December is unique in the world of birthstones, offering not one, but a quartet of captivating blue gems. While most months are assigned a single stone, December’s traditional and modern birthstones provide a rich variety of color, history, and symbolism. The primary December birthstone is turquoise, a gem cherished for millennia for its distinctive sky-blue hue. It is joined by zircon and tanzanite, with blue topaz frequently appearing in modern lists. This abundance of choice reflects a cool, wintry palette that mirrors December’s icy skies and deep twilight blues. Each stone possesses its own distinct personality, geological origin, and cultural lore, from ancient amulets of protection to modern symbols of transformation and clarity.
This article delves into the history, properties, and significance of each of December’s four birthstones. We will explore their geological formation and sources, examine their gemological characteristics, uncover the metaphysical beliefs surrounding them, and provide guidance on their care. For enthusiasts, collectors, and those born in December, understanding these gems offers a deeper appreciation for the treasures of this winter month.
History and Lore
The journey of December’s birthstones is a tapestry woven through ancient civilizations, royal courts, and modern gem trade associations.
Turquoise stands as the oldest and most storied of the group. Its name derives from the French pierre turquoise, meaning "Turkish stone," as it was brought to Europe through Turkish gem markets. The stone’s history, however, predates this trade by millennia. Turquoise has been prized since ancient Egypt over 3,000 years ago. It was a favored gem for amulets, prized for its relative ease of carving and inscribing. Ancient cultures believed it offered protection against danger and could warn its wearer of approaching illness by becoming pale. This protective quality was universal; from the Egyptians to the Tibetans, who used it as currency, and the Incas and Mayas, who offered it to gods, turquoise was synonymous with good fortune and health. In the American Southwest, Native American tribes associated it with youth and strength. For royalty, it was a symbol of wisdom and tranquility, famously adorning the burial mask of King Tutankhamun.
The other stones have more recent, yet equally compelling, histories. Zircon is one of the oldest known minerals on Earth, with zircon crystals found in Australia dating back over 4.4 billion years. While naturally occurring in a spectrum of colors, the blue variety has become a prominent December birthstone. Historically, zircon was confused with more expensive gems like diamond, and its brilliant sparkle made it a popular diamond simulant. It is associated with wisdom, prosperity, and good fortune, believed to sharpen focus and boost mental clarity.
Tanzanite is the youngest of the traditional trio, a modern discovery that captured the gemological world. It was first identified in the 1960s in the Merelani Hills of Tanzania. Its rapid rise to birthstone status was orchestrated by Tiffany & Co., which launched a major marketing campaign in 1968, touting it as "the most beautiful blue gemstone discovered in 2,000 years." Recognizing its unique appeal, the American Gem Trade Association (AGTA) officially added tanzanite to the birthstone list in 2002, giving December a gem that represents transformation, intuition, and spiritual growth.
Blue topaz, while not a traditional birthstone for December, has gained significant popularity in modern times. Its inclusion in some lists, such as those from the American Gem Society, stems from its availability in a wide range of captivating blue shades—from sky blue to deep London blue—and its exceptional durability. It symbolizes clarity, communication, and calmness, making it a favored choice for contemporary jewelry.
The expansion of December’s birthstone list is a deliberate choice to offer consumers more flexibility in price, durability, and style. Unlike the standardized lists of the past, today’s December celebrants can choose a stone that best reflects their personality, from the ancient and protective turquoise to the modern and transformative tanzanite.
Geological Formation and Sources
The formation and mining locations of these gems are as diverse as their histories, spanning continents and geological environments.
Turquoise forms in arid regions where acidic water, rich in copper, seeps through porous rock and reacts with minerals containing aluminum and phosphorus. This process, taking millions of years, creates veins and nodules of the mineral chalcedony. The most significant sources are in the Southwestern United States (Arizona, New Mexico, Nevada, and Colorado), Iran (historically the source of the finest “Persian” turquoise), Egypt, China, Mexico, and parts of Central Asia and Africa. The gem’s characteristic matrix—the host rock embedded in the stone—varies by location, creating unique patterns like the prized spiderweb matrix found in some American and Persian specimens.
Zircon is a zirconium silicate that forms in igneous and metamorphic rocks. The blue variety is typically created through heat treatment of brownish zircon crystals, which are mined in countries like Sri Lanka, Cambodia, Myanmar, and Australia. Australia is the world’s leading producer of zircon, though much of it is used for industrial purposes. The gem-quality blue zircon used in jewelry often originates from Southeast Asia.
Tanzanite is found in only one location in the world: the Merelani Hills of Tanzania, near the base of Mount Kilimanjaro. Its formation is linked to a unique geological event—the heating and metamorphism of host rocks by a massive intrusion of magma. This process created the conditions for the formation of zoisite, the mineral family to which tanzanite belongs. The gem is mined from four distinct zones in the Merelani area, with Zone 1 being the most productive. Due to its single-source origin, tanzanite is considered one of the rarest gemstones.
Blue topaz is a variety of the mineral topaz, which forms in igneous rocks like granite and rhyolite. Natural blue topaz is exceptionally rare; the vibrant blue hues seen in the market are almost always the result of irradiation and heat treatment of colorless or pale topaz crystals. Major sources of the base material include Brazil, Nigeria, and Sri Lanka, with the treatment process often occurring in the United States. The specific shades—Sky Blue, Swiss Blue, and London Blue—are achieved through controlled treatment to meet market demand.
Gemological Properties
Understanding the physical and optical properties of these gems is essential for both appreciation and care. The following table summarizes key characteristics, based on data from gemological sources.
| Gemstone | Color & Varieties | Mohs Hardness | Chemical Composition | Key Properties |
|---|---|---|---|---|
| Turquoise | Blue to green, often opaque with a matrix | 5 – 6 | Hydrated copper aluminum phosphate | Porous, can be dyed or stabilized; color can fade with prolonged sun exposure. |
| Tanzanite | Violet-blue to deep blue, strongly pleochroic | 6 – 7 | Calcium aluminum hydroxyl silicate (Zoisite) | Shows blue, violet, and reddish hues from different angles; sensitive to heat and sudden temperature changes. |
| Blue Topaz | Sky Blue, Swiss Blue, London Blue | 8 | Aluminum silicate fluoride hydroxide | Very hard and durable, ideal for daily wear; color is typically treated. |
| Zircon | Brilliant blue (also colorless, yellow, green) | 6.5 – 7.5 | Zirconium silicate | High refractive index and dispersion (fire); can be brittle and prone to chipping. |
Turquoise is relatively soft, with a hardness of 5 to 6 on the Mohs scale, making it susceptible to scratching and abrasion. Its porous nature means it can absorb oils, lotions, and chemicals, which may alter its color. Many commercial turquoise stones are stabilized with resin or wax to improve durability and color consistency.
Tanzanite has a hardness of 6 to 7, but it has perfect cleavage in one direction, making it vulnerable to breaking if struck with force. Its most famous characteristic is pleochroism—it displays three distinct colors (blue, violet, and red/brown) depending on the crystal orientation. This property is harnessed during cutting to showcase the most desirable blue-violet hue.
Blue topaz is one of the hardest and most durable of the group, with a Mohs hardness of 8. It is resistant to scratching and breaking, making it an excellent choice for rings and bracelets that endure daily wear. Its color is stable and will not fade under normal lighting conditions.
Zircon has a high refractive index, giving it exceptional brilliance and fire, often surpassing that of diamond. While its hardness (6.5–7.5) is respectable, it is brittle and can be prone to chipping, especially in thin settings. Cutters must handle it with care to preserve its edges.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, these gems have been imbued with symbolic meanings and metaphysical powers.
Turquoise is the quintessential stone of protection. Ancient warriors wore it into battle, and travelers carried it for safe passage. It is believed to ward off negative energy, promote healing, and bring good fortune. In relationships, it is said to foster friendship and loyalty, making it a popular gift. Its calming blue-green color is associated with tranquility, wisdom, and emotional balance.
Tanzanite, as a modern gem, carries symbolism of transformation and spiritual awakening. Its striking color is linked to intuition, higher consciousness, and the ability to see beyond the mundane. It is often associated with new beginnings and personal growth, making it a meaningful stone for those navigating significant life changes.
Zircon is traditionally associated with wisdom, prosperity, and good fortune. It is believed to sharpen mental clarity, enhance focus, and attract success. In some traditions, it is also linked to purity and honor. Its brilliant sparkle is thought to inspire creativity and joy.
Blue topaz embodies qualities of clear communication, calmness, and emotional balance. It is often associated with truth and forgiveness, helping to articulate thoughts and feelings with clarity. Its soothing blue hue is believed to reduce stress and promote a sense of peace and tranquility.
Care and Cleaning
Proper care is crucial to maintain the beauty and longevity of each December birthstone, given their varying physical properties.
Turquoise requires the most diligent care. It should be cleaned with a soft, dry cloth. Avoid exposing it to chemicals, including household cleaners, cosmetics, and even lotions, as they can damage its surface. Do not use ultrasonic or steam cleaners. Store turquoise jewelry separately to prevent scratching, and keep it away from prolonged direct sunlight, which can cause fading.
Tanzanite is moderately durable but requires careful handling. It is sensitive to heat and rapid temperature changes, so it should never be exposed to high heat or placed near a hot surface. Cleaning can be done with warm, soapy water and a soft brush. Avoid ultrasonic cleaners, as the vibrations can cause internal fractures. Due to its perfect cleavage, it is best set in protective settings like bezels or pendants for everyday wear.
Blue topaz is the most durable of the four and is relatively easy to care for. It can be safely cleaned with warm, soapy water and a soft brush. It is generally safe for ultrasonic cleaners, though it’s best to check with a jeweler if the stone is set in a delicate or antique piece. Its hardness makes it resistant to most everyday hazards, but it should still be stored separately from other jewelry to prevent scratching.
Zircon is brittle and should be handled with care to avoid knocks and impacts. It can be cleaned with warm, soapy water and a soft brush. Avoid ultrasonic cleaners, as the vibrations may cause the stone to fracture. Store zircon jewelry in a padded compartment or soft cloth to protect it from damage.
Conclusion
December’s birthstones offer a remarkable spectrum of choices, from the ancient and protective turquoise to the modern and transformative tanzanite, the brilliant and wise zircon, and the durable and serene blue topaz. Each gem carries a unique story, from the arid copper-rich deserts where turquoise forms to the singular volcanic hills of Tanzania where tanzanite is found. Their gemological properties, from the soft, porous nature of turquoise to the exceptional hardness of blue topaz, dictate both their use in jewelry and the care they require. Symbolically, they encompass a range of human aspirations: protection, transformation, wisdom, and clarity. For those born in December, this quartet of blue gems provides not just a birthstone, but a palette of meaning, history, and beauty to choose from, ensuring a personal and enduring connection to the month’s icy splendor.