The final month of the Gregorian calendar is uniquely endowed with a trio of birthstones, each a distinct expression of the color blue. For individuals born on December 22nd, the designated gems are Tanzanite, Turquoise, and Zircon. This selection is not arbitrary; it reflects a confluence of historical precedence, geological rarity, and a shared chromatic theme that evokes the deep hues of winter skies and tranquil waters. While many months are assigned a single gem, December offers a spectrum of choice, allowing for personal expression through stones that range from the opaque, ancient charm of Turquoise to the vivid, violet-blue of Tanzanite and the brilliant fire of Zircon.
These three gemstones, though visually distinct, are united by their cultural significance and their journey through human history. Turquoise is one of the oldest known gemstones, cherished by civilizations spanning from ancient Egypt to the pre-Columbian Americas. Tanzanite represents a modern marvel, a recent discovery that rapidly achieved global fame for its unparalleled color. Zircon, often confused with the synthetic cubic zirconia, is one of the oldest minerals on Earth, with a history of use in jewelry that stretches back centuries. This article will explore the geological origins, gemological properties, historical lore, and practical care of these three remarkable stones, providing a comprehensive guide to the birthstones of December 22nd.
History and Lore: A Journey Through Time
The historical narratives of Tanzanite, Turquoise, and Zircon are as varied as their appearances, each stone carrying a legacy shaped by the cultures that prized it.
Turquoise: The Ancient Talisman
Turquoise stands as the traditional birthstone for December, with a history of human use dating back over millennia. Its name provides a clue to its long and winding path into global consciousness. The word "Turquoise" is derived from the French phrase pierre turquoise, meaning "stone of Turkey." This name was bestowed upon the gem when it was brought to Europe from Turkish bazaars, though its origins lie far from the Ottoman Empire. This ancient, semi-translucent to opaque gem has been a source of fascination for numerous great civilizations.
The pharaohs and elite of ancient Egypt adorned themselves with Turquoise, valuing its striking blue-green color. Chinese artisans were carving the stone more than 3,000 years ago, demonstrating its early importance in Eastern cultures. In Persian and Native American traditions, Turquoise was not merely an ornament but a powerful protective talisman. It was widely believed to possess beneficial powers, capable of guaranteeing health, good fortune, and success. From the 13th century onward, a popular European belief held that Turquoise could protect the wearer from falls, particularly from horses, and that the stone would shatter upon the approach of disaster, thereby absorbing the harm intended for its owner. Hindu mystics believed that gazing upon a Turquoise after first seeing the new moon would bring immense wealth. The Apache people held a more mystical belief, suggesting that Turquoise could be found by following a rainbow to its end. This rich tapestry of beliefs cemented Turquoise’s status as a stone of protection, luck, and prosperity.
Tanzanite: The Modern Marvel
In stark contrast to Turquoise’s ancient origins, Tanzanite is a distinctly modern addition to the world of gemstones. Discovered in the 1960s in the Merelani foothills of Mount Kilimanjaro in Tanzania, this gemstone is, in geological terms, a relative newcomer. Its rapid ascent to prominence is a testament to its extraordinary beauty. Tanzanite is prized for its vivid, saturated blue to violet hues, a color range unique among other blue gemstones.
The gem is a variety of the mineral zoisite and owes its captivating color to heat treatment, a standard industry practice that transforms naturally occurring brownish zoisite into the desirable blue-violet gem. Its limited geographical source—found only in a small, specific area of Tanzania—contributes to its rarity and value. Despite its short history, Tanzanite has already become imbued with symbolic meaning, often associated with transformation, new beginnings, and a sense of spiritual awakening, reflecting its dramatic and vibrant appearance.
Zircon: The Stone of Clarity and Misunderstanding
Zircon, the third member of December’s birthstone trio, has a history that is both ancient and fraught with confusion. As one of the oldest minerals on Earth, Zircon has been known since antiquity. Its exceptional brilliance and high refractive index, which gives it a fiery sparkle rivaling that of diamond, made it a popular gem in jewelry. However, its similarity in name and appearance to other stones has led to significant misunderstanding.
Historically, Zircon was frequently mistaken for other gemstones, including diamond and, more recently, the synthetic cubic zirconia (CZ). This confusion has unfortunately overshadowed Zircon’s own merits. In its blue variety, Zircon has been cherished for centuries. It is associated with wisdom, clarity, and balance. The stone is believed to promote mental and emotional equilibrium, helping its wearer to see things with greater clarity and understanding. This association with wisdom, combined with its brilliant sparkle, makes blue Zircon a compelling and meaningful birthstone.
Geological Formation and Sources
Understanding the origins of these gemstones reveals the unique geological processes that create their distinct forms and colors.
Turquoise: A Product of Water and Minerals
Turquoise is a secondary mineral that forms when water containing copper and aluminum seeps through pre-existing rock. This process, known as percolation, occurs in arid regions where the water table can interact with these minerals. Over long periods, the water evaporates, leaving behind deposits of turquoise in the host rock. The presence of copper is responsible for the stone’s characteristic blue color, while iron and chromium can shift the hue toward green.
The color and texture of Turquoise are heavily influenced by its host rock. The dark veins and web-like patterns visible in many turquoise specimens are known as matrix. This matrix is actually remnants of the surrounding rock in which the turquoise formed, making each piece uniquely patterned. Major sources of Turquoise include Iran (historically the source of the finest "Persian turquoise"), the Southwestern United States (Arizona, New Mexico, Nevada), China, and Egypt.
Tanzanite: A Singular Geological Anomaly
Tanzanite’s existence is the result of a unique and specific geological event. It is a variety of the mineral zoisite that was subjected to intense heat and pressure from the tectonic plate movement that created the East African Rift Valley and Mount Kilimanjaro. This process, which occurred approximately 585 million years ago, altered the brownish zoisite, introducing vanadium which resulted in its signature blue-violet color.
The geological conditions required for this transformation were incredibly rare, confining the gemstone to a single, small mining area near Mount Kilimanjaro. This extreme rarity is a key factor in its value. Miners extract Tanzanite from alluvial deposits, where water has transported and concentrated the crystals from their original host rock.
Zircon: A Primary Mineral from Magma
Unlike Turquoise and Tanzanite, Zircon is a primary mineral, meaning it crystallizes directly from molten magma as it cools. It is one of the first minerals to form in cooling magmatic rock, a process that can take place over millions of years. This durable mineral can survive through geological cycles, including erosion and sedimentation, which is why it is often found in riverbeds and sedimentary deposits (alluvial deposits).
Zircon deposits are found in a variety of locations worldwide, including Australia, Sri Lanka, Thailand, Cambodia, and the United States. The blue color in blue Zircon is typically achieved through heat treatment of brown zircon crystals, a process that has been refined over many years.
Gemological Properties
The three December birthstones differ significantly in their physical and chemical properties, which in turn affects their durability, appearance, and value. The following table summarizes their key characteristics based on available information.
| Property | Tanzanite | Turquoise | Zircon |
|---|---|---|---|
| Mineral Family | Zoisite (a member of the epidote group) | A secondary phosphate mineral | Zirconium Silicate |
| Chemical Formula | Ca₂Al₃(SiO₄)₃(OH) | Hydrated copper and aluminum phosphate | ZrSiO₄ |
| Crystal System | Orthorhombic | Triclinic | Tetragonal |
| Hardness (Mohs) | 6.5 - 7 | 5 - 6 (can vary with porosity) | 7.5 |
| Refractive Index | 1.690 - 1.700 | 1.610 - 1.650 | 1.92 - 2.01 |
| Luster | Vitreous (glass-like) | Waxy to subvitreous | Adamantine (brilliant) |
| Transparency | Transparent to translucent | Opaque to semi-translucent | Transparent to translucent |
| Notable Features | Strong trichroism (displays three different colors: blue, violet, and red-brown); almost always heat-treated. | Often contains a "matrix" (web-like inclusions of host rock); color can be altered by chemicals, sweat, or cosmetics. | Exceptionally high refractive index and brilliance; often treated with heat to achieve blue color. |
Color, Clarity, Cut, and Carat
Turquoise: Its value is primarily determined by its color and texture. The most prized color is an even, intense "robin's egg" blue, free from greenish undertones. Specimens with a minimal or non-existent matrix are generally more valuable. As it is typically opaque, clarity is not a grading factor in the same way as for transparent gems. It is often cut into cabochons, beads, and carvings.
Tanzanite: The most sought-after color is a deep, vibrant blue with a distinct violet undertone. The strongest and most saturated colors are found in larger stones. Due to its strong trichroism, cutters must orient the crystal carefully to display the desired blue-violet face-up color. Clarity is important, with cleaner stones commanding higher prices. It is most often faceted for use in rings, earrings, and pendants.
Zircon: The ideal blue Zircon has a rich, vivid blue color, often with a hint of green. Its most defining feature is its exceptional brilliance and "fire," which rivals that of diamond. This is due to its high refractive index and strong dispersion. Clean, well-cut Zircons are highly prized. It is faceted into brilliant cuts to maximize its sparkle and is available in a wide range of sizes.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, these three stones have been attributed with a range of powerful metaphysical properties.
- Turquoise is overwhelmingly seen as a stone of protection, healing, and good fortune. It is believed to act as a spiritual shield, warding off negative energy and harm. Many also associate it with emotional balance, stress relief, and the fostering of creative expression and self-awareness.
- Tanzanite, as a modern gem, has developed symbolic meanings that reflect its unique character. It is considered a stone of transformation, spiritual awakening, and higher consciousness. Its intense color is believed to stimulate the throat and third-eye chakras, promoting clear communication and intuitive insight. It is also associated with a sense of calm and serenity.
- Zircon is primarily linked to wisdom, clarity, and mental balance. It is thought to help its wearer think more clearly and make decisions with greater confidence. The stone is also believed to promote spiritual grounding and to ward off nightmares, ensuring peaceful sleep. Its brilliant light is a metaphor for illuminating the path forward.
Care and Cleaning
Proper care is essential to maintain the beauty of these gemstones, and their differing hardness and stability require specific handling.
Turquoise (Hardness 5-6): As the softest and most porous of the three, Turquoise requires gentle care. It is susceptible to scratching and can be damaged by chemicals, including perfumes, lotions, and even the oils and acids in skin sweat, which can cause discoloration over time. To clean it, use only a soft, dry cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh soaps. It is best to put on turquoise jewelry after applying cosmetics.
Tanzanite (Hardness 6.5-7): While harder than Turquoise, Tanzanite is still considered fragile due to its perfect cleavage in one direction, meaning it can split if struck with force. It is not ideal for rings or bracelets that are worn daily, where impact is more likely. To clean, use warm water, a mild soap, and a soft brush. As with Turquoise, avoid ultrasonic and steam cleaners.
Zircon (Hardness 7.5): Zircon is the most durable of the three birthstones, making it a more suitable choice for everyday jewelry. However, it can still be scratched by stones with higher hardness, such as sapphire or diamond. It is also somewhat brittle and can be chipped by a sharp blow. Cleaning is straightforward: use warm soapy water and a soft brush. While generally stable, some zircon may be sensitive to strong light and heat, but this is rarely an issue with normal wear.
Conclusion
The birthstones for December 22nd—Tanzanite, Turquoise, and Zircon—offer a remarkable study in diversity. They span the spectrum from an ancient, earthy talisman of protection to a modern, vibrant symbol of transformation, and a brilliant, fiery gem of wisdom. Each stone possesses a unique geological story, a distinct set of physical properties, and a rich history of human belief and appreciation. For those born on this day, the choice between the opaque charm of Turquoise, the vivid color of Tanzanite, and the sparkling fire of Zircon provides a personal connection to a legacy of beauty and meaning. Together, this triad of blue gems perfectly captures the serene and profound essence of the year’s final month.