. The color of a ruby can range from fiery orange red to a deep purple red. As previously mentioned the ruby is of the corundum class and only red corundum can be classified as a ruby. All other colors are sapphire.
There are three components that a ruby is measured by. These are tone, hue, and saturation. The tone is a measure of the deepness of the red color. It describes whether the red is dark, medium, or light. Medium to medium-dark are considered the best tone of red. The hue describes the slight presence or hue of other colors. The basic hues of the ruby are: red, slight orange, strong orange, slight purple, and strong purple. And the saturation (also called the purity or intensity) describes how well the gem has been saturated with the red colors and how free it is from any brown or grey colors. Unlike diamonds which has different color-grading systems, rubies lack a convenient method to characterize their color. This is due to the extreme range of tone, hue, and saturation in rubies. Judging the best color is based on the "eye of the beholder". Most people believe that the rubies from the mines of Burma hold the greatest color of rubies. These rubies are called the Burmese Ruby or "Pigeons Blood" ruby.
Ruby: Cut
The best ruby cuts offer a depth/width ratio higher than comparable diamond cuts. These cuts are 65% - 80% for good quality rubies. If the ruby is cut too deep, it will make the stones look smaller than it is but it will show off more color than cut in normal proportions. These deep cut stones also preserve weight, increasing the cost of the stone. Stones that are too shallow will look bigger in weight will look larger than it is and will appear lighter in color.
It is hard find a perfectly cut ruby anywhere. This is because of two reasons. One reason that it is hard to find a perfect cut ruby is hard to find is that since rubies are so precious and rare; there is tentativeness to cut the necessary amount, during faceting process. Another reason why a perfect cut ruby is hard to find is that natural rubies when formed from the Earth's crust are shaped in an octahedral shape, which is usually wide and flat. This is why most ruby jewelry very shallow.
Ruby: Enhancements
Improving the quality of gemstones is common practice in the industry. The most common practice of ruby enhancement is heat treatment. Most, if not all rubies in the lower end markets are heat treated in order to enhance the color and remove the blue patches on it. Heat treatment used to be done with simple tools such as a blow-pipe and charcoal burner. Today heat treatment is done using chemicals such as beryllium, borax, lead and tantalum. The temperature for heat treatment reaches temperatures over 1800 degrees Celsius (3300 Fahrenheit). Occasionally, the stress from heat treatment used to enhance the color will create fractures over time and may need to be repaired.
Another process for enhancing rubies, which is a less acceptable method, is glass filling. This process is done by filling the fractures inside the ruby with lead glass, which will dramatically improve the transparency of the stone. If color needs to be added, glass powder with copper or other elements such as sodium, calcium, potassium, etc are treated with the ruby. Glassing filling, if done correctly can actually make the ruby more durable.
Ruby: Synthetic/Imitation
Because the ruby was so sought after, it was the first gemstone to be made artificially. The first ever documented attempt of synthetic ruby was made by French chemist Marc A. Gaudin. He created synthetic rubies by fusing aluminum at high temperatures and using chromium as a pigment. The first ever synthetic ruby was created in 1902 by another French chemist, Auguste Victor Louis Verneuil using the flame fusion process. The process was done by melting the ruby into fine powder using an oxygen-hydrogen flame and then crystallizing it into what is called a boule. This process is considered to be the founding step in modern crystal growth technology and is still widely used today. Rubies created using flame fusion are commonly used in bearings or mundane jewelry like high school class rings. Other processes of creating synthetic rubies are done by pulling process, flux process, and hydrothermal process. Flame fusion is more widely used compared to the other processes because of the low cost involved in processing.
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