For those born on the final day of the year, December 31, the designation of a birthstone is not singular but tripartite. This unique date is associated with three distinct and remarkable gemstones: Tanzanite, Turquoise, and Zircon. Each stone presents a different chapter in the story of geological formation, human history, and cultural symbolism. From the ancient, earthy appeal of Turquoise to the recent, vibrant discovery of Tanzanite and the brilliant fire of Zircon, this trio offers a diverse palette of colors, properties, and meanings. For the gemstone enthusiast, jewelry buyer, or student of gemology, understanding the individual characteristics of these three stones provides a deeper appreciation for their collective significance as the birthstones of the year's culmination.
The historical journey of these stones is as varied as their appearance. Turquoise stands as one of the oldest known gemstones in human adornment, with a legacy stretching back millennia. In contrast, Tanzanite is a thoroughly modern discovery, brought to global prominence in the latter half of the 20th century. Zircon, often mistaken for cubic zirconia, is one of the oldest minerals on Earth, yet its history as a treasured gem is equally profound. This article will explore the history, geological origins, gemological properties, and symbolism of Tanzanite, Turquoise, and Zircon, providing a detailed guide for those connected to this powerful date.
History and Lore of the December 31 Birthstones
The cultural significance of the December 31 birthstones is a study in contrasts, reflecting the vast differences in their origins and the eras in which they were discovered and revered.
Turquoise: An Ancient Talisman
Turquoise is arguably the most historically significant of the three. Its name itself tells a story of trade and geography. The stone was found in Persia and along the Sinai Peninsula and was transported to Europe through the gem markets of Constantinople, Turkey. This path of commerce gave the gem its name, derived from the French pierre turquoise, meaning "Turkish stone."
From the earliest times, Turquoise was a favored material for amulets. Its relative softness made it easy to cut into various shapes and to inscribe, enhancing its role as a protective charm. It was widely believed to possess the power to ward off danger and bring good fortune. Lore surrounding Turquoise suggested it could warn its wearer of approaching illness or danger by becoming pale, acting as a living barometer for one's health. The stone was particularly prized by lovers and married couples, who saw it as a protector of relationships. A gift of Turquoise was thought to preserve friendship and ensure fidelity.
This protective symbolism was not confined to the Old World. In Tibet, Turquoise was considered a birthstone of fortune, health, and success, so valued that it was often used as a form of currency. For the ancient Incas and Mayas, Turquoise was a sacred offering to their gods. Similarly, Native American cultures of the Southwest have long associated the gemstone with youth and strength, incorporating it into their intricate jewelry and ceremonial objects.
Tanzanite: A Modern Phenomenon
Tanzanite is the newest addition to the birthstone family. It was first identified in 1967 in the Merelani Hills of Tanzania, making it one of the most recent major gemstone discoveries. A variety of the mineral zoisite, Tanzanite's rise to fame was meteoric, largely due to its captivating color and the marketing efforts of a major jewelry company.
Despite its modern recognition, its connection to the end of the year is a relatively new construct. Its vibrant blue and violet hues, which exhibit color-changing properties under different lighting conditions (a phenomenon known as pleochroism), quickly captured the attention of jewelers and collectors. While it lacks the ancient lore of Turquoise or Zircon, its narrative is one of transformation and new beginnings, a fitting theme for the last day of the year and the promise of a new one. Its association with luxury and modernity makes it a popular choice for contemporary jewelry designs.
Zircon: The Old World Sparkle
Zircon is one of the oldest minerals on Earth, with zircon crystals found in Australia dating back over 4.4 billion years. As a gemstone, its history is equally ancient. For centuries, Zircon has been prized for its exceptional brilliance and fire, which rivals that of diamond. It was a popular gem in the Middle Ages and was believed to bring honor and prosperity to its wearer.
Throughout history, Zircon has been confused with other stones, most notably the synthetic cubic zirconia of the late 20th century, which has unfortunately overshadowed its natural beauty in the public mind. However, for the discerning enthusiast, natural Zircon remains a gem of significant value and historical importance. Its association with wisdom and clarity has made it a stone of intellect and spiritual grounding.
Geological Formation and Global Sources
The origins of these three gemstones are as diverse as their histories. Each is formed under unique geological conditions and is sourced from specific, often limited, locations around the globe.
Turquoise is a secondary mineral that forms when water containing copper and aluminum seeps through rocks. This process can take millions of years, often occurring in arid regions where the water table has evaporated, leaving behind deposits of the gem. Major sources for Turquoise include Iran (historically the source of the finest "Persian Turquoise"), the Southwestern United States (particularly Arizona and New Mexico), China, and Egypt. The appearance of Turquoise, including its color and the presence of a distinctive "matrix" (the host rock veining), varies significantly based on its geographic origin.
Tanzanite has a remarkably exclusive origin. It is found in only one place on Earth: the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. The geological conditions required for its formation are exceptionally rare. It is a variety of zoisite that was subjected to intense heat and pressure during the formation of the East African Rift, which caused the chromium atoms responsible for its blue coloration to enter its crystal structure. This limited source contributes to its value and the ongoing concern about the longevity of its supply.
Zircon is a zirconium silicate mineral that forms within igneous and metamorphic rocks. It is a primary mineral, meaning it crystallizes directly from magma. It is found in a wide variety of geological settings and is one of the most durable minerals, often surviving through erosion to be deposited in sedimentary placer deposits. Major sources for gem-quality Zircon include Cambodia, Sri Lanka, Thailand, Australia, and parts of Africa. The stone is heat-treated to enhance its color, a stable and permanent treatment that is standard practice in the industry.
Gemological Properties
Understanding the physical and chemical properties of a gemstone is crucial for both appreciation and practical care. The December 31 birthstones exhibit a wide range of characteristics.
| Property | Tanzanite | Turquoise | Zircon |
|---|---|---|---|
| Mineral Species | Zoisite | Hydrated phosphate of copper and aluminum | Zircon |
| Chemical Formula | Ca₂(Al,OH)₂Si₃O₁₀ | CuAl₆(PO₄)₄(OH)₈·4H₂O | ZrSiO₄ |
| Hardness (Mohs Scale) | 6.5 - 7 | 5 - 6 | 6.5 - 7.5 |
| Crystal System | Orthorhombic | Triclinic | Tetragonal |
| Refractive Index | 1.691 - 1.700 | 1.610 - 1.650 | 1.92 - 1.98 |
| Key Characteristic | Strong pleochroism (color change) | Porosity, often has a matrix | High brilliance and fire (dispersion) |
Tanzanite is known for its strong pleochroism, displaying different shades of blue, violet, and burgundy depending on the crystal orientation. With a Mohs hardness of 6.5 to 7, it is moderately durable but requires care to avoid scratches and impacts. Its refractive index is relatively low for a colored stone, contributing to a subtle rather than fiery brilliance.
Turquoise is a relatively soft and porous gemstone, with a hardness of only 5 to 6 on the Mohs scale. This porosity means it can absorb oils and chemicals, which can alter its color over time. Many Turquoise stones on the market are "stabilized," meaning they have been treated with resins or polymers to increase their durability and prevent color change. This is a common and accepted practice in the industry.
Zircon is the hardest of the three, with a Mohs hardness ranging from 6.5 to 7.5. Its most defining gemological property is its high refractive index and high dispersion, which give it exceptional brilliance and "fire" that can rival a diamond. It is a highly refractive gemstone, making it extremely brilliant when cut well. However, Zircon can be brittle due to its crystal structure, making it susceptible to chipping if struck hard.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, gemstones have been imbued with symbolic meaning and metaphysical powers. The December 31 birthstones carry distinct and powerful associations.
Turquoise is universally recognized as a stone of protection, good fortune, and friendship. It is believed to be a calming stone that can balance mood swings and bring inner peace. Its association with the throat chakra in modern crystal healing makes it a stone of communication, helping the wearer to speak their truth clearly and kindly. The lore of its color-changing ability to warn of danger has cemented its reputation as a vigilant guardian.
Tanzanite, as a modern discovery, has been assigned metaphysical properties that align with its color and origin. It is widely associated with transformation, new beginnings, and spiritual awakening. Its connection to the throat and crown chakras suggests it aids in higher consciousness and intuition. For those born on December 31, it can symbolize the transition from one year to the next, encouraging the release of the old and the embrace of the new.
Zircon is a stone of clarity, wisdom, and balance. It is believed to help its wearer achieve a state of spiritual and mental equilibrium. Historically, it was thought to promote honor and prosperity. In modern metaphysical beliefs, Zircon is used to stimulate the root chakra, providing a sense of grounding and stability. It is also associated with self-esteem and a more joyful, confident outlook on life.
Care and Cleaning
Due to their differing physical properties, the three December 31 birthstones require distinct care regimens to maintain their beauty and integrity.
Tanzanite: Given its moderate hardness and sensitivity to heat and shock, Tanzanite requires gentle handling. It should be cleaned using only a soft cloth, warm water, and a mild soap. It is crucial to avoid ultrasonic cleaners and steam cleaners, as the vibrations and high temperatures can cause fractures or damage the stone. Tanzanite should be stored separately in a soft cloth or padded jewelry box to prevent it from being scratched by other gems. It should also be protected from prolonged exposure to direct sunlight, which can potentially cause its color to fade over time.
Turquoise: As a soft and porous stone, Turquoise is the most delicate of the trio. It should be cleaned with a soft, dry cloth. If necessary, a damp cloth with mild soap can be used, but the stone must be dried immediately and thoroughly. Like Tanzanite, it should never be placed in an ultrasonic or steam cleaner. Turquoise is particularly sensitive to chemicals, including cosmetics, lotions, and perfumes, which can damage the stone's surface. For stabilized Turquoise, harsh chemicals could strip away the stabilizing resins, leading to a dull or discolored appearance. It is best stored in a cool, dry place away from humidity.
Zircon: Zircon is the most durable of the December stones and is relatively easy to care for. It can be safely cleaned with warm water, mild soap, and a soft brush. It is also generally safe to use an ultrasonic cleaner, though caution is advised if the stone has any fractures or inclusions. Zircon is resistant to most chemicals and can withstand the rigors of everyday wear, though its brittleness means it should be protected from hard blows. It does not require special treatments to maintain its color and is resistant to fading.
Conclusion
The birthstones for December 31—Tanzanite, Turquoise, and Zircon—form a compelling triad that represents the full spectrum of the gemstone experience. They span the breadth of human history, from the ancient amulets of Persia and Tibet to a 20th-century discovery at the foot of Mount Kilimanjaro, and the billion-year-old crystals that hold the Earth's history within them. Their colors range from the soft, sky blue of Turquoise to the deep, shifting violet-blue of Tanzanite and the brilliant, diamond-like sparkle of Zircon.
For the individual born on this date, the choice of a birthstone is not merely a matter of color preference but an opportunity to connect with a rich tapestry of geology, history, and symbolism. Whether one is drawn to the protective power of Turquoise, the transformative energy of Tanzanite, or the clarifying wisdom of Zircon, each stone offers a unique and meaningful connection to the natural world and the cycles of time. Together, they are a fitting tribute to the final day of the year, embodying both the weight of history and the promise of the future.