The perception and monetary value of gemstones have undergone dramatic transformations over millennia, driven by scarcity, discovery, cultural shifts, and the advent of synthetic production. In the Middle Ages and the subsequent Renaissance, the hierarchy of gemstone value was not static; it was a fluid construct influenced by the availability of materials, the routes of trade, and the specific desires of royalty and the merchant class. Unlike the modern era, where diamonds often dominate the market, the Middle Ages and the 16th century witnessed a period where ruby, emerald, and amethyst held the highest prestige and price tags, while diamonds occupied a surprisingly lower tier in the valuation hierarchy.
To understand the economic landscape of gemstones during this era, one must examine the specific valuation data recorded by historical figures like Benvenuto Cellini and the broader market forces that dictated price fluctuations. The valuation of a gemstone was not merely a function of its weight, but of its rarity, color saturation, and the perceived peril of its acquisition. The narrative of gemstone value is one of dramatic rises and falls, where the discovery of new mines could collapse a market, and the fabrication of synthetic stones could temporarily unsettle prices before the market stabilized through the ability of competent jewelers to distinguish natural from artificial material.
The Hierarchy of Value in the Middle Ages and Renaissance
During the Middle Ages, the valuation of gemstones was heavily influenced by the perceived dangers associated with their extraction and transport. Effective publicity played a significant role in elevating the value of gems. Trade narratives of the era were accustomed to exaggerating the perils of obtaining precious stones from Eastern gem fields. Given the rudimentary state of transportation at the time, the actual dangers were sufficient without the need to multiply the number of man-eating tigers, cannibals, or fantastical creatures like dragons and monstrous serpents that were said to waylay travelers. These stories served to inflate the value of stones, embedding a premium for the "peril factor" into the price structure.
In the 16th century, the hierarchy of gem valuation was starkly different from the modern "Big Four" ranking. Benvenuto Cellini, a renowned Italian Renaissance goldsmith, documented in his memoirs that the ruby was considered the most valuable of all gems, followed by the sapphire. The diamond, although far rarer during the Renaissance than it is today and largely reserved for nobles, was ranked only third in value. Cellini's records indicate that during this period, a fine diamond was worth only one-eighth of the price of a similarly high-quality ruby.
This ranking is corroborated by specific figures attributed to Cellini from 1558, which provide a snapshot of the market at that time. According to these records, the relative value of a one-carat stone was as follows:
- Ruby: $779.20
- Emerald: $389.60
- Diamond: $48.70
- Sapphire: $4.87
While these specific monetary figures from Cellini may reflect exceptionally fine stones or perhaps a degree of exaggeration on the part of the goldsmith, the relative ordering remains a critical historical data point. The ruby and emerald vied for the top spot throughout the 20th century, trading places several times, but in the Renaissance, the ruby stood supreme. The diamond, despite its modern dominance, had not yet captured the imagination of the market to the extent it has today.
The sapphire, while ranked fourth in Cellini's specific list, had a complex history. In the Middle Ages, the sapphire and ruby were known to the Etruscans and Greeks between 600 and 480 B.C. However, by the Middle Ages, the quartzes (which include amethyst) had declined in both respect and price as new deposits were exploited and long-distance trade routes from Asia and sub-Saharan Africa expanded. This expansion of trade meant that stones that were once exclusive became more accessible, leading to a depreciation in value for certain categories of stones.
The Rise and Fall of Amethyst and the Impact of Discovery
Amethyst, a variety of quartz, serves as a prime example of how geological discovery can instantly alter market dynamics. In ancient times, amethyst was highly valued for its deep purple hue, a color cherished by royalty. During the Renaissance, fine Indian amethyst traded for fully half the price of a precious sapphire, indicating its high status. However, the stone's fortune was inextricably linked to its scarcity.
The Age of Discovery, spanning from the 15th to the 18th century, proved detrimental to the reputation of many gemstones. Although amethyst remained relatively scarce until the early 19th century, massive discoveries in Brazil flooded the market in the 1830s and 1840s. This sudden influx of material caused the value of amethyst to collapse completely. The price never recovered from this shock. Even in the modern era, it is possible to purchase good quality amethyst for only a few dollars per carat. This historical trajectory illustrates a fundamental principle of gem valuation: the discovery of a new, abundant source can decimate the value of a stone that was previously a high-tier gem.
The term "carbuncle" in ancient Greece and Rome referred to any deep red gem. It is theorized that garnets, rubies, and red spinels were all interchangeably considered carbuncles during this period. The ancient understanding of gemstones was often broad and less precise than modern gemology. The decline of quartzes by the Middle Ages suggests that the market had shifted its focus to other materials as the supply of quartz-based gems increased due to expanded trade routes.
The Dynamics of the Diamond Market and Synthetic Competition
The history of the diamond market is a tale of fluctuating dominance. From about 26 A.D. to about 1500 A.D., a one-carat white diamond was the most expensive stone. However, from 1501 to about 1800, the ruby led the market. From 1801 until 1872, the diamond regained and held the lead. From that later date to the present day, the emerald has been the most expensive stone. This cyclical leadership highlights how the "king of gems" is not a permanent title but shifts based on supply, demand, and technological advancements.
A critical disruption in the gem market occurred in the late 19th and early 20th centuries with the advent of synthetic gemstones. In 1890, Fremy and Verneuil succeeded in producing synthetic rubies and sapphires. Synthetic rubies began to appear on the market in 1904–5, and sapphires followed in 1909–10. Initially, the entry of these man-made materials unsettled the prices of natural rubies and sapphires. However, the market stabilized around 1912 once it was established that the shortcomings of the man-made material could be readily detected by any competent jeweler. Following this recognition, the prices of natural rubies and sapphires resumed their upward course.
This episode underscores the resilience of natural gemstones. Even when faced with synthetic competition, the market corrected itself once the distinction between natural and artificial could be made reliably. The ability to detect synthetics prevented a permanent price collapse, ensuring that the value of high-quality natural stones remained robust.
Weight, Rarity, and the Square Law of Valuation
The valuation of gemstones has historically been tied to the weight of the stone. In 1592, Linschoten introduced a rule for the valuation of gems: the value of a stone of more than one carat is the product of the value of a one-carat stone by the square of the stone's weight. For example, if a one-carat stone is worth $X, a two-carat stone would theoretically be worth $X * 2^2 = 4X.
This "square law" has had varying degrees of accuracy over time. For the past sixty years relative to the source's context (early 20th century), this rule had become valueless in diamond valuation due to the extraordinary number of large stones reaching the market from South Africa. However, the rule remains approximately correct in ruby valuation. In the case of rubies, the resulting price calculated by this formula is too high for stones only slightly over a carat, and too low for stones of three carats or more.
The value of a gemstone is heavily concentrated in small weight and bulk. With the exception of radium and a few other very rare elements, the finer precious stones—the diamond, emerald, ruby, and sapphire—are the most valuable of all commodities. One could conceal a pound of such gems, potentially worth millions of dollars, around a person, a feat of wealth concentration unmatched by other commodities.
Nationalism, Color, and Regional Valuation Trends
Valuation is not solely determined by scarcity or color; nationalistic sentiment can cause a rare precious stone to be abnormally popular in its land of origin. A prime example is alexandrite in Czarist Russia. This stone was first found in the Urals on the day the Czarevitch Alexander Nicolajevitch (later Alexander II) came of age. This coincidence, combined with the stone's unique color-changing properties (green in natural light, red in artificial light), which matched the colors of the Imperial Guard, rendered it exceptionally popular in Russia.
Similarly, in America, local gems such as benitoite, kunzite, hiddenite, and tourmaline were more commonly used than in other regions, driven by national pride and local availability. The value of these stones was not intrinsic to their physical properties alone but was amplified by their connection to national identity.
The value of emeralds, in particular, is determined by the depth of color, brilliancy, and relative freedom from flaws. Flawless emeralds are practically non-existent. Stones of good quality over one carat increase in value by the square of the weight, a generalization that has held true since the 16th century.
Sapphires also faced significant market fluctuations. While the price of sapphire was much below that of the diamond in certain periods, Streeter reported in 1884 that some fine 2 to 3 carat stones were as valuable as diamonds of the same weight. The price of sapphires decreased between 1880 and 1905 due to the bringing into production of four important fields within a twelve-year period. These included the beginning of sapphire mining in Queensland (1881), the discovery of the Kashmir field (1882), the discovery of Phailin, Cambodia (1885), and the opening up of the Montana field (1893). This surge in supply dampened the price, though fine large sapphires remain rarer than rubies or emeralds. Consequently, the price increase per carat for sapphires is not as great as in those other gems; a ten-carat stone might be worth 40 to 60 times the value of a one-carat stone, a ratio that is less steep than the exponential growth seen in rubies.
Exceptional Stones and the Negotiated Market
The market for exceptionally fine gems operates under different rules than the standard retail market. Exceptionally fine gems are so rare that they have no fixed price, and each transaction becomes a matter of negotiation between buyer and seller. As with a fine painting or other work of art, set rules do not hold. This applies to red, green, or blue diamonds, white diamonds of unusual size and brilliancy, rubies of over four carats, emeralds of fine deep color and relatively free of flaws, and unusually fine sapphires.
The valuation of these unique stones is subjective and situational. For instance, exceptionally large rubies (3 to 9 carats or more), due to their great rarity, are the most expensive of stones. Such stones can command prices ranging from $3,000 to $7,000 a carat. The latest development in gemstone valuation has been the rise of new, ultra-rare gems, including colored diamonds, alexandrite, demantoid garnet, and Paraiba tourmaline. These "new" gems are exceedingly beautiful, extremely rare, and often exorbitantly expensive, challenging the traditional dominance of the "big four" (ruby, emerald, diamond, sapphire).
The historical record shows that while the diamond is currently holding onto the third slot in value, a top-quality, one-carat Burmese blue sapphire is nearly equal in value to a flawless, perfectly colorless, one-carat diamond. This shift reflects the dynamic nature of the market, where scarcity and desirability constantly redefine the hierarchy.
Conclusion
The history of gemstone valuation is a complex narrative of discovery, trade, and cultural influence. In the Middle Ages and Renaissance, the ruby and emerald stood at the apex of value, with the diamond lagging behind. The discovery of new mines, particularly in Brazil and South Africa, and the invention of synthetic gems, created periods of price instability that eventually stabilized as the market adapted to new supplies and detection methods. The value of a gem is not static; it is a product of its physical properties, its historical narrative, and the economic forces of supply and demand. From the square-law valuation of weight to the nationalistic boost for local stones, the market has consistently demonstrated that the worth of a gem is as much a reflection of human desire and history as it is of geology. As new ultra-rare gems enter the market, the hierarchy continues to evolve, proving that the crown of "most valuable" remains a contested and fluid title.