If you were born in July, you’re lucky enough to have ruby as your birthstone! Rubies are precious gemstones, capable of commanding some of the highest prices for colored gemstones. This durable and beautiful red stone has been treasured for millenia, and the appeal endures.
Red Sapphires?
Rubies are red gemstones composed of the mineral corundum. In other colors (notably blue, but also green, yellow, orange, violet, black, and white), gem-quality corundum is called sapphire, but the “red sapphires” get their own designation. Today, gemologists identify stones based on their chemical composition using special tools to identify the mineral makeup of a stone. For rubies and sapphires, the chemical corundum (a type of aluminum oxide) is the main mineral; trace elements are responsible for the different colors that can be found in the sapphire and ruby spectrum. In rubies, chromium is the mineral that causes the red color (which is unique among red gems, which often get their red color from iron, which gives a ruddier, rustier red color than the vibrant red of ruby).
Why? The truth is that gems have been mined, cut, traded, valued, and admired for thousands of years, but until relatively recently, the classification of different gems was more of a visual and less of a scientific process. Instead of grouping gems together based on their chemical composition (ie. all minerals in the corundum family having one trade name), gems were identified by their color and general appearance. Until the scientific advances that came with the Enlightenment Era, if it was a pretty red gemstone, they were going to call it a ruby. This practice led to some interesting cases of mistaken identity, most notably with several famous “rubies” turning out to be spinels.
Even though gemologists identify stones based on their chemical composition today, there is still some subjectivity to determining what constitutes a ruby. The difference between a dark pink sapphire and a ruby is in the eye of the beholder– both are corundum, both have the same refractive index, but the line between dark pink and red is often a matter of personal or cultural opinion.
In this one-of-a-kind engagement ring by Secrete Fine Jewelry, rubies increase in size in a crescendo to compliment the center diamond in this engagement ring. Rubies are perfect for this colorful engagement ring for the fire of their color and for their durability.
The King of Gems
The Sanskrit word for ruby is ratnaraj, or “king of gems.” The beautiful, glowing red hues of rubies are unrivaled by other stones and are reminiscent of the most beautiful flowers, leaves, and birds found in nature. Rubies are mentioned in the Bible eight times as an example of preciousness and beauty. Throughout Eastern and Western history, rubies have been treasured for their fiery beauty and durability. From ancient Hindu myths to Medieval European folklore, many have believed rubies to possess spiritual or magical powers; no wonder it took a pair of ruby slippers to get Dorothy out of Oz.
The most beloved rubies in the world actually grow in marble. These can be found in northern Vietnam and Myanmar (famous for “Burmese Rubies”) all the way across the Himalayas into Pakistan. Because marble has almost no trace iron, the reds of these rubies are very vibrant, and many of them floresce red in sunlight, giving them an alluring red glow. Other ruby sources include African mines like the one in Winza, Tanzania, but rubies found here do have larger amounts of iron, so they’re typically a more rusty red rather than a pure red, but there are lovely quality stones and not-as-lovely quality stones from every source, so it’s better to judge each stone on its own merit than to make too many generalizations.
The finest ruby grows in marble. (Image source- Wikimedia Commons).
Treatments in Rubies
Like many gems, rubies can be treated to enhance their appearance. Different types of treatments affect value differently. Permanence and durability are two factors that determine the quality of a gem’s treatment; if the enhancement to the gem is permanent and does not affect the durability of the stone, it’s much more acceptable in the fine jewelry world than temporary treatments or treatments that compromise the integrity of the stone.
Heat Treatment
Heat treatment is used to enhance a ruby’s color and has ancient roots. Thousands of years ago, ancient jewelers discovered that rolling rubies in hot coals enhanced their color. Now, high-tech furnaces are used to heat and cool rubies (and other stones) to precise temperatures at specific rates to achieve prettier colors. Heat can also be used to remove inclusions or even to create more silk-like inclusions to produce asterism (star rubies).
Heat treatment is permanent and does not affect a stone’s durability. Many gem collectors see heat as the only “acceptable” gem treatment because it’s really like fast-forwarding nature– if they had left the rubies in the ground, atmospheric pressure and geothermal changes would have eventually heated the rubies to achieve the same end. Heat treatment is detectable by a gemologist, and jewelers should always disclose if a ruby has been treated with heat or any other treatment.
Fracture Filling
Fracture filling is a process in which little fractures (that look like little cracks or fissures) that reach the surface of a ruby are filled with glass to lessen their appearance and make the ruby look more transparent. Fracture filling is permanent, but it does affect the durability of the stone. The glass (or other fill material) may not expand and contract in the exact same way as the natural corundum, which is a major problem; when exposed to the heat of a jeweler’s torch, if the fill material expands more than the corundum around it, the stone can seemingly spontaneously shatter. Yikes!
Fill-material may be silica-glass or leaded glass or something else. Some fill materials do better under heat than others, while others react more to common cleaning and jewelry-making chemical solutions, so it’s very important to know whether a gem has been fracture filled and disclose that information to any jeweler who may be doing repairs on the item. Fracture filled rubies are generally less expensive than their natural or heat-treated counterparts.
Diffusion
In recent decades, a process called lattice diffusion has been used to change the color of colorless (or beige-colored) corundum. Stones are basically bombarded with beryllium to change the chemical structure of their other layer. This is a superficial treatment that penetrates the outer layer of a stone. Most diffused rubies are easily detectable to professionals by their color zoning, with the color on the edges around a pale core. Diffusion doesn’t affect the durability of a stone, but, because the color imparted is so shallow, if the ruby ever needed to be recut or polished, it would drastically change the appearance of the stone; repolishing would be tantamount to wiping away the ruby’s lipstick. Diffused rubies are significantly less valuable than their natural and heated counterparts.
Lab-created
Rubies can be lab-grown just like many other gemstones. Lab-created gems are chemically idenitcal to their natural counterparts. Unlike imitation gemstones which only resemble the real thing on a superficial level, lab-created gems have the same chemical structure, physical properties, durability, and general makeup as gems found in the ground.
There are several ways to grow corundum in a lab, and the process has been around for decades. In fact, in the late 1800s, ruby became the first gem to be lab-grown. Auguste Verneuil, the developer of the technology, announced the development of his flame-fusion process for synthesizing this beautiful gem in 1902. Lab-grown rubies have traditionally been used since then as the jewels inside watch movements, and their excellent qualities as thermal conductors have made lab-created rubies important to many mechanical and scientific applications including the development of lasers. Since their initial development, new techniques have been developed for creating rubies in labs that create gorgeous gems. Lab-grown rubies are typically much more affordable and have fewer inclusions than many of their natural counterparts.
This lab-created ruby is housed in the National Museum of American History’s collection here in DC. It was used by Theodore Maiman of the Hughes Aircraft Company to create the first laser beam in 1960. (Image source: SI.edu)
Our Favorite Rubies:
The master jeweler at Secrete Fine Jewelry made this pretty floral-inspired necklace in 18k white gold, rubies, and diamonds.
This star ruby and diamond ring was hand-crafted at Secrete Fine Jewelry. Small needle-like inclusions create the asterism in the center stone.
The Carmen Lucia ruby is a beauty and extremely enormous 23.1ct unheated ruby housed at the Smithsonian Museum of Natural History here in Washington, DC. This ruby has mined in the Mogok region of Burma in the 1930s (now Myanmar) and is one of the largest fine, faceted rubies in the world. (Image source- SI.edu)
We made this gorgeous diamond and ruby ring at the original Secrete Fine Jewelry in Bethesda, MD years ago. We love the regal reds again the yellow gold.
Interested in adding rubies to your collection? Contact us today or visit our showroom in DuPont Circle in Washington, DC or the Wildwood Shopping Center in Bethesda, MD.
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