The practice of associating specific gemstones with birth months is a tradition that resonates deeply within modern culture, serving as a cornerstone of the jewelry industry and a personal touchstone for millions. Yet, the journey from ancient religious artifact to a standardized commercial list is a complex narrative, not dictated by a single authority but shaped by millennia of theological interpretation, cultural evolution, and modern commercial interests. The assignment of birthstones is not the work of a solitary decree but rather a cumulative process influenced by ancient historians, religious scholars, trade guilds, and ultimately, international trade associations. Understanding who determined birthstones requires a journey through biblical history, medieval astrology, and the pivotal standardization efforts of the 20th century.
Ancient Origins: The Biblical and Classical Foundations
The genesis of the birthstone tradition is most commonly traced to a singular, powerful religious artifact described in the Hebrew Bible: the Breastplate of Aaron. According to the Book of Exodus, the high priest of the Israelites wore a ceremonial breastplate, or hoshen, set with twelve distinct gemstones. These stones were arranged in four rows of three and were not merely decorative; they symbolized the twelve tribes of Israel. The original stones, as listed in Exodus 28:15-30, included Sardius, Topaz, Carbuncle, Emerald, Sapphire, Diamond, Ligure, Agate, Amethyst, Beryl, Onyx, and Jasper. This garment established an early, powerful link between specific stones and a collective identity, though it did not associate them with individual births or calendar months.
The critical pivot from tribal representation to personal, calendrical significance occurred centuries later through the interpretative work of classical scholars. In the 1st century AD, the Roman-Jewish historian Flavius Josephus wrote extensively on the subject. In his work Antiquities of the Jews, Josephus proposed a connection between the twelve stones of Aaron's breastplate and the twelve signs of the zodiac. He theorized that each gemstone held special powers corresponding to its associated astrological sign. This interpretation marked a fundamental shift, moving the stones from a collective symbol to a tool for individual, perhaps even therapeutic or talismanic, benefit.
This idea was further developed and cemented by St. Jerome in the 5th century AD. Building upon Josephus’s work, St. Jerome is credited with establishing the formal link between the twelve stones and the twelve months of the year. His writings suggested that an individual could derive specific benefits by wearing the gemstone corresponding to their birth month. This theological and astrological framework laid by Josephus and St. Jerome became the bedrock upon which the entire Western birthstone tradition was built. Their interpretations, though based on the same biblical source, effectively created the first "who" in the decision-making process—a council of early scholars who translated religious symbolism into personal adornment.
The Middle Ages: Evolution and Cultural Adoption
Following the intellectual contributions of Josephus and St. Jerome, the concept of birthstones evolved significantly during the Middle Ages. The practice was no longer confined to scholarly texts but began to permeate cultural and religious life. One notable adaptation was the integration of gemstones with the twelve apostles of Christianity. In some European traditions, each apostle was linked to a specific stone, such as Jasper for Peter and Ruby or Carbuncle for Andrew. This practice continued to reinforce the idea of a direct correlation between a person and a specific gem, further embedding the concept into the cultural consciousness.
During this period, a significant divergence emerged in how the stones were to be used. While the concept of birthstones as we understand it today—involving a single stone for a specific birth month—was still developing, a different practice gained traction in the Middle Ages. This was the acquisition of all twelve "natal stones" and wearing the one appropriate for the current month. This approach allowed an individual to harness the therapeutic or talismanic powers of each stone throughout the year, a practice that reflected the deep-seated belief in the stones' celestial influence.
The practice of wearing a single stone corresponding to one's birth month, the custom most familiar today, is believed to have solidified much later. Sources suggest this tradition began in 16th-century Germany or Poland. By the late 1500s, women in northern Europe had started wearing only the stone that represented their birth month or zodiacal sign for the entire year, moving away from the practice of cycling through all twelve. This regional adoption in Central Europe was a crucial step in refining the tradition into its modern form, demonstrating that the "decision" was a gradual, grassroots process influenced by local customs and beliefs.
The Modern Era: Kunz and the Push for Standardization
As the tradition moved into the modern era, it lacked a unified, authoritative list. Different cultures and regions often had varying assignments for the months, leading to confusion for both consumers and the burgeoning jewelry trade. The late 19th century saw a renewed interest in these traditions, largely driven by the efforts of one of America's foremost gemologists, George Frederick Kunz.
Kunz, a self-taught gem expert and writer considered America’s first gemologist, played a pivotal role in reviving and popularizing the concept of birthstones. In 1891, his employer, the prestigious New York jewelry firm Tiffany & Co., published his influential 36-page booklet, Natal Stones: Sentiments and Superstitions Connected with Precious Stones. Kunz’s work was instrumental in consolidating what had been an informal and often contradictory tradition into a more coherent narrative. He documented historical beliefs, cultural practices, and the supposed powers of various stones, effectively bridging the gap between ancient lore and modern commercial appeal. His efforts sparked a significant revival of interest in birthstones, creating a clear demand for a standardized list that the jewelry industry could adopt.
The need for standardization was met in the early 20th century by a formal trade body. In 1912, the National Association of Jewelers (which later became the Jewelers of America) convened to create an official, standardized list of birthstones for the United States. This was the first time a single, authoritative list was established, resolving the inconsistencies that had persisted for centuries. The decision was made not by historians or theologians, but by a commercial organization aiming to create a stable and predictable market. This 1912 list formed the basis of the modern birthstone assignments we recognize today.
The Influence of Commerce and Ongoing Evolution
The standardization by the National Association of Jewelers in 1912 marked the culmination of a long historical process, but it did not freeze the tradition. The list has been subject to revisions, reflecting both changing tastes and commercial interests. Subsequent modifications were made in 1952, 2002, and 2016. For example, the 1952 revision included the addition of Alexandrite and Zircon, changes that were influenced by market availability and the strategic interests of the gem and jewelry industry.
These revisions underscore a critical aspect of the birthstone story: the interplay between ancient tradition and modern commerce. While the symbolism of birthstones continues to hold profound meaning for many, the official lists are maintained by trade organizations that must consider the economic realities of the gemstone market. The inclusion of new stones often reflects a desire to offer more options to consumers or to promote the use of certain gems. Therefore, the "decision" regarding birthstones is an ongoing one, shaped as much by economic factors and industry interests as it is by historical and cultural significance.
Conclusion
The question of who determined birthstones does not have a simple answer. The tradition is a rich tapestry woven from multiple threads of history. Its origins lie in the biblical account of Aaron's breastplate, a sacred garment symbolizing a collective identity. The pivotal shift towards personal, monthly associations was engineered by ancient scholars like Flavius Josephus and St. Jerome, who interpreted religious texts through the lens of astrology. The practice was then filtered through medieval culture and regional customs before being popularized and consolidated in the modern era by influential figures like George Frederick Kunz. Ultimately, the tradition was formalized and standardized by the National Association of Jewelers in 1912, an act that cemented the modern list while ensuring its continued evolution through subsequent commercial revisions. Thus, birthstones are the product of a long, collaborative, and ever-changing dialogue between faith, culture, and commerce.