The month of December is uniquely represented in the modern birthstone list by a trio of distinct and captivating gemstones: Turquoise, Tanzanite, and Zircon. While Zircon is the traditional third option, the provided materials focus extensively on the allure of Turquoise and Tanzanite, showcasing their prominent role in contemporary jewelry. These two gems offer a remarkable spectrum of color, from the serene, sky-blue of Turquoise to the vibrant, violet-blue hues of Tanzanite. Their selection for the winter month speaks to a desire for stones that provide both a cool, refreshing aesthetic and a connection to ancient history and modern discovery. This article delves into the unique characteristics, origins, and cultural significance of these two celebrated December birthstones, providing a comprehensive guide for enthusiasts, collectors, and anyone captivated by their beauty.
The Enduring Legacy of Turquoise
Turquoise is one of the oldest known gemstones, revered by civilizations across the globe for millennia. Its name is derived from the French phrase pierre turquoise, meaning "Turkish stone," as the gem was first brought to Europe from Turkey via Persian trade routes. However, its history stretches far beyond this, with artifacts adorned with turquoise unearthed in ancient Egypt, Mesopotamia, and China. This gem has been a symbol of wealth, protection, and spiritual grounding for thousands of years. In the American Southwest, turquoise holds deep cultural significance for Native American tribes such as the Navajo, Zuni, and Pueblo, who have incorporated it into their intricate jewelry and spiritual practices for centuries. Its status as a December birthstone is a relatively modern designation, solidified by standardized lists in the early 20th century, but its association with winter skies and protective qualities is ancient.
Geological Formation and Sources
Turquoise is a hydrous phosphate of copper and aluminum, forming in arid regions where acidic, copper-rich groundwater seeps through aluminum-bearing rocks. This process occurs over millions of years, creating vein-fillings or nodules in the host rock. The presence of copper is responsible for the gem's iconic blue to greenish-blue color, while traces of iron can shift the hue toward green. The finest quality turquoise is often found in "dry mining" conditions, where the gem is extracted from the host rock without the use of water, preserving its natural, unaltered state.
Historically, the most significant sources of turquoise have been in Iran (formerly Persia), which has been producing gem-quality material for over 2,000 years. Persian turquoise is renowned for its pure, sky-blue color and is often free from the matrix, or host rock, that can be visible in other varieties. In the United States, the Southwest is a major source, with notable mines in Arizona (like the famous Sleeping Beauty mine), Nevada (Lander Blue), and New Mexico. These sources produce a wide array of colors and matrix patterns, contributing to the diverse aesthetic of American turquoise jewelry.
Gemological Properties and Identification
Turquoise is a relatively soft and porous gemstone, which influences both its appearance and its care requirements.
- Hardness: It typically registers between 5 and 6 on the Mohs scale of hardness. This makes it susceptible to scratching and requires careful handling to avoid damage from harder materials like quartz or diamond.
- Color: The color range spans from sky blue and azure to blue-green and "apple green." The most prized color is a strong, "robin's egg" blue, often referred to as "sky blue."
- Clarity and Structure: Turquoise is rarely transparent and is typically cut en cabochon (a smooth, polished dome) to showcase its color. It often contains a matrix of the host rock, which appears as a web of brown, black, or golden veins. The pattern and color of the matrix can significantly affect the stone's value.
- Stability: The gem is sensitive to heat, chemicals, and even prolonged exposure to skin oils and cosmetics, which can cause discoloration. It is also porous, meaning it can absorb liquids that may alter its color.
Symbolism and Metaphysical Beliefs
Across cultures, turquoise has been regarded as a sacred stone of protection, wisdom, and good fortune. It was believed to change color to warn its wearer of impending danger or illness. Ancient Persian talismans featured turquoise to ward off the "evil eye," while Tibetan shamans used it as a conduit for spiritual connection and healing. In Native American culture, it is considered a living stone, a direct link between the earth and the sky, bringing peace and balance. For the December-born, turquoise is said to promote tranquility, creative self-expression, and the alignment of all chakras, fostering a sense of holistic well-being.
Care and Cleaning
Due to its porosity and relative softness, turquoise requires specific care. It should be protected from harsh chemicals, including perfumes, lotions, and household cleaners. To clean it, simply use a soft, dry cloth. Avoid ultrasonic cleaners, steam cleaners, and soaking the stone in water, as this can weaken the gem and damage any stabilizing treatments or porous areas. It is best to store turquoise jewelry separately to prevent it from being scratched by other gems.
Tanzanite: The Modern Marvel
In stark contrast to the ancient history of turquoise, tanzanite is a distinctly modern gemstone, discovered just over half a century ago. Its story is one of geological serendipity and brilliant marketing, quickly elevating it to the ranks of the world's most sought-after colored gems. Its rarity and unique color have made it a favorite for fine jewelry and a proud representative of the December birthstone trio.
Discovery and Geological Formation
Tanzanite was discovered in 1967 in the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. The gemologist who first identified it, Manuel de Souza, initially thought he had found an olivine deposit, but its unique blue crystals soon revealed a new mineral species. Geologically, tanzanite is a variety of the mineral zoisite, and its formation is an exceptionally rare occurrence. It is believed that the unique geological conditions required for its creation—a combination of specific temperatures, pressures, and the presence of the element vanadium—occurred only in this single, small area of the world, making it thousands of times rarer than diamond.
Gemological Properties and Identification
Tanzanite is celebrated for its extraordinary color and impressive clarity, which make it a spectacular gem for faceted jewelry.
- Hardness: On the Mohs scale, tanzanite registers between 6.5 and 7. This makes it more durable than turquoise but still requires reasonable care to prevent scratching.
- Color: Its most defining characteristic is its vibrant, saturated color, which ranges from a pure, ultramarine blue to a deep violet. The gem is strongly pleochroic, meaning it displays different colors when viewed from different angles—typically blue, violet, and a reddish-brownish hue. Master cutters orient the stone to showcase the dominant blue-violet face-up color.
- Clarity: High-quality tanzanite is typically "eye-clean," with few to no visible inclusions. This exceptional clarity enhances its brilliance and appeal.
- Treatments: Nearly all tanzanite on the market is heat-treated. The rough material is heated to a temperature of approximately 375-400°C (707-752°F) to remove the brownish tones and produce the desirable blue and violet colors. This treatment is stable and permanent and is considered an essential part of the gem's production process, not a disclosure of a treated stone.
Symbolism and Metaphysical Beliefs
As a modern gem, tanzanite has quickly developed its own lore. It is often called the "stone of transformation" and is believed to facilitate a higher consciousness, intuition, and spiritual perception. It is associated with the throat and third-eye chakras, promoting clear, truthful communication and psychic abilities. For those born in December, tanzanite is said to bring calmness and composure, encouraging a balanced approach to life's challenges while fostering a unique, creative perspective.
Care and Cleaning
While more durable than turquoise, tanzanite's relative softness and strong pleochroism require careful handling. It is susceptible to scratching and should be stored carefully. The gem can also be sensitive to rapid temperature changes, which could cause fracturing. The best method for cleaning tanzanite is warm water, a mild soap, and a soft brush. As with turquoise, ultrasonic and steam cleaners should be avoided due to the risk of damage.
Conclusion
Turquoise and Tanzanite, the two primary modern birthstones for December, represent a fascinating duality in the world of gemstones. Turquoise connects us to a deep, ancient past, its earthy tones and protective lore resonating with a timeless sense of security and natural beauty. Tanzanite, on the other hand, is a product of modern discovery, its brilliant, otherworldly color and remarkable rarity capturing the spirit of transformation and innovation. Together, they offer the December-born a choice between enduring tradition and contemporary elegance. Whether one is drawn to the calming, sky-blue of an ancient talisman or the vibrant, violet fire of a geological marvel, these gems provide a meaningful and beautiful link to the natural world and its enduring mysteries.