December 31st, the final day of the calendar year, is uniquely endowed with three distinct birthstones: Tanzanite, Turquoise, and Zircon. Each of these gems represents a different facet of geological wonder, historical narrative, and cultural symbolism. For individuals born on this day, these stones offer a rich palette of colors, properties, and lore to explore. This article provides a comprehensive examination of these three remarkable gemstones, delving into their histories, geological origins, gemological characteristics, and the metaphysical beliefs that have surrounded them through the ages. By understanding the unique attributes of Tanzanite, Turquoise, and Zircon, one can appreciate their significance not only as personal adornments but also as carriers of deep cultural and symbolic meaning.
Historical Use and Cultural Significance
The historical journey of each of these December 31st birthstones is as varied as their colors, ranging from ancient talismans to modern celebrity favorites.
Tanzanite: A Modern Discovery with Ancient Roots
Tanzanite is the most recent addition to the birthstone calendar. It was first identified in 1967 in the Merelani Hills of Tanzania. Although it is a modern gem in terms of commercial recognition, its vibrant blue and violet hues quickly captured the attention of jewelers and collectors. The gemstone was named after its country of origin by the renowned jewelry house Tiffany & Co., which introduced it to the global market in the late 1960s. Despite its recent discovery, Tanzanite has rapidly embedded itself in popular culture. It is a favorite among celebrities, with figures like Anne Hathaway, Cate Blanchett, and Sarah Jessica Parker being photographed wearing Tanzanite jewelry. A notable instance of its modern appeal is when Jay Z presented his wife, Beyoncé, with a Tanzanite ring to celebrate the birth of their daughter, Blue Ivy.
Turquoise: An Ancient Amulet of Protection
Turquoise possesses a far more ancient and widespread history. Its name derives from the French pierre turquoise, meaning "Turkish stone," reflecting its trade route through Constantinople (modern-day Istanbul) from its original sources in Persia and the Sinai Peninsula. From the earliest times, turquoise was a favored gem for amulets. It was relatively easy to cut into different shapes and make inscriptions on, which enhanced its role as a protective talisman. The stone was believed to offer protection against danger and bring good fortune. It was especially prized by lovers and married couples, as it was thought to protect relationships and preserve friendship when given as a gift. A popular belief held that turquoise could warn its wearer of approaching illness or danger by becoming pale.
Various cultures attributed profound significance to turquoise. Tibetans considered it a birthstone of fortune, health, and success, and it was so valued that it was often used as currency. For the Ancient Incas and Mayas, turquoise was a sacred offering to their gods. Among Native Americans of the Southwest, the gemstone was associated with youth and strength.
Zircon: A Gem of Ancient Lore and Modern Durability
Zircon is one of the oldest minerals on Earth, with some specimens dating back billions of years. Its historical use is also ancient. In Europe, it was used as an amulet against the Black Death plague. In India, it was believed that zircon had greater potency if set in gold. While its history is long, its status as a December birthstone is a more modern classification, sharing the month with Tanzanite and Turquoise.
Geological Formation and Sources
The origins of these gemstones are as diverse as their histories, with each forming under unique geological conditions and being mined from specific regions of the world.
Tanzanite: A Single Source Phenomenon
Tanzanite’s geological story is one of remarkable rarity. It is a variety of the mineral zoisite and forms through a specific metamorphic process. The only known commercial source of Tanzanite is a small, four-square-kilometer mining area in the Merelani Hills of Tanzania, near the base of Mount Kilimanjaro. This extreme geographic limitation makes Tanzanite significantly rarer than diamond. The rough stones are often heat-treated to remove unwanted brown and burgundy hues, revealing the prized blue and violet colors for which the gem is known.
Turquoise: A Global Mineral with Distinct Localities
Turquoise is a hydrated phosphate of copper and aluminum. It forms in arid regions where acidic, copper-rich groundwater seeps through pre-existing rocks, depositing turquoise in nodules and veins. Historically, it was found in Persia (modern-day Iran) and along the Sinai Peninsula. Today, significant deposits are also found in the Southwestern United States, Egypt, and China. The color of turquoise varies widely based on its copper (blue) and iron (orange/brown) content, leading to a spectrum from sky blue to greenish-blue. Many turquoise stones on the market are "stabilized," meaning they are impregnated with resins or oils to enhance their durability and color.
Zircon: A Widespread and Durable Mineral
Zircon (not to be confused with synthetic cubic zirconia) is a zirconium silicate mineral. It is a common accessory mineral found in many types of rocks, but gem-quality zircon is rarer. Australia and South Africa together produce approximately 70% of the world's zircon gemstones. Other notable sources include Sri Lanka, India, and Myanmar (Burma). Zircon forms in igneous rocks, particularly in granites and pegmatites, and is also found in metamorphic rocks. It is one of the hardest minerals, contributing to its durability as a gemstone.
Gemological Properties
Understanding the physical and chemical properties of these gems is essential for their identification, care, and appreciation.
Tanzanite
Tanzanite is a variety of zoisite, a mineral belonging to the epidote group. Its chemical formula is Ca₂Al₃(SiO₄)₃(OH), with traces of vanadium and chromium causing its blue and violet coloration. It has a hardness of 6.5 to 7 on the Mohs scale, making it moderately durable but susceptible to scratching if not handled with care. Its most celebrated characteristic is its pleochroism—the ability to display different colors when viewed from different crystal directions. Under natural light, it can appear blue, violet, or even burgundy. Under standard artificial light, it often appears violet, while under fluorescent light, it appears blue. This color-changing property is a key gemological identifier.
Turquoise
Turquoise is a phosphate mineral with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. Its color ranges from blue to green, determined by the copper (blue) and iron (green) content within its structure. Turquoise has a hardness of 5 to 6 on the Mohs scale, making it relatively soft. It is also porous, which can affect its durability and color stability. The gem has a waxy to vitreous luster and is typically cut into cabochons to best display its color and any matrix (the host rock) inclusions.
Zircon
Zircon is a zirconium silicate with the chemical formula ZrSiO₄. It is a highly durable gemstone, with a hardness of 7.5 on the Mohs scale, and it has no cleavage, making it resistant to breaking. Its high refractive index (1.92-2.01) gives it a brilliant, diamond-like sparkle, and its high dispersion (0.039) results in strong fire, or flashes of spectral color. Zircon occurs in a variety of colors, including blue, green, yellow, brown, and red. Blue zircon is often heat-treated to achieve its vibrant color, similar to the treatment of Tanzanite.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, these gemstones are steeped in symbolic meaning and metaphysical lore, which has been passed down through generations.
Tanzanite
As a modern gem, Tanzanite's metaphysical beliefs are more contemporary, often linked to its unique color-changing ability. It is sometimes associated with transformation, intuition, and spiritual awakening. Its rarity and connection to a single location in Tanzania have also led to it being seen as a stone of uniqueness and individuality.
Turquoise
Turquoise is arguably one of the most symbolically charged gemstones in history. It has been universally regarded as a stone of protection, healing, and good fortune. Its ability to change color was seen as a direct communication from the stone, warning of danger or illness. It is also deeply connected to love and friendship, making it a popular gift for relationships. In many cultures, turquoise is believed to connect the wearer to the earth and sky, promoting balance and grounding.
Zircon
Zircon has a long history of being used as a protective talisman. It was believed to promote honor, purity, and wisdom. In medieval times, it was thought to induce sleep and ward off evil spirits. Its association with the planet Saturn in some astrological traditions links it to discipline and responsibility. The gem is also said to boost self-confidence and aid in spiritual growth.
Care and Cleaning
Proper care is essential to maintain the beauty and integrity of these gemstones, as their physical properties dictate their vulnerabilities.
Tanzanite
Tanzanite requires gentle handling due to its moderate hardness (6.5-7) and sensitivity to heat and pressure. It should be cleaned with a soft cloth, warm water, and a mild soap. Avoid harsh chemicals, ultrasonic cleaners, and steam cleaners, as these can damage the stone. It is also sensitive to extreme temperatures and direct sunlight, which can cause fading. To prevent scratches, store Tanzanite separately from other jewelry.
Turquoise
As a soft and porous stone (hardness 5-6), turquoise needs careful maintenance. Clean it with a soft, dry cloth. If necessary, use a damp cloth with mild soap, but avoid soaking the stone, as it can absorb water and become discolored. Keep turquoise away from chemicals, cosmetics, and excessive moisture. Since many turquoise stones are stabilized with resins or oils, avoid any cleaning methods that could strip these treatments. Store it in a cool, dry place.
Zircon
Zircon is the most durable of the three December 31st birthstones (hardness 7.5). It can be cleaned with a soft brush, warm water, and mild soap. It is also safe to use ultrasonic and steam cleaners for Zircon, provided the stone is not fractured. However, it is always advisable to check with a professional jeweler before using such methods, especially for stones that may have been treated or have inclusions.
Conclusion
The birthstones of December 31st—Tanzanite, Turquoise, and Zircon—offer a compelling triad of gemological diversity. Tanzanite, the modern marvel from Tanzania, captivates with its color-changing pleochroism and celebrity appeal. Turquoise, the ancient amulet of protection, carries a deep history of cultural significance across continents, from Persia to the American Southwest. Zircon, the durable and brilliant mineral, provides a diamond-like sparkle and a legacy of protective lore. Together, they represent a spectrum of colors, hardness, and historical narratives. For those born on the final day of the year, these stones provide not only beautiful adornments but also a tangible connection to the earth’s geology and humanity’s enduring fascination with the symbolic power of gemstones. Understanding their properties, origins, and care ensures that their legacy can be appreciated for generations to come.