The month of December is uniquely gifted with a trio of captivating birthstones: turquoise, tanzanite, and blue zircon. Each stone possesses a distinct character, from the ancient, sky-blue allure of turquoise to the modern, vivid violet-blue of tanzanite and the brilliant, fiery sparkle of blue zircon. Together, they embody the crisp beauty of winter, offering a spectrum of color that ranges from serene to dazzling. As symbols of calm, clarity, and communication, these gemstones are not only visually striking but also rich with personal and cultural significance. This article explores the geological origins, gemological properties, historical lore, and contemporary symbolism of these three December birthstones, providing a comprehensive guide for enthusiasts, collectors, and those seeking the perfect meaningful gift.
History and Lore: A Journey Through Time and Culture
The history of December's birthstones is a tapestry woven from ancient trade routes, modern discovery, and enduring cultural beliefs.
Turquoise is arguably the oldest of the three, with a history spanning millennia. Its name is derived from the French pierre turquoise, meaning "Turkish stone," as it was originally brought to Europe from the Middle East via Turkey. However, its use predates these trade routes significantly. Ancient civilizations, including the Egyptians, Persians, and Native Americans, held turquoise in high esteem. The Egyptians mined it as early as 6000 BCE, and it was often used in elaborate jewelry and amulets, believed to offer protection and connect the wearer to the spiritual realm. For many Native American tribes, particularly in the Southwestern United States, turquoise is sacred, representing the sky and water, and is integral to their art and ceremonies. Its status as a December birthstone is deeply rooted in these ancient traditions, where it was seen as a talisman against harm and a bringer of good fortune.
In contrast, tanzanite is a newcomer to the gemstone world, discovered only in the 20th century. Its story began in 1967 in the Merelani Hills of Tanzania, near the base of Mount Kilimanjaro. A local Maasai herder, Ali Juuyawatu, found translucent blue crystals in the area, which were later identified as a new variety of the mineral zoisite. The gem was named after its country of origin by Tiffany & Co., which introduced it to the global market in 1968, marketing it as a "gemstone of a generation." Its rapid rise to fame and inclusion as an official December birthstone in 2002 by the American Gem Trade Association (AGTA) is a testament to its modern appeal. While it lacks the ancient lore of turquoise, tanzanite is often associated with transformation and new beginnings, reflecting its recent discovery and its vivid, otherworldly color.
Blue zircon, while often confused with the synthetic cubic zirconia, is a natural gemstone with a history that dates back to the Middle Ages. The name "zircon" is derived from the Persian word zargun, meaning "gold-colored," though blue zircon is prized for its cool, icy hues. In medieval Europe, blue zircon was believed to possess properties that could induce sleep, promote prosperity, and ward off evil spirits. It was also a popular gem for royalty and the elite. However, its journey to becoming a December birthstone was more complex. For much of the 20th century, blue zircon was not widely recognized as a birthstone, but in 1952, it was added to the official list of birthstones by the American Gem Trade Association, solidifying its place as a modern choice for December. Its brilliance and fire, which rival that of diamonds, have made it a favorite among jewelers and collectors seeking a vibrant and affordable alternative.
Geological Formation and Sources
The formation and sourcing of these three gemstones are as diverse as their appearances, reflecting their unique geological histories.
Turquoise is a secondary mineral that forms in arid regions where acidic, copper-rich groundwater interacts with aluminum- and phosphorus-bearing rocks. This process occurs over millions of years, creating veins and nodules in host rocks. The most renowned sources include the Persian (Iranian) turquoise, historically mined in the Nishapur region, which is celebrated for its uniform sky-blue color. In the United States, significant deposits are found in Arizona (e.g., Sleeping Beauty, Kingman), New Mexico, and Nevada. The quality of turquoise is heavily influenced by its matrix—the host rock that remains embedded in the stone—creating unique patterns that are highly valued in jewelry.
Tanzanite is found exclusively in a small, four-square-kilometer area in the Merelani Hills of Tanzania, making it one of the rarest gemstones on Earth. It forms in the presence of heat and pressure from metamorphic processes involving the mineral zoisite. The gem's distinctive violet-blue color is the result of trace amounts of vanadium, which becomes apparent only after the stone is heated. This treatment is standard in the industry and enhances the stone's color stability. Due to its single-source origin, tanzanite is considered a "generation gemstone," with experts predicting that supplies may be exhausted within a few decades, adding to its allure and value.
Blue zircon is a mineral that forms in igneous and metamorphic rocks, particularly in granitic pegmatites. It is a common accessory mineral but gem-quality crystals are rare. Major sources include Cambodia, Myanmar (Burma), and Sri Lanka, with some deposits in Australia and Norway. The blue color in zircon is typically achieved through heat treatment of brown zircon crystals, a process that has been used for centuries to enhance the stone's beauty. Natural blue zircon is exceptionally rare, and most blue zircon on the market is heat-treated. The gem's brilliance is due to its high refractive index and strong dispersion, which gives it a fiery sparkle.
Gemological Properties
Understanding the physical and chemical properties of these gemstones is crucial for their identification, care, and valuation. The table below summarizes key gemological characteristics for turquoise, tanzanite, and blue zircon.
| Property | Turquoise | Tanzanite | Blue Zircon |
|---|---|---|---|
| Chemical Formula | CuAl₆(PO₄)₄(OH)₈·4H₂O | Ca₂Al₃(SiO₄)₃(OH) | ZrSiO₄ |
| Crystal System | Triclinic | Orthorhombic | Tetragonal |
| Hardness (Mohs) | 5 - 6 | 6.5 - 7 | 6.5 - 7.5 |
| Refractive Index | 1.61 - 1.65 | 1.69 - 1.70 | 1.92 - 2.01 |
| Specific Gravity | 2.6 - 2.9 | 3.35 | 4.6 - 4.7 |
| Luster | Waxy to subvitreous | Vitreous | Adamantine to vitreous |
| Color | Sky blue to greenish-blue | Blue-violet (after heating) | Blue, greenish-blue |
| Transparency | Opaque to translucent | Transparent to translucent | Transparent |
Turquoise is an opaque to translucent mineral with a hardness of 5 to 6 on the Mohs scale, making it relatively soft and susceptible to scratching and chemicals. Its waxy luster and characteristic color come from copper and iron impurities. The presence of a matrix (host rock) is common and can affect durability. High-quality turquoise is uniform in color, though this is rare in natural stones.
Tanzanite is a transparent to translucent gem with a hardness of 6.5 to 7, making it suitable for most jewelry but requiring care against sharp blows. Its most notable feature is its strong trichroism, displaying three different colors: blue, violet, and burgundy, depending on the crystal orientation. The violet-blue hue is the most sought-after. It has a vitreous luster and a refractive index of 1.69 to 1.70. Most tanzanite is heated to stabilize the color and remove brownish tones, a standard and permanent treatment.
Blue zircon is a transparent gem with a high refractive index (1.92 - 2.01) and strong dispersion, giving it exceptional brilliance and fire, often compared to diamonds. Its hardness of 6.5 to 7.5 makes it durable enough for jewelry, though it can be brittle due to its tetragonal crystal structure. Natural blue zircon is rare; most commercial blue zircon is heat-treated brown zircon. The gem's color ranges from light to deep blue, with the most valued hues being vivid and saturated.
Symbolism and Metaphysical Beliefs
Each of the December birthstones carries its own set of symbolic meanings and metaphysical beliefs, often rooted in ancient traditions or modern interpretations.
Turquoise is universally regarded as a stone of protection, wisdom, and good fortune. In many cultures, it is believed to ward off negative energy, promote emotional balance, and enhance communication. Its connection to the sky and water makes it a symbol of tranquility and spiritual grounding. For Native Americans, it is a sacred stone that represents life and the universe. In modern crystal healing, turquoise is associated with the throat chakra, supporting honest expression and clarity.
Tanzanite, as a newly discovered gem, lacks ancient lore but has quickly accumulated modern metaphysical associations. It is often linked to transformation, intuition, and spiritual awakening. Its unique color is said to stimulate the higher mind and facilitate a connection to one's higher self. Some believe tanzanite can promote calmness and relieve stress, making it a stone for meditation and inner peace. Its rarity is also seen as a symbol of uniqueness and individuality.
Blue zircon has historical associations with prosperity, honor, and purity. In medieval times, it was thought to induce sleep, ward off evil, and bring wisdom. Today, it is often associated with clarity of thought, emotional balance, and spiritual grounding. Its brilliant sparkle is believed to attract positive energy and enhance self-confidence. Some metaphysical practitioners associate blue zircon with the throat and third eye chakras, promoting clear communication and intuitive insight.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones, given their distinct physical properties.
Turquoise, with its moderate hardness and porous nature, requires gentle handling. It should be protected from prolonged exposure to water, oils, and chemicals, which can cause discoloration or damage. Clean turquoise jewelry with a soft, dry cloth. Avoid ultrasonic cleaners and steam, as they can harm the stone. Store turquoise separately to prevent scratching from harder gems.
Tanzanite is relatively durable but should be protected from sharp blows and extreme temperature changes, which can cause cleavage. It is best cleaned with warm, soapy water and a soft brush. Ultrasonic and steam cleaners are not recommended, as they can damage the stone or its treatments. Due to its popularity in rings, it's advisable to set tanzanite in protective settings for daily wear.
Blue zircon is hard but can be brittle. It is susceptible to chipping if struck, so protective settings are recommended for rings. Clean blue zircon with warm, soapy water and a soft brush. Avoid sudden temperature changes and harsh chemicals. Ultrasonic cleaners are generally safe, but caution is advised due to potential inclusions. Store blue zircon jewelry separately to prevent scratches from other stones.
Conclusion
The December birthstones—turquoise, tanzanite, and blue zircon—offer a remarkable diversity of color, history, and meaning. From the ancient, protective qualities of turquoise to the modern, transformative allure of tanzanite and the brilliant, fiery sparkle of blue zircon, each stone provides a unique way to celebrate the winter month. Their gemological properties, from turquoise's soft opacity to zircon's diamond-like fire, dictate specific care requirements, ensuring their beauty endures for generations. Whether chosen for their historical significance, metaphysical beliefs, or simply their stunning appearance, these gemstones remain cherished symbols of personal identity and timeless elegance. For collectors and gift-givers alike, the December trio represents a perfect convergence of nature's artistry and human tradition.