Red is associated with the most intense emotions, such as passion, love, and anger. We intuitively associate the color with power and desire—when someone wears a bright red lip shade or platform pump, or drives a fast red sports car.
The English word “ruby” was first recorded in 1300, but it originated from the Medieval Latin word rubīnus lapis or “red stone.” Rubīnus (lapis) is derived from the Latin word ruber or rubeus, meaning red.
Ruby gemstones have a rich history that dates back to ancient times. Past cultures prized the ruby gemstone—which they believed “held the power of life”—for its deep red hue resembling the color of blood flowing through our veins (GIA). In the Bible, the ruby symbolizes beauty and wisdom. In Sanskrit, one of the oldest languages, the word ruby or ratnaraj means “king of precious stones.” Literature about transports from the North Silk Road in China from 200BC recorded that rubies were carried westward from China along the ancient path. Australian historian Henry G. Smith wrote in 1896 that Hindu astrological beliefs regarded the ruby as the “gemstone of the Sun and also the heavenly deity Surya, the leader of the nine heavenly bodies.” Worshipping and wearing rubies was believed to cause the Sun to act favorably toward the wearer.
Physically, ruby gemstones are a type of mineral called corundum, which is composed of aluminum oxide. The red color of rubies is caused by the presence of a small amount of chromium. The intensity and saturation of the red color can vary depending on the location where the ruby is mined. While non-gem corundum can be found worldwide, ruby and sapphire gemstones are much rarer. Even though both sapphires and rubies are corundum, red corundum are rubies, and every other color of corundum are sapphires.
How to Grade Natural Rubies
Rubies are graded by cut, color, clarity, carat weight, and also geographic origin. Unlike diamonds, a ruby’s clarity, and intensity and saturation of color can vary depending on the location where it is mined. Each geographic location produces rubies with distinct qualities, chemical makeups, and inclusion patterns that can be used to identify a ruby's origin. For example, rubies mined in Thailand may have feather-like or tub-like liquid inclusions and flat, brownish cavities.
Rubies can also be graded using a system that categorizes gemstones from AAA to B. Only 1% of natural gemstones are grade AAA. 10% of gemstones are grade AA, and 20% are grade A; AA A graded gemstones are most commonly used in fine jewelry.
Ruby colors range from deep blackish red to orangish or pinkish red. While rubies can contain other secondary colors, the primary color must be red. The most valuable rubies have a pure red color, distinguished with a slight bluish tinge, that is traditionally called “pigeon’s blood” or Burmese red.
The Magok stone tract in Myanmar produces the world’s finest pigeon’s blood rubies. The gemstones occur at the byon layer, which is 20-100 feet deep. Miners uncover the stones using washed broad screens and handpicking the stones. While pigeon’s blood rubies most famously occur in Myanmar, they can also be found in Tanzania, Mozambique, and Vietnam.
Rubies a shade darker than pure red are considered wine color or “royal red” and have less sparkle than pigeon’s blood rubies due to their higher iron contents. Royal red rubies come from Mozambique, Thailand, Cambodia, Kenya, and Madagascar. Rubies also naturally occur in Pakistan, Sri Lanka, Afghanistan, India, Japan, Nepal, Australia, the United States, the Czech Republic, Finland, Greenland, Norway, Russia, and Namibia.
The ideal balance of tone and saturation is what really makes a ruby stand out. Saturation is the intensity, richness, and vividness of color. A ruby with low saturation has undertones of black, gray, and brown. Tone is the amount of color present in the ruby. An excess of color and a ruby will appear dark, opaque, and lifeless. Not enough color and the ruby will seem flat or glassy. A medium-toned, highly saturated ruby will produce the most sparkle, liveliness, and glow.
Opacity or clarity is graded on a scale from Very Very Slightly Included to Included (VVSI-I3). A ruby becomes more valuable as it approaches transparency, with no inclusions; a transparent ruby has the most vivid sparkle. A ruby with many inclusions can appear too dark and opaque or slightly pinkish. Additionally, a ruby can improperly reflect light and color if cut poorly, resulting in a lifeless or empty appearance.
Treatment of Rubies
The most common and widely accepted treatment for rubies is heat. Heat can permanently improve both color and clarity and diminish the appearance of inclusions. Other treatments for rubies are less permanent than heat, such as filling fractures and inclusions with molten lead. Untreated rubies with high color and clarity are pricier than their treated counterparts, but it is difficult to find an untreated, high-quality ruby over 3 carats.
Cleaning and Caring for Ruby Gemstones
Gems are graded on the Mohs hardness scale, which grades based on how easily one mineral can be scratched by another. While the scale grades from 1 to 10, the steps aren’t evenly dispersed. For example, corundum gemstones are a 9 on the scale, and diamonds are a 10 on the scale, but diamonds are many times harder than rubies and other gems in the corundum family. Regardless, the ruby has excellent toughness and is not easily broken when struck, so it is a great choice for everyday wear.
Rubies are considered “stable,” which means they are unaffected by coming into contact with heat, light, and common chemicals. Boric acid powder, however, can scratch the surface of an untreated stone. Lemon juice and other mild acids can damage fracture-filled and dyed ruby gemstones (GIA).
While fracture-filled and dyed stones should only be cleaned with a damp cloth, untreated, heat-treated, and lattice diffusion treated stones can be cleansed with warm, soapy water, ultrasonic cleaners, and steam cleaners.
Before cleaning your gemstone jewelry, make sure that the metal used to set the stone will not be damaged. Use caution when wearing or cleaning color-treated or fracture-treated stones since they can be damaged by a variety of chemicals and require a higher degree of care.
The glowing and vibrant ruby, the birthstone of July babies, is both enchanting in looks and history. Its durability and bold red color have stood the test of time, making it one of the most recognizable and valuable gemstones. From Dorothy’s ruby red slippers to the Richard Gere and Julia Roberts ruby necklace scene in Pretty Woman, the ruby will always exude luxury, passion, and power unmatched by any other gemstone.