A ruby is what most often comes to mind when one thinks of a red gemstone. Though there are many other gemstones that display a red color, including red diamonds, there are properties that are exclusive to rubies. To begin with, a ruby is essentially a red sapphire, a gemstone of the corundum mineral variety. It can vary in color from pink to blood red, the color for which rubies are famous. The presence of chromium in the stone is the main cause for the red color. 'Ruber' in Latin means red, hence the name “ruby.” Considered one of the four precious gemstones, along with emeralds, sapphires, and diamonds, rubies are valuable, beautiful, and fascinating stones.
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2.06 ct Vivid Red Ruby |
Physical Traits
A ruby is an extremely strong stone. It ranks 9.0 on the Mohs scale of mineral hardness, placing it right after the diamond and moissanite. A diamond ranks 10.0 on the scale and moissanite falls in between diamonds and rubies. Like it or not, natural rubies contain imperfections, including color impurities. Additional imperfections are inclusions of rutile needles referred to as “silk.” These imperfections play an important role in detecting artificial rubies. Heat treatments are very common among most rubies today. Almost every ruby undergoes some sort of treatment, heat treatment being the most common. It is conducted prior to the cutting of the stone. That being said, there are a few high quality rubies that have not been treated, which of course demand very high prices.
A Ruby’s Color
Corundum that is considered gemstone quality and displays any shade of red or pink is considered a ruby. In the United States there are specific requirements regarding the saturation of a ruby. It must meet certain standards in order to fall into the ruby category, otherwise it is labeled a pink sapphire. The differentiation between the two types, rubies and pink sapphires, is a relatively new concept, having only been established sometime in the 20th century. That is why there is much controversy surrounding the topic.
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2.43 ct Vivid Red Ruby |
What Contributes to a Ruby’s Value
Like diamonds, rubies are assessed based on the 4Cs: color, clarity, cut, and carat. Similar to color diamonds, color is the most important determining factor in regards to its value. The darker and more visible colored rubies are the most sought after and the most expensive. Clarity plays an important role as well. Clear stones will sell for sky-high prices, but rubies without any needle-like rutile inclusions may signify that the stone has undergone treatment.
How Color is Graded
There are three aspects of a ruby’s color that are taken into consideration. These include hue, saturation, and tone. Hue refers to the ruby’s color as we see it. Saturation determines the visibility of the color. Is it light? Dark? Or somewhere in between? Finally, the tone tells us the purity of the color. If it is a pure tone, there will not be any secondary colors. If it is not a pure tone, it may include one or several secondary hues such as pink, purple, and orange.
As in most industries, there are attempts to replicate rubies artificially in order to have them pass as real ones. Many fall for this scam since the low prices are tempting. Purchasing synthetic rubies or treated ones is perfectly fine, as long as this is made clear beforehand. However, selling a fake ruby to an unassuming customer is wrong and illegal. Therefore, the proper homework must be done in order to obtain the ruby that is right for you.