The Balas Rubies and Ruby Spinels Confusion

For centuries, balas rubies were prized by royalty. Learn what happened after gemologists identified these gems as red spinels instead.

History

Anyone studying spinels will soon read that, historically, red spinels have been misidentified as rubies. In fact, the most famous red spinels — the Black Prince's Ruby and the Timur Ruby — were thought to be rubies and still bear those popular but erroneous names. So, why were red spinels misidentified as rubies? The answer to that question involves some gemology and the history of the spinels once famously known as "balas rubies."

Rubies are Red, Sapphires are Blue, Spinels are Both: an old misunderstanding

Spinels are beautiful, durable gemstones that occur in various colors, including deep reds that rival rubies and cobalt blues that rival sapphires. Unfortunately, that rivalry with corundum — the mineral species that includes rubies and sapphires — hasn't always favored spinel. For centuries, red spinel was considered a type of ruby: a "balas ruby."

How Does Modern Gemology Distinguish Ruby and Spinel?

Gemologists now distinguish spinel and corundum as distinct gem species. Chemical formulas and crystal structure define gem species. Corundum, for example, has a chemical formula of Al2O3 and a hexagonal crystal structure. Ruby is the red variety of corundum, and the presence of chromium impurities creates its red color. All other varieties of corundum are called sapphires, with various impurities creating other colors like blue, purple, and pink. Colorless corundum, without impurities, is considered white sapphire.

Spinel has a chemical formula of MgAl2O4 and an isometric crystal structure. Various impurities in spinels create different colored varieties. As it turns out, chromium impurities also create red color in spinel. Colorless spinel, without impurities, occurs extremely rarely in nature.

Although red spinels and rubies may have a superficial resemblance (and may even form in the same rock formations alongside each other), their chemical and structural differences make them distinct types of gems. Gemologists would need to conduct a series of tests on a red gemstone's optical and physical properties to determine whether it's a ruby, spinel, garnet, or something else.

How Did People Distinguish Gemstones Before Modern Gemology?

Many of today's most well-known types of gemstones were named, cut, and treasured millennia ago. Before the advent of modern science, people still strove to identify and classify the natural world around them. However, their approaches and classification systems differed from that of modern science. In general, they grouped gems according to color.

Take the case of the red gemstones now known as rubies, red spinels, and red garnets. As Vincent Pardieu, Richard Hughes, and Edward Boehm note, "for most of human history," these were "simply sold as 'red stones,'" but Red stones were commonly grouped together in categories like carbuncles and rubies. (The name "ruby" even comes from the Latin word ruber for red). However, some of the observable differences of red stones didn't escape notice. This brings us to the topic of balas rubies.

The Demand for Rubies in the Middle Ages

Rubies — understood historically as "red stones" — were highly prized. C. Griffith Mann writes: During the Middle Ages, deep-red rubies were imported into Europe from India, Sri Lanka, and Burma. From Afghanistan, merchants brought paler, pinkish stones known as balas, or spinel rubies, which were not as prized because of their less brilliant coloration. Rubies were deemed chief among stones, and those as bright and lustrous as pomegranate flesh were especially celebrated.

Evidently, not all rubies — even in the historical sense — were treated equally.

The Identification of Balas Rubies

Modern gemology has identified many of these so-called "balas rubies" as spinels. Balas rubies were named after Balascia or Badakhshan, the region where they were mined. (Badakhshan now lies within modern-day Afghanistan, China, and Tajikistan).

Arab scholars were among the first to study these stones. The gemologist Richard Wise notes that Al-Biruni was the first to mention balas rubies in the 10th century CE. Ahmad al-Tifashi (1184-1253 CE) even distinguished spinels from rubies because rubies could scratch spinels. (354) In fact, ruby does have a greater hardness (9) than spinel (7.5-8). Long before the development of the Mohs scale of hardness in 1812, people observed, tested, and compared the resistance of different minerals to scratching.

The Rise of Balas Rubies

From the historical record, it is clear that the Badakhshan mines were of great importance during the period from 1000-1900 AD. While it is impossible to speculate about ruby, it is safe to say that, based on the numerous historical accounts, the Badakhshan mines were the source of many of the finest early red spinels in gem collections around the world, such as those in the crown jewels of Iran, the collection in Istanbul's Topkapi, Russia's Kremlin and Diamond Fund, and England's Tower of London.

A Ruby by Any Other Name?

Balas rubies were valued by the royalty of Europe, the Middle East, and Asia. However, those values varied considerably throughout the ages and in different cultures. Medieval and Early Modern gem enthusiasts distinguished different kinds of "rubies" and their desirability. Wise records some fascinating historical examples of these valuations of balas rubies or spinels:

• Ahmad al-Tifashi (1184-1253 CE) wrote that spinels had half the value of rubies. (354)
• In 1572, the Spanish goldsmith Juan de Arfe de Villafañe compared the values of diamond, ruby, oriental emerald, Colombian emerald, and red spinel. Between one and ten carats, red spinels or "balas rubies" consistently had half the value of diamonds of the same size. (350, 353)
• Of the crown jewels of France, balas rubies were the "glory of royal treasuries" until the end of the 16th century. (350-351)
• Aurangzeb, the Mughal Emperor of India (1618-1707 CE), received as tribute a large red stone purported to be a ruby. Suspicious of the gift, he sent the stone to his imprisoned father, the former emperor Shah Jahan, and asked him if it was "a true ruby or a balas ruby." Shah Jahan identified the stone as a balas ruby. Although the stone was originally purchased for 95,000 rupees, Shah Jahan valued it at "no more than 500 rupees." (353-354)

The supposed historical "inability to discriminate between ruby and spinel," writes Wise, "is a bit overblown." (353) Clearly, Arab scholars and others distinguished rubies and red spinels. However, for Medieval and Early Modern connoisseurs, rubies and red spinels were all still red stones. The differences between rubies and spinels were noted and evaluated, but color categories remained fundamental. In other words, the differences mattered, but they didn't lead to a categorical separation of rubies from red spinels. They remained "red stones."

Balas Rubies and the Importance of Size

The size of balas rubies failed to impress the Mughal emperors. However, as Wise notes, European rulers prized these large gems. Because they were large, spinels were "the red gems of choice amongst royalty" and were imported into Europe in significant quantities beginning in the 10th century CE. (355)

Spinels occur more commonly than rubies. While deep-red rubies were prized, balas rubies with lighter hues were simply more plentiful. Since gem-quality spinel crystals can grow to sizes larger than ruby crystals, they can also yield larger cut gemstones. For some European royalty, the size of the "ruby" was more important than its color, particularly for ostentatious display on symbols of power.

Historically, finished spinels could weigh hundreds of carats, perfect for royals trying to make a statement. Indeed, the famous 170-ct Black Prince's Ruby still graces the Imperial State Crown, which British kings and queens wear as part of their Coronation Regalia. It's so large and prominent on the Crown that the many millions of spectators watching the coronation of King Charles III on TV and online will make it — a spinel — one of the most noticed gemstones in the world.

When Did Balas Rubies Become Spinels?

The gem name "spinel" comes from the Latin spina for "thorn" or "spine," possibly referring to its crystal shape. Officially, spinels were named in 1779 by Jean Demeste. However, the name "spinel," or a close variation, had been used for red gemstones centuries prior. The gemologist Jeffery Bergman has noted references to gemstones as "spinelles" in the writings of the English scholars Richard Eden, in his 1555 translation of a Latin work by Peter Martyr d'Angliera, and Richard Haklyut in 1589. As Eden translates d'Angliera: There is also founde an other kynde of Rubies which wee caule Spinelle and the Indians, Caropus. They growe in the selfe same countrey of Pegu where as are the fine Rubies. And are found in the mountaynes in the vpper crust or floure of the earth. These are not so fine nor of so good colour is are the trewe Rubies: But haue sumwhat the colour of a granate which we commonly caule a garnet. (1555)

The 18th century saw the definitive scientific separation of rubies from spinels. In 1783, the French mineralogist Jean-Baptiste L. Romé de l'Isle analyzed multiple red stones thought to be rubies from Sri Lanka, Burma, and Southeast Asia. He soon realized that he had two distinct gem species rather than varieties of a single species.

De l'Isle's findings led to the examination of many famous "balas rubies." The results surprised some powerful owners. As it turned out, some of the most famous and valuable rubies, like the Black Prince's Ruby, were actually spinels.

After the Categorical Separation of Rubies from Red Spinels

Despite the definitive scientific separation, the comparisons between ruby and red spinel continue to this day, and they typically don't favor spinels. When red spinels were balas rubies, their size and availability made them popular with royalty, even if they couldn't match the deep-red color of "true rubies." However, after science forever separated spinel and ruby as different species, ruby kept its fame and value, while red spinel gained a reputation as a gem that resembles another more famous and valuable gem. Even today, you'll commonly find synthetic spinels of all colors used as beautiful, durable, and inexpensive simulants for other more costly gemstones, especially in birthstone jewelry and class rings.

Consider the recent visibility of the Black Prince's Ruby. Unfortunately, most coronation viewers will likely believe it's a ruby because of the gem's name. Although spinel is gaining in popularity — especially "Jedi" neon-pink and cobalt blue varieties — it's still a relatively little-known gem. Compared to ruby's fame and luxurious mystique, red spinel's reputation can't compete. So, even more unfortunately, those viewers who do learn that the Black Prince's Ruby is a spinel may rapidly lose interest in it.

What are "Ruby Spinels"?

In the contemporary gem trade, the association of red spinel with ruby persists, particularly regarding color. Like emerald, ruby has entered popular speech as a color descriptor. "Emerald green" and "ruby red" are evocative descriptions of color. However, at times, "emerald" and "ruby" are used as color names by themselves. This is usually innocuous, as in "emerald eyes" and "ruby lips." However, when used to describe colors in gemstones, these terms can lead to misunderstandings.

You might find gems described or sold as "ruby spinels" or "spinel rubies." This typically means the spinel has a deep red "ruby-like" color. These spinels have a red hue with a dark tone. (Red-hued spinels with a lighter tone will appear pinker).

While "ruby-like" might be an acceptable way to describe a deep-red color in non-gemstones, terms like "ruby spinel" and "spinel ruby" are misleading. Rubies have greater name recognition than spinels and typically command higher prices. To describe a stone as a "ruby spinel" or "spinel ruby" implies it's a type of ruby and thus merits a higher price. These terms lean too heavily on ruby's reputation to provide an unbiased description of a spinel's color.

Unfortunately, this type of practice also occurs in the gem trade with other stones. For example, you'll sometimes find morganite, pink beryl, marketed as "pink emerald." Emerald is the green variety of beryl. In this case, emerald and morganite are the same species, but emerald has greater name recognition and higher prices than morganites.