December is unique in the birthstone calendar, traditionally associated with multiple gemstones that share a cool, wintry palette of blues. This abundance offers a variety of choices for those born in the final month of the year, each with distinct histories, properties, and symbolic meanings. The modern list of December birthstones includes turquoise, zircon, tanzanite, and blue topaz. While turquoise is the most historically recognized, the list has evolved over time, reflecting both ancient traditions and modern gemological discoveries. This article provides a detailed exploration of these four gemstones, drawing from their historical origins, geological formation, gemological properties, cultural symbolism, and practical care guidelines.
History and Lore
The tradition of assigning specific gemstones to calendar months has ancient roots, but the official standardization of birthstones is a more recent development. In 1912, the American National Association of Jewelers (now known as the Jewelers of America) adopted and standardized a modern list of birthstones. This list designated turquoise and zircon as the two official birthstones for December (Source 1). The list has been updated since then. In 1952, the Jewelry Industry Council of America added zircon to December’s list (Source 4). More recently, in 2002, tanzanite was added as an official December birthstone (Source 4). Blue topaz is also widely recognized as a December birthstone, though its addition was more gradual and is sometimes associated with commercial offerings and the need for more affordable options (Source 4).
Turquoise: The Ancient Talisman
Turquoise is arguably the oldest and most historically significant of the December birthstones. Its name is derived from the French pierre turquoise, meaning "Turkish stone," as it was brought to Europe through gem markets in Constantinople, Turkey (Source 3). However, its origins lie in Persia and along the Sinai Peninsula. The oldest known turquoise mines date back to 3200 BCE in ancient Egypt, where the stone was prized for its brilliant robin’s egg blue color (Source 1).
Throughout history, turquoise has been a favored gem for amulets and protective charms. Its relative softness made it easy to cut into various shapes and inscribe upon. Ancient cultures believed it possessed the power to protect against danger and bring good fortune. In Persia and among Native American tribes of the Southwest, it was associated with youth, strength, and health (Source 3). Tibetan culture held turquoise in high regard, considering it a birthstone of fortune, health, and success, and even using it as a form of currency (Source 3). The stone was also believed to warn its wearer of approaching illness or danger by changing color, typically becoming pale (Source 3).
Turquoise has adorned some of history’s most famous artifacts. It decorated Tutankhamun’s burial mask alongside gold, lapis, and obsidian. Queen Zarina’s ancient Persian crown was set with over 150 turquoises. In more modern times, it has been featured in pieces like Paul Morelli’s 18K hammered gold cuff with American turquoise cabochons (Source 1).
Zircon: The Gem of Fire and Clarity
Zircon has ancient origins, mentioned in Hebrew, Arabic, and Greek texts as early as the 5th century BCE (Source 1). The word “zircon” is believed to come from the Persian word zargun, meaning "gold-colored," which reflects the gem’s historical association with a range of warm hues. However, zircon is most famous today for its brilliant fire and colorless varieties, which have been historically imitated for other gems like diamonds (Source 1). The more colorless varieties have been the most highly prized throughout history.
Zircon’s history in jewelry is marked by its use in royal and iconic pieces. It was featured in the tiaras of Marie Antoinette and in Van Cleef & Arpels’ 1939 Zip Necklace. Harry Winston’s Premier Chinese New Year Dragon brooch is another famous example, adorned with thousands of zircons (Source 1). Beyond its aesthetic appeal, zircon is associated with healing, hope, wisdom, and clarity (Sources 1, 5).
Tanzanite: The Modern Marvel
Tanzanite is the newest addition to the official December birthstone list, added in 2002 (Source 4). It is a relatively modern discovery, first found in the Merelani Hills of Tanzania in the mid-20th century. Its stunning blue-violet color, a result of vanadium impurities, quickly captivated the gemstone world. Its symbolism is tied to modern themes of transformation, growth, and fresh chapters, reflecting its blue-violet tone as a guide into new experiences with clarity and curiosity (Source 5).
Blue Topaz: The Durable Blue
Blue topaz’s historical origin is less clearly documented, with the stone being found throughout history (Source 4). Its inclusion as a December birthstone is largely attributed to its availability, affordability, and durability. It is mined in several countries, including Sri Lanka, Brazil, Mexico, Nigeria, and the United States, and is the official state gem of Texas (Source 4). While it lacks the ancient lore of turquoise or zircon, blue topaz is valued for its crisp winter blue color and its exceptional hardness, making it an excellent choice for everyday jewelry (Source 4).
Geological Formation and Sources
Each of the December birthstones forms under distinct geological conditions and is sourced from specific regions around the world.
- Turquoise: Turquoise is a secondary mineral that forms in arid regions where acidic, copper-rich water percolates through rocks containing aluminum and phosphorus. The interaction of these elements over millions of years creates the hydrated copper aluminum phosphate that is turquoise. Historically, significant mines were located in ancient Egypt and Persia. Today, major sources include the United States (particularly Arizona and New Mexico), Iran, China, and Egypt (Sources 1, 3).
- Zircon: Zircon is a mineral belonging to the group of nesosilicates. It is one of the hardest minerals on Earth and is commonly found in igneous and metamorphic rocks. It can form as a primary crystal in magma or as a detrital grain in sedimentary deposits. Major sources for gem-quality zircon include Australia, Cambodia, Myanmar, Sri Lanka, and Tanzania (Source 1).
- Tanzanite: Tanzanite is a variety of the mineral zoisite, colored by vanadium. It is found exclusively in a small, mining area in the Merelani Hills of northern Tanzania, near Mount Kilimanjaro. This extremely limited geographic source makes tanzanite one of the rarest gemstones in the world (Source 4).
- Blue Topaz: Topaz is a silicate mineral of aluminum and fluorine. Natural blue topaz is quite rare; most of the blue topaz on the market is colorless topaz that has been treated with irradiation and heat to achieve its blue hue. Commercial sources include Brazil, Sri Lanka, Nigeria, Mexico, and the United States (Source 4).
Gemological Properties
Understanding the physical and optical properties of these gemstones is crucial for gemologists, jewelers, and consumers. The following table summarizes key gemological data for the four December birthstones, based on information from the provided sources.
| Gemstone | Typical Color Range | Hardness (Mohs Scale) | Crystal System | Notable Properties |
|---|---|---|---|---|
| Turquoise | Sky blue to blue-green | 5 - 6 | Triclinic | Often contains a matrix (webbing). Prized for its uniform color. |
| Zircon | Colorless, yellow, red, brown, blue | 7.5 | Tetragonal | High refractive index and strong dispersion ("fire"). |
| Tanzanite | Blue to violet-blue | 6.5 - 7 | Orthorhombic | Pleochroic, showing different colors (blue, violet, burgundy) from different angles. |
| Blue Topaz | Light to deep blue | 8 | Orthorhombic | Often treated to achieve color. Very durable for jewelry. |
Turquoise is relatively soft (5-6 on the Mohs scale) and has a triclinic crystal structure. Its color ranges from sky blue to blue-green, often influenced by the presence of a host rock matrix, which can create a desirable "spiderweb" pattern. Its softness makes it susceptible to scratching and chemical damage, requiring careful handling (Source 1).
Zircon is significantly harder, with a Mohs hardness of 7.5, and has a tetragonal crystal system. It exhibits a high refractive index and strong dispersion, giving it a brilliant sparkle that can rival diamonds. Its color range is extensive, including colorless, yellow, red, brown, and blue varieties (Source 1). The blue variety is often heat-treated to produce a more stable and desirable color.
Tanzanite has a hardness of 6.5 to 7 on the Mohs scale and an orthorhombic crystal system. Its most defining characteristic is its strong pleochroism, meaning it displays different colors—typically blue, violet, and burgundy—from different viewing angles. This property requires careful cutting by gem cutters to present the most desirable blue-violet hue from the top (Source 4).
Blue Topaz is the hardest of the December birthstones, with a Mohs hardness of 8, and shares an orthorhombic crystal system with tanzanite. Its durability makes it ideal for rings and other jewelry worn daily. As noted, most blue topaz on the market is colorless topaz that has been treated with irradiation and heat. The resulting color can range from a pale sky blue to a deep "London Blue" hue (Source 4).
Symbolism and Metaphysical Beliefs
The symbolism attached to the December birthstones is as diverse as the stones themselves, drawing from centuries of cultural beliefs and modern interpretations.
- Turquoise is universally regarded as a stone of protection, healing, and good fortune. Ancient cultures believed it could warn of danger or illness by changing color. It is seen as a steadying force, promoting wisdom, prosperity, and calm. In relationships, it was thought to preserve friendship and protect love, making it a cherished gift between partners (Sources 1, 3, 5).
- Zircon is associated with clarity, focus, and mental acuity. Its brilliant fire is said to sharpen the mind and boost spiritual awareness. Historically, it has been linked to healing and hope, providing comfort and promoting a sense of balance and stability (Sources 1, 5).
- Tanzanite, as a modern discovery, carries contemporary symbolism. It is linked to transformation, spiritual growth, and stepping into new chapters of life. Its unique blue-violet color is believed to facilitate clarity of thought and encourage curiosity and open-mindedness (Source 5).
- Blue Topaz is often associated with calm, clarity, and communication. Its cool blue color is reminiscent of serene winter skies, and it is believed to promote honest communication and emotional balance. Its durability symbolizes steadfastness and resilience (Source 4).
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones, and it varies significantly based on their hardness and chemical stability.
- Turquoise: Due to its relative softness (5-6) and porous nature, turquoise requires gentle care. It should be protected from chemicals, including perfumes, lotions, and household cleaners, which can damage its surface and cause discoloration. Clean it only with a soft, damp cloth and mild soap. Avoid ultrasonic cleaners and steam cleaners. It is best to store turquoise jewelry separately to prevent scratching (Source 1).
- Zircon: With a hardness of 7.5, zircon is relatively durable but can be brittle due to its crystal structure. It is susceptible to chipping if struck hard. Clean zircon with warm water, mild detergent, and a soft brush. Avoid sudden temperature changes, as some zircon can be sensitive to heat. Ultrasonic cleaners are generally safe, but steam cleaning should be avoided (Source 1).
- Tanzanite: Tanzanite’s hardness of 6.5 to 7 makes it suitable for most jewelry, but it requires careful handling due to its cleavage planes. It is sensitive to blows and can chip or fracture if impacted. Clean with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam, as the heat and vibrations can damage the stone. It is also advisable to remove tanzanite jewelry during physical activities (Source 2).
- Blue Topaz: As the hardest December birthstone (Mohs 8), blue topaz is very durable and suitable for everyday wear. It can be cleaned with warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe, but steam cleaning should be avoided for stones that have been fracture-filled (though most commercial blue topaz is not). Its color is stable under normal conditions, but prolonged exposure to intense heat could potentially alter it (Source 4).
Conclusion
The December birthstones—turquoise, zircon, tanzanite, and blue topaz—offer a remarkable diversity of choice, united by their captivating blue hues yet distinguished by their unique histories, properties, and meanings. Turquoise carries the weight of ancient civilizations and protective lore. Zircon offers brilliant fire and a connection to mental clarity. Tanzanite represents modern discovery and spiritual transformation. Blue topaz provides exceptional durability and a crisp, wintry color. Together, they form a rich tapestry of gemological heritage, making them not only beautiful adornments but also meaningful symbols for those born in the final month of the year. Whether chosen for their historical significance, symbolic power, or sheer beauty, these gemstones continue to hold a special place in the world of fine jewelry and personal adornment.