December 26th falls within a month uniquely distinguished in the realm of birthstones by its abundance of choice. While most months are assigned a single traditional gem, December boasts four official birthstones: turquoise, tanzanite, blue zircon, and blue topaz. Each of these stones shares a common thread—a spectrum of blue hues that mirrors the winter sky—yet they possess vastly different geological origins, historical narratives, and gemological properties. This article provides a comprehensive exploration of these four gemstones, delving into their historical significance, formation processes, scientific characteristics, and cultural symbolism, offering gemstone enthusiasts, jewelry buyers, and students of gemology a detailed guide to the gems of the twelfth month.
The evolution of birthstone lists is a historical process in itself, with December’s selection reflecting both tradition and modern discovery. The standardization of birthstones began in 1912 with the National Association of Jewelers, which combined historical customs with gemstones practical for the jewelry trade. This list has been updated over time, with blue zircon added in 1952 and tanzanite in 2002, demonstrating how new discoveries and market availability continue to shape the canon of birthstones. The inclusion of multiple options for December is often attributed to a desire to offer a variety of colors and styles, as well as to provide more affordable choices alongside rare and valuable specimens.
History and Lore
The historical narratives of these four gemstones span millennia, from ancient civilizations to modern mining operations, each carrying a legacy of cultural importance and symbolic meaning.
Turquoise stands as the most ancient of the December stones, with a history stretching back thousands of years. Its name is derived from the French pierre turquoise, meaning "Turkish stone," as the gem was introduced to Europe through Turkish gem markets, though its origins lie farther east. Historical sources indicate that turquoise was mined in Persia and along the Sinai Peninsula. From the earliest times, it was a favored gem for amulets due to its relative ease of being cut and inscribed. It was believed to possess protective powers against danger and to bring good fortune. Turquoise was especially prized by lovers and married couples, thought to protect relationships and preserve friendship when given as a gift. A persistent folk belief held that the stone could warn its wearer of impending illness or danger by becoming pale. In Tibetan culture, turquoise was considered a birthstone of fortune, health, and success, and was so valued that it was often used as currency. Similarly, ancient Incas and Mayas offered turquoise to their gods, and Native Americans of the Southwest associated the gemstone with youth and strength.
Tanzanite represents the modern end of the historical spectrum. Unlike the ancient stones, tanzanite is a 20th-century discovery, first identified in the 20th century in Tanzania. Its addition to the official birthstone list in 2002 marks it as the newest member of the December family. While its historical lore is brief compared to turquoise, it has quickly accumulated modern symbolism associated with transformation and new beginnings, reflecting its recent emergence into the gemological world.
Blue Zircon and Blue Topaz share a more complex historical narrative. The exact historical origin of blue topaz is described as unknown, having been found throughout history, suggesting a long but poorly documented presence. Blue zircon, while a natural gemstone, also has a history intertwined with imitation. For centuries, diamond substitutes were made from zircon, and its name is sometimes confused with cubic zirconia, a synthetic diamond simulant created in the 1970s. However, natural zircon is one of the oldest minerals on Earth. The addition of blue zircon to the official birthstone list in 1952 helped distinguish the natural gemstone in the public consciousness. Blue topaz is the official state gem of Texas, a designation that adds a layer of modern American heritage to its identity.
Geological Formation and Sources
The formation and sourcing of these gems are as diverse as their histories, ranging from single-point-source mines to widespread global deposits.
Turquoise is a hydrous phosphate of copper and aluminum, formed in arid regions where acidic, copper-rich groundwater seeps through pre-existing rocks and reacts with minerals containing aluminum and phosphorus. This process occurs in specific geological settings, leading to the formation of nodules or veins. Historically, major sources included Persia (modern-day Iran) and the Sinai Peninsula. While specific modern mining locations are not detailed in the provided materials, the historical trade routes from these regions to Europe via Constantinople established its global value.
Tanzanite is the rarest of the four December stones, with a unique geological origin. It is mined in only one specific region of Tanzania, which contributes to its rarity and high value. This single-source locality makes it geologically exclusive. Tanzanite is a variety of the mineral zoisite, and its formation is linked to specific metamorphic processes in that region of East Africa.
Blue Zircon is a mineral with the chemical formula ZrSiO₄. While the sources do not specify its mining locations, its durability and historical use suggest a relatively widespread occurrence, though high-quality gem material is less common. The provided materials do not detail specific countries of origin for blue zircon.
Blue Topaz is mined in several locations globally, including Sri Lanka, Brazil, Mexico, Nigeria, and the United States. Topaz is a silicate mineral of aluminum and fluorine, and natural blue topaz is quite rare. Much of the blue topaz on the market today is created by irradiating and heat-treating colorless topaz, a process that is not explicitly detailed in the provided chunks but is a standard industry practice. The wide geographic distribution of its sources makes it more accessible than tanzanite or high-quality turquoise.
Gemological Properties
The gemological properties of these four stones vary significantly, affecting their durability, appearance, and care requirements. The following table summarizes key properties as detailed in the provided sources.
| Gemstone | Chemical Composition | Mohs Hardness | Key Characteristics | Durability for Jewelry |
|---|---|---|---|---|
| Turquoise | Hydrous copper aluminum phosphate | Not specified | Can vary in color from soft sky blue to greenish hues. Often has a porous structure. | Softer and more delicate; requires careful handling. |
| Tanzanite | Calcium aluminum hydroxyl sorosilicate (variety of zoisite) | Not specified | Known for its striking pleochroism (showing different colors from different angles) and rich violet-blue color. | Also considered fragile. |
| Blue Zircon | Zirconium silicate (ZrSiO₄) | 6.5–7.5 | Can be cleaned with a soft cloth and mild soap. Less sensitive to heat and chemicals than other December stones. | More durable than turquoise and tanzanite. |
| Blue Topaz | Aluminum silicate with fluorine and hydroxyl | 8 | The hardest of the four December birthstones. Can be cleaned with a soft cloth, mild soap, or ultrasonic cleaning. Less sensitive to heat and chemicals. | Excellent for everyday wear due to its hardness. |
Turquoise is relatively soft, which aligns with its historical use for amulets and inscribed objects, as it is easier to work with. However, this softness makes it susceptible to scratching and damage, requiring protective settings for jewelry.
Tanzanite is noted for its fragility, similar to turquoise. Its most famous gemological property is pleochroism, the ability to display different colors—typically blue, violet, and burgundy—when viewed from different crystallographic directions. This characteristic is a key feature of its beauty and value.
Blue Zircon has a Mohs hardness of 6.5 to 7.5, placing it in the range of moderate durability. It is less sensitive to heat and chemicals than some of the other December stones, making it a relatively resilient choice, though it still requires care to avoid damage from sharp blows.
Blue Topaz is the hardest of the group, with a Mohs hardness of 8. This high hardness makes it very resistant to scratching and suitable for daily wear in rings and bracelets. It is also noted as being less sensitive to heat and chemicals, and it can withstand ultrasonic cleaning, a cleaning method not recommended for softer stones like turquoise and tanzanite. Its clarity is often high, providing a brilliant sparkle.
Symbolism and Metaphysical Beliefs
The symbolism attached to each gemstone is deeply rooted in its history and cultural associations.
Turquoise is overwhelmingly associated with protection, good fortune, and friendship. Its historical role as an amulet for travelers, a guard against danger, and a preserver of relationships cements its symbolic meaning. The belief that it could change color to warn of health issues adds a layer of personal connection and mystique. For Native American cultures, it represents youth and strength, while Tibetans link it to health, success, and fortune.
Tanzanite, as a modern gem, has come to symbolize transformation and new beginnings. Its recent discovery and unique color are often interpreted as representing a fresh start or a significant change in one's life, aligning with its status as a 21st-century birthstone.
Blue Zircon is associated with clarity, wisdom, and balance. These metaphysical beliefs likely stem from the gem's often brilliant clarity and its position as a durable, balanced stone in terms of hardness and beauty.
Blue Topaz, particularly in its imperial form (a warm orange-pink), has other associations, but for the blue variety, it is linked to calm, communication, and clarity of thought. Its durability and clear blue color evoke a sense of stability and serenity.
Care and Cleaning
Proper maintenance is essential to preserve the beauty of these gemstones, and care instructions are directly tied to their physical properties.
Turquoise is the most delicate of the four. It should be protected from chemicals, extreme temperatures, and humidity, which can damage its porous structure and cause discoloration. Cleaning should be done with a soft, dry cloth; water and soaps should be avoided as they can be absorbed.
Tanzanite also requires gentle handling due to its fragility. It is susceptible to scratches and should be stored separately from harder gems. Cleaning with a soft cloth and mild soap is recommended, avoiding ultrasonic cleaners and harsh chemicals.
Blue Zircon is more robust. It can be cleaned with a soft cloth and mild soap. It is noted as being less sensitive to heat and chemicals than the other December stones, making it somewhat easier to maintain.
Blue Topaz is the most resilient. As the hardest of the group, it can be cleaned with a soft cloth, mild soap, and even with an ultrasonic cleaner. Its resistance to heat and chemicals makes it a practical choice for jewelry that is worn daily and may encounter various environments.
Conclusion
The birthstones for December—turquoise, tanzanite, blue zircon, and blue topaz—offer a remarkable diversity within a unified blue color palette. Turquoise provides a tangible link to ancient civilizations and enduring symbols of protection and friendship. Tanzanite introduces a note of modern rarity and transformative symbolism. Blue zircon and blue topaz offer durable, brilliant options for everyday wear, with blue topaz standing out as the hardest and most practical for active lifestyles. Together, they represent a spectrum of geological wonders, from the ancient and widespread to the recently discovered and geographically confined. For anyone born in December, this quartet of gems presents a unique opportunity to choose a stone that not only matches a personal aesthetic but also carries a deep historical and symbolic significance, making it far more than a simple piece of jewelry.