For those born in the final month of the year, the question of a singular birthstone is met with a resplendent, multi-faceted answer. December is uniquely distinguished by four official gemstones: Tanzanite, Turquoise, Zircon, and Blue Topaz. This quartet offers a breathtaking spectrum of blue, from the sky-reflective hues of Topaz to the deep, violet-blue of Tanzanite and the historic, robin's-egg shade of Turquoise. This abundance provides a remarkable variety for personal expression, allowing individuals to select a stone that resonates with their style, story, and the specific meaning they wish to carry. While traditional birthstones for December were primarily Turquoise and Zircon, the modern list has expanded to include the relatively recent discovery of Tanzanite and the increasingly popular Blue Topaz. Each of these gems possesses a unique geological origin, a rich history, and distinct gemological properties, making the study of December's birthstones a fascinating journey through science, history, and lore.
The concept of birthstones themselves is an ancient tradition, believed to have originated with the Breastplate of Aaron, a ceremonial garment described in the Old Testament, which was set with twelve different gemstones representing the twelve tribes of Israel. Over time, these stones became associated with the twelve signs of the zodiac and, eventually, the twelve months of the year. The modern list of birthstones was standardized in 1912 by the National Association of Jewelers (now Jewelers of America) to create a consistent guide for the commercial jewelry trade. December's collection is a testament to the evolving nature of this tradition, incorporating both ancient talismans and modern marvels. This article will explore the history, geological formation, gemological properties, and symbolism of each of these four magnificent December birthstones, providing a comprehensive guide for gemstone enthusiasts, students, and anyone captivated by their wintry allure.
A Legacy of Blue: History and Lore
The December birthstones carry stories that span millennia and continents, reflecting humanity's enduring fascination with the color blue. Each stone has been woven into the cultural fabric of different civilizations, acquiring unique meanings and powers along the way.
Turquoise: The Ancient Talisman
Turquoise is arguably the most historically significant of the December stones, with a legacy stretching back thousands of years. Its name derives from the French phrase pierre tourques, or "Turkish stone," referencing the trade routes through which it was brought to Europe from Persia. Ancient civilizations revered this sky-blue stone. The Egyptians adorned themselves with Turquoise as early as 5500 BCE, believing it offered protection and symbolized rebirth. Pharaohs and priests wore intricate Turquoise jewelry, and the stone was often used to create elaborate funerary objects, including the famous burial mask of Tutankhamun, which was inlaid with Turquoise.
In Persian culture, Turquoise was considered a sacred stone of the heavens, believed to bring protection and good fortune. It was set into domes, swords, and jewelry as a ward against unnatural death and to ensure a safe journey. Native American cultures, particularly the Navajo, Zuni, and Pueblo peoples of the American Southwest, have a profound connection to Turquoise. For them, it is not merely a gemstone but a piece of the sky that has fallen to earth, a living entity that offers spiritual connection, healing, and protection. It remains a cornerstone of their artistry and spiritual life.
Zircon: The Diamond Imitator with Ancient Roots
Zircon is one of the oldest minerals on Earth, with zircon crystals found in Australia dating back over 4.4 billion years. Its history as a gemstone is equally long and storied. During the Middle Ages, Zircon was believed to promote honor, prosperity, and wisdom in its wearer. It was a popular stone for royalty and was often set into crowns and scepters. A common belief was that Zircon could induce sleep, ward off evil spirits, and protect travelers from injury and disease.
In the 19th century, as diamond's popularity surged, colorless Zircon became one of its most convincing imitations due to its high refractive index and strong dispersion (fire). This led to it being called "Matura Diamond." While it has often been overshadowed by diamond in the modern era, Zircon's own merits as a brilliant and durable gem, with a history spanning centuries, secure its place as a cherished birthstone.
Tanzanite: The Modern Marvel
Tanzanite is the newest member of the December family, discovered by Maasai herders in the Merelani Hills of Tanzania in 1967. Its discovery is a relatively recent event in the gemological world, and its story is one of modern exploration and commercialization. Shortly after its discovery, the Tiffany & Co. jewelry house recognized its extraordinary beauty and launched a major marketing campaign in 1968, dubbing it the "gem of a generation" and presenting it as a more accessible alternative to sapphire. Its unique, saturated violet-blue color, which is pleochroic (showing different colors from different angles), quickly captivated the market. Tanzanite's status as a birthstone was solidified when it was added to the modern birthstone list in 2002, making it a symbol of new beginnings and contemporary elegance.
Blue Topaz: The Popular Modern Alternative
Topaz itself has a long history, but the vibrant blue variety that has become a December birthstone is largely a product of modern gemology. Naturally occurring blue Topaz is exceedingly rare; the vast majority of blue Topaz on the market is created through the irradiation and heat treatment of colorless Topaz. This process makes the stone widely available and affordable, contributing to its immense popularity. While its use as a formal birthstone is more recent, Topaz has been valued for centuries for its wide range of colors and its impressive size and clarity. The association with the color blue and its durability have made it a favored choice for contemporary jewelry, earning it a place on the modern list of December stones.
Geological Formation and Mining Locations
The four December birthstones originate from vastly different geological environments, which accounts for their unique characteristics and availability.
Turquoise
Turquoise is a secondary mineral that forms when water containing copper, aluminum, and other minerals seeps through pre-existing rock, typically in arid or semi-arid regions. This process occurs near the surface, filling cavities and fractures in rocks like limestone or sandstone. The presence of copper is responsible for the stone's characteristic blue color, while iron impurities can shift it toward green.
The most significant sources of Turquoise are in the United States, particularly in Arizona (e.g., the Sleeping Beauty, Kingman, and Bisbee mines), Nevada, and New Mexico. Other notable sources include Iran (historically the source of the finest "Persian Turquoise"), China, and Egypt.
Zircon
Zircon is a zirconium silicate mineral that crystallizes from magma as an accessory mineral in igneous rocks like granite and syenite. It is extremely durable and resistant to weathering, which is why ancient zircon crystals can be found in sedimentary deposits known as placer deposits, where they have been eroded from their original host rock and concentrated by water action.
Major sources of gem-quality Zircon include Cambodia (for the highly prized "Mekong Diamond" blue zircon), Sri Lanka, Thailand, Australia, and Vietnam.
Tanzanite
Tanzanite is a variety of the mineral zoisite and is found in only one location in the world: the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. Its formation is unique, believed to have occurred approximately 585 million years ago during a massive tectonic plate shift and mountain-building event. The intense heat from this event caused the original zoisite crystals to be chemically altered and infused with vanadium, which gives Tanzanite its signature blue-violet hue. The limited geographic area of its occurrence makes it significantly rarer than diamond.
Blue Topaz
Topaz forms in igneous rocks like granite and rhyolite, often in large, prismatic crystals within gas pockets in cooling magma. It can also be found in metamorphic rocks.
While Topaz occurs in many locations globally, including Brazil, Pakistan, and Russia, the sources for the colorless Topaz that is subsequently treated to become blue Topaz are primarily in Brazil. The United States is also a source of Topaz, with Texas even naming it its state gem.
Gemological Properties
Understanding the physical and chemical properties of these gemstones is crucial for gemologists, jewelers, and consumers alike. These properties determine a stone's durability, appearance, and care requirements.
| Gemstone | Mineral Species | Chemical Formula | Mohs Hardness | Crystal System | Key Properties |
|---|---|---|---|---|---|
| Turquoise | Turquoise | CuAl₆(PO₄)₄(OH)₈·4H₂O | 5 - 6 | Triclinic | Often contains a matrix (web-like inclusions); opaque to translucent; can be dyed or stabilized. |
| Zircon | Zircon | ZrSiO₄ | 6.5 - 7.5 | Tetragonal | High refractive index and dispersion ("fire"); can be heat-treated to produce colorless or blue stones. |
| Tanzanite | Zoisite | Ca₂Al₃(SiO₄)₃(OH) | 6.5 - 7 | Orthorhombic | Strong pleochroism (blue, violet, burgundy); often heat-treated to enhance color; relatively included. |
| Blue Topaz | Topaz | Al₂SiO₄(F,OH)₂ | 8 | Orthorhombic | Excellent clarity; typically colorless before treatment; irradiation and heat create blue color. |
Turquoise
With a Mohs hardness of 5 to 6, Turquoise is relatively soft compared to other gemstones. This makes it susceptible to scratching and requires careful handling. It is also porous, which means it can absorb oils, chemicals, and lotions, potentially altering its color over time. Most Turquoise on the market today is stabilized—treated with a resin or wax to harden it and prevent color change—or dyed to enhance its color. The presence of a "matrix," the host rock material that remains within the turquoise, is a common feature and can create beautiful, intricate patterns.
Zircon
Zircon has a Mohs hardness of 6.5 to 7.5, making it a reasonably durable stone suitable for all types of jewelry, though it can be brittle due to its tetragonal crystal structure. It possesses a very high refractive index (1.92-1.98), which is higher than that of a diamond, giving it exceptional brilliance. Its strong dispersion (0.039) gives it a "fire" that rivals diamond, producing flashes of rainbow color. Most blue Zircon is created by heating brown Zircon crystals to a high temperature in a controlled environment, a process that removes the brown color and produces a desirable blue hue.
Tanzanite
Tanzanite has a Mohs hardness of 6.5 to 7, making it moderately durable, but it can be brittle due to its cleavage properties (the tendency to break along flat planes). This is a critical consideration for jewelers when setting the stone. Its most famous characteristic is its strong pleochroism. When viewed from different angles, it can display three distinct colors: blue, violet, and a reddish-burgundy. Most gemstones are cut to display the desirable blue-violet face-up color, while the reddish component is seen from the side. Nearly all commercial Tanzanite is heat-treated to remove the brownish tones and produce the pure blue-violet color for which it is known.
Blue Topaz
Blue Topaz is one of the most durable of the December stones, with a Mohs hardness of 8. This makes it an excellent choice for jewelry that is worn daily, such as rings and bracelets. It is also typically very "clean," meaning it has few internal inclusions, resulting in a bright, transparent appearance. The blue color is not natural; it is achieved through irradiation of colorless Topaz, followed by heat treatment. The depth of the blue can be controlled by the intensity of the treatment, resulting in shades like Sky Blue, Swiss Blue, and the deep, saturated London Blue.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, the December birthstones are rich in symbolism and are believed by many to possess metaphysical properties.
- Turquoise is widely regarded as a stone of protection, healing, and good fortune. It is believed to act as a shield against negative energy, promote inner calm, and aid in honest communication. It is also associated with grounding and spiritual attunement.
- Tanzanite is seen as a stone of transformation and new beginnings. Its discovery in modern times lends it an energy of progress and spiritual awakening. It is believed to enhance intuition, promote a higher consciousness, and help individuals move forward with clarity and purpose.
- Zircon is associated with clarity, wisdom, and balance. It is believed to help focus the mind, reduce negativity, and attract prosperity and honor. Some also consider it a stone of spiritual grounding and protection during travel.
- Blue Topaz symbolizes calmness, love, and clarity. Its serene blue hue is thought to promote relaxation, soothe frayed nerves, and encourage clear, compassionate communication. It is often given as a token of affection and fidelity.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of December birthstone jewelry. Due to their varying hardness and stability, each stone requires a slightly different approach.
- Turquoise: Clean with warm water, a mild soap, and a soft cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals, which can damage the stone or strip any stabilizing treatments. Store it separately to avoid scratches.
- Zircon: While relatively hard, Zircon can be brittle. Clean with warm soapy water and a soft brush. Avoid sudden temperature changes and ultrasonic cleaners, as these can cause fractures in some stones.
- Tanzanite: Due to its cleavage and moderate hardness, Tanzanite requires gentle care. Clean with warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaners. It is best to remove Tanzanite jewelry before activities that could cause impact.
- Blue Topaz: As the most durable of the group, Blue Topaz can be cleaned with warm soapy water, an ultrasonic cleaner, and even a steam cleaner. However, it is still susceptible to scratches, so it should be stored carefully. Avoid sudden, extreme temperature changes.
Conclusion
The birthstones of December—Tanzanite, Turquoise, Zircon, and Blue Topaz—offer a captivating journey through geological time, human history, and personal meaning. From the ancient, protective talisman of Turquoise to the brilliant, diamond-like fire of Zircon, the modern, transformative allure of Tanzanite, and the serene, durable beauty of Blue Topaz, this quartet provides an unparalleled selection for those born in the year's final month. Their shared palette of blue reflects the month's icy skies and deep twilight, yet each stone tells its own unique story. Whether chosen for its historical significance, its metaphysical properties, or simply its breathtaking color, a December birthstone is more than just a piece of jewelry; it is a personal emblem of identity, a connection to the natural world, and a timeless treasure.