For those born on December 16, the birthstone selection is not a singular choice but a rich triad of distinct gemstones: Tanzanite, Turquoise, and Zircon. These three gems, though varied in their geological origins, physical properties, and historical narratives, are united by their shared association with the month of December and their captivating blue hues. Each stone offers a unique profile, from the ancient protective lore of Turquoise to the modern allure of Tanzanite and the exceptional brilliance of Zircon. This article provides a comprehensive exploration of these three gemstones, delving into their history, geological formation, gemological properties, and symbolic meanings, drawing exclusively from established sources to guide gemstone enthusiasts, jewelry buyers, and students of gemology.
The inclusion of multiple stones for December reflects a modern tradition that values both heritage and accessibility. While Turquoise stands as the traditional and ancient birthstone, Tanzanite and Zircon have been officially recognized as modern alternatives, offering a spectrum of color, durability, and price points. This guide will dissect the individual characteristics of each stone, allowing for an informed appreciation of why this specific date is so uniquely endowed in the world of birthstones.
History and Lore
The historical narratives of Tanzanite, Turquoise, and Zircon span millennia and continents, telling stories of ancient rituals, royal adornment, and modern discovery.
Turquoise: The Ancient Talisman
Turquoise is unequivocally the oldest and most traditional of the December birthstones, with a history stretching back thousands of years. Its use is deeply embedded in the annals of ancient civilizations. Pharaohs and other rulers of ancient Egypt adorned themselves with this vibrant blue-green stone, while Chinese artisans were carving turquoise more than 3,000 years ago. The gemstone was not merely decorative; it was believed to possess potent beneficial powers, including the ability to guarantee health and good fortune.
A significant chapter in Turquoise's lore involves its perceived protective qualities. From the 13th century onward, it was widely believed to safeguard the wearer from falling, particularly from horses, and was thought to shatter into several pieces as a warning of an impending disaster. This attribute made it a favored talisman among warriors and travelers. Hindu mystics held a different, yet equally auspicious, belief: that seeing a turquoise after beholding the new moon would ensure fantastic wealth. In the Americas, the Apache people believed turquoise could be found by following a rainbow to its end, imbuing the stone with the magic of the natural world. Today, Persian turquoise is considered the most prized variety, celebrated for its vivid, evenly saturated sky-blue color and minimal to nonexistent matrix, the dark veining that often runs through the stone. Another highly sought-after variety is Sleeping Beauty Turquoise, known for its pure, robin's-egg blue color, sourced from the now-closed Sleeping Beauty Mine in Arizona.
Tanzanite: A Modern Sensation
In stark contrast to Turquoise's ancient lineage, Tanzanite is a distinctly modern gemstone, discovered less than 60 years ago. Its story begins in the mid-20th century, and it was formally introduced to the world in 1968. The gemstone's name is a direct tribute to its exclusive geographic origin, as it is found in only one location on Earth: a small, remote region in Tanzania near the majestic Mount Kilimanjaro.
The credit for bringing Tanzanite to the global stage belongs to the renowned jewelry house Tiffany & Company, which recognized its extraordinary beauty and launched a major promotional campaign in 1968 to highlight its rarity. This strategic move successfully positioned Tanzanite as a premier blue gemstone, quickly earning it a place among the most popular colored stones of the 20th century. Its rapid rise to fame and its unique, limited-source origin have made it a symbol of exclusivity and modern luxury. As a testament to its significance, Tanzanite was also designated as the 24th-anniversary gemstone.
Zircon: The Ancient Sparkle
Zircon is another traditional December birthstone, possessing a brilliance and fire that rivals even diamond. Its history is complex, with its name's etymology tracing back to either the Arabic zarkun ("vermillion") or the Persian zargun ("gold-colored"). While blue zircon is the variety most associated with December, this mineral occurs in a rainbow of colors, including yellow, green, brown, red, and clear.
Zircon holds the distinguished title of the oldest known mineral on Earth. Samples of zircon found in Australia have been dated at an astonishing 4.4 billion years old, providing a tangible link to the earliest eons of our planet's history. In the Middle Ages, Zircon was believed to be a stone of wisdom, honor, and restful sleep, further cementing its role as a protective and beneficial gem.
Geological Formation and Sources
Understanding the genesis of these gemstones reveals the unique conditions required to create their distinct beauty.
Turquoise Formation and Sources
Turquoise is a secondary mineral that forms in arid regions where acidic, copper-rich water percolates through weathered volcanic or sedimentary rock. According to geological sources, the process begins when rainwater or melted snow passes through copper ore deposits known as copper porphyry. This water interacts with copper sulfides in the ore, creating an acidic solution. This copper-carrying acidic solution then reacts with aluminum and potassium present in the surrounding rocks, causing turquoise to precipitate and fill cavities.
The geographical sources of Turquoise are as varied as its colors. Historically, the most prized Persian turquoise originated from ancient mines in Iran. In the United States, significant deposits are found in the arid Southwest, with the Sleeping Beauty Mine in Arizona being a famous source of the pure, matrix-free blue variety.
Tanzanite Formation and Sources
Tanzanite's formation is a geological rarity, which directly explains its exclusivity. It is a variety of the mineral zoisite and is found in a single, small mining area in the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. The gemstone is formed through a unique geological process involving intense heat and pressure acting on the host rock. The fact that this specific set of geological conditions has occurred in only one place on Earth makes Tanzanite's supply inherently finite and contributes significantly to its value and allure.
Zircon Formation and Sources
Zircon is a mineral that crystallizes from magma in igneous rocks and is also found in metamorphic rocks. It is highly resistant to weathering and is often found in sedimentary deposits as well. As mentioned, the oldest known zircon crystals, dated at 4.4 billion years, come from Australia. While Australia is a significant source, zircon is also mined in other locations around the world, including Thailand, Cambodia, and Sri Lanka, particularly for the gem-quality blue varieties that are heat-treated to achieve their desirable color.
Gemological Properties
The scientific characteristics of these three gemstones define their durability, appearance, and value.
| Gemstone | Hardness (Mohs Scale) | Chemical Composition | Key Visual Properties |
|---|---|---|---|
| Turquoise | 5 - 6 | Copper Aluminum Phosphate | Opaque to semi-translucent; blue to green; often contains matrix (veining). |
| Tanzanite | 6 - 7 | Calcium Aluminum Hydroxyl Sorosilicate | Trichroic (shows blue, violet, and burgundy from different angles); typically heat-treated. |
| Zircon | 6.5 - 7.5 | Zirconium Silicate | High refractive index and dispersion (brilliance and fire); wide color range. |
Turquoise Properties
Turquoise is a relatively soft and porous gemstone, with a hardness of 5 to 6 on the Mohs scale. This makes it susceptible to scratching and breaking with moderate force. Its chemical composition is copper aluminum phosphate. A key characteristic of Turquoise is its opacity, meaning light does not pass through it. It ranges in color from sky blue to green, and its porous nature means it can be easily discolored by oils, cosmetics, and other chemicals. The presence of matrix—the remnant of the host rock—can add character but is generally less desirable in high-grade stones unless it forms a pleasing pattern.
Tanzanite Properties
Tanzanite has a hardness of 6 to 7 on the Mohs scale, making it moderately durable but more sensitive than harder gems. Its most famous and defining property is its pleochroism, specifically trichroism. This means that the stone displays three different colors—typically blue, violet, and a reddish-burgundy—when viewed from three different crystallographic directions. Most gem-quality tanzanite is heat treated to a stable blue-violet hue; this process is standard and accepted in the trade. It is also sensitive to sudden temperature changes, which can cause fracturing.
Zircon Properties
Zircon is one of the heaviest natural gemstones, and its high refractive index (approaching that of a diamond) gives it exceptional brilliance and "fire" (dispersion). With a hardness of 6.5 to 7.5, it is quite durable, though care must be taken with some varieties due to potential brittleness. While it occurs in many colors, the blue variety linked to December is often produced by heat-treating brown zircon. Its wide range of natural colors and its dazzling sparkle make it a versatile and underappreciated gemstone.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, these gemstones have been attributed with a range of symbolic meanings and powers.
- Turquoise is primarily associated with protection, health, and good fortune. Its lore is rich with tales of its ability to warn of danger and bring wealth.
- Tanzanite, as a modern discovery, has been linked to themes of transformation, spiritual awakening, and higher consciousness. Its unique discovery story and vibrant color are seen as symbols of individuality and modern elegance.
- Zircon has historically symbolized wisdom, honor, and restful sleep. Its brilliant sparkle is often associated with purity and clarity of thought.
Collectively, these three stones for December 16 are associated with themes of success, protection, and inner strength, making them deeply meaningful for the individuals who wear them.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones, and their varying properties dictate different handling procedures.
- Turquoise: Due to its porosity and softness, Turquoise requires gentle care. It should be cleaned only with warm, soapy water and a soft cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals. It is also important to protect turquoise from prolonged exposure to skin oils, lotions, and cosmetics, which can cause discoloration over time.
- Tanzanite: With a moderate hardness of 6-7, Tanzanite should be cleaned with warm, soapy water. It is crucial to avoid ultrasonic and steam cleaners, as the vibrations and high heat can damage the stone. It is also sensitive to sudden temperature changes, so it should not be subjected to rapid heating or cooling.
- Zircon: Zircon is generally safe to clean with warm, soapy water. However, some sources advise caution. It should be stored separately in a soft cloth or a compartmented jewelry box to prevent it from being scratched by other gems. It is recommended to avoid using harsh chemicals and ultrasonic cleaners. Some sources also caution against prolonged exposure to direct sunlight, which can potentially cause fading in certain colored zircons.
Conclusion
The birthstones for December 16—Tanzanite, Turquoise, and Zircon—represent a remarkable convergence of geological rarity, historical depth, and aesthetic diversity. Turquoise stands as the timeless guardian, an ancient stone of protection and good fortune cherished by civilizations for millennia. Tanzanite, the vibrant newcomer, captures the imagination with its exclusive origin and mesmerizing trichroic properties, embodying the spirit of modern discovery. Zircon, the ancient mineral with a billion-year-old legacy, offers unparalleled brilliance and a spectrum of colors, symbolizing wisdom and clarity.
For the individual born on this day, the choice among these three gemstones is a personal one. Each stone provides a unique connection to the natural world, a distinct historical narrative, and a specific set of symbolic meanings. Together, they form a powerful and beautiful triad, offering tokens of protection, success, and inner strength that are as enduring as the gems themselves.