The final month of the year is uniquely distinguished in the world of gemology by its abundance of birthstones. While most months are assigned a single gem, December is celebrated with four distinct options: Blue Topaz, Blue Zircon, Tanzanite, and Turquoise. This variety offers a spectrum of icy blues, from the soft sky tones of turquoise to the deep, vivid hues of tanzanite and London Blue topaz. The tradition of multiple stones for a single month evolved from a need to provide consumers with more choices in terms of color, availability, and price. Each of these gems carries its own rich history, unique geological origins, and specific set of properties, creating a diverse and fascinating collection for those born in the chill of winter.
This article will delve into the individual characteristics of each of December's four primary birthstones. We will explore the historical significance and lore associated with these gems, from ancient amulets to modern symbols of transformation. An examination of their geological formation and primary sources will reveal the specific conditions required to create these beautiful minerals. Furthermore, a detailed analysis of their gemological properties—including hardness, chemical composition, and optical characteristics—will provide the scientific foundation for understanding their value and durability. Finally, practical guidance on the care and cleaning of each stone will be offered, ensuring that these December gems can be properly maintained and appreciated for generations.
History and Lore
The history of December's birthstones spans millennia and continents, with each gem holding a special place in different cultures. Turquoise is arguably the most ancient of the group, with a lineage of use that stretches back thousands of years. Its name itself tells a story of trade and travel; it was known as turkis or turkeystone because it was sourced from Persia and the Sinai Peninsula and made its way to European markets through Constantinople, Turkey. This relative ease of cutting and inscribing made it a favored material for amulets from the earliest times. Beliefs surrounding its protective powers were widespread. It was thought to safeguard the wearer from danger and bring good fortune. In relationships, turquoise was prized by lovers and married couples as a stone that could protect their bond, and it was believed that a gift of turquoise would preserve friendship. Some traditions held that the stone could act as a warning system, becoming pale to signal an approaching illness or danger. The Tibetans held turquoise in particularly high regard, viewing it as a birthstone of fortune, health, and success, and even using it as a form of currency. For the ancient Incas and Mayas, it was a precious offering to their gods, while for the Native American peoples of the Southwest, it was a gemstone symbolizing youth and strength.
While turquoise boasts an ancient heritage, Tanzanite is a product of the modern era, a recent addition to the gemological world. Its discovery is a 20th-century story, adding a contemporary chapter to December's gemstone legacy. Although its history is short, its symbolism is powerful. Tanzanite is strongly linked to themes of transformation, growth, and new beginnings. Its captivating blue-violet color is said to reflect the feeling of stepping into a new chapter of life with clarity and curiosity. This association with major life shifts makes it a popular choice for commemorative jewelry.
Zircon, another of December’s gems, carries a history of being mistaken for a much more famous stone. It is a gem with incredible sparkle, so much so that it is often confused with diamond. Its association with clarity, wisdom, and balance has made it a meaningful stone throughout history. The word "topaz" itself is believed to derive from the Sanskrit word "tapas," meaning fire. Historically, topaz in its various forms was linked to strength and protection. In its modern blue incarnation, Blue Topaz has come to represent love and fidelity, making it a popular choice for romantic gifts and a symbol of enduring affection.
Geological Formation and Sources
The origins of these four gems are as varied as their histories. Each was formed under unique geological conditions and is mined from specific regions around the globe.
Turquoise is a hydrous phosphate of copper and aluminum. It is not a crystalline mineral but rather a cryptocrystalline aggregate, formed in arid regions where acidic, copper-rich groundwater seeps down and reacts with aluminum-bearing minerals in the rock. This slow process can take millions of years, creating the nodules and veins that are mined for gemstones. Historically, the primary sources were Persia (modern-day Iran) and the Sinai Peninsula. While these regions still produce highly valued material, significant turquoise deposits are also found in the Southwestern United States, particularly in Arizona, New Mexico, and Nevada, as well as in Chile, China, and Tibet.
Tanzanite is a variety of the mineral zoisite and owes its existence to a rare geological event. It is found in only one place on Earth: the Merelani Hills of Northern Tanzania, near the base of Mount Kilimanjaro. Its formation is believed to be the result of a unique combination of intense heat and pressure from a tectonic event that occurred roughly 585 million years ago, which altered the host rock and infused it with the elements needed to create this vibrant blue gem. Due to its extremely limited geographic source, it is considered one of the rarest gemstones in the world.
Zircon is a mineral composed of zirconium silicate. It is one of the oldest minerals on Earth, with crystals found in Australia that are over 4.4 billion years old. It forms in igneous and metamorphic rocks and is found as a common accessory mineral in many rock types. However, gem-quality zircon is much rarer. Major sources include Cambodia, Sri Lanka, and Thailand, with significant deposits also found in Australia, Myanmar, and East Africa. It is important to distinguish gem zircon from the synthetic material zirconia (cubic zirconia), which is a diamond simulant.
Blue Topaz is a silicate mineral of aluminum and fluorine. Naturally occurring blue topaz is exceptionally rare. Most of the vibrant blue topaz seen in the jewelry market today is the result of a process where colorless or pale topaz, which is more readily available, is irradiated and then heat-treated to induce a deep blue color. The United States is a notable source for topaz, with the state of Texas even declaring Blue Topaz its official state gem. Other sources include Utah and California.
Gemological Properties
Understanding the physical and chemical properties of a gemstone is crucial for identifying it, assessing its quality, and knowing how to care for it. The four December stones differ significantly in these characteristics.
Turquoise is valued for its distinctive robin's-egg blue to greenish-blue color, often marked by a characteristic "spiderweb" matrix of the host rock. It is an opaque stone with a hardness of 5 to 6 on the Mohs scale, making it relatively soft and susceptible to scratching. Its chemical formula is a hydrated copper aluminum phosphate.
Tanzanite is prized for its strong pleochroism, meaning it shows different colors when viewed from different angles—a phenomenon best observed as blue and violet. It has a hardness of 6.5 to 7 on the Mohs scale, making it more durable than turquoise but still requiring careful handling. It is a variety of zoisite, with a chemical composition of calcium aluminum hydroxyl silicate.
Zircon is one of the hardest natural gemstones, with a Mohs hardness of 7.5, and it possesses a high refractive index, which gives it exceptional brilliance and fire, rivaling that of diamond. Its most common color in jewelry is a bright, clear blue. It is a zirconium silicate (ZrSiO₄).
Blue Topaz is a relatively hard and durable gem, rating an 8 on the Mohs scale, making it an excellent choice for all types of jewelry. Its color can range from a light sky blue to a deep, saturated London Blue. Its chemical formula is Al₂SiO₄(F,OH)₂.
A summary of key properties is provided in the table below:
| Gemstone | Mineral Family | Chemical Formula | Mohs Hardness | Key Feature |
|---|---|---|---|---|
| Turquoise | Phosphate | CuAl₆(PO₄)₄(OH)₈·4H₂O | 5 - 6 | Opaque, often with matrix |
| Tanzanite | Zoisite | Ca₂Al₃(SiO₄)₃(OH) | 6.5 - 7 | Strong pleochroism (blue/violet) |
| Zircon | Zircon | ZrSiO₄ | 7.5 | High refractive index, great fire |
| Blue Topaz | Silicate | Al₂SiO₄(F,OH)₂ | 8 | High durability, deep blue color |
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, December's birthstones are deeply imbued with symbolic meaning and metaphysical beliefs, many of which have been passed down through generations. Turquoise is widely regarded as a stone of protection, grounding, and calm. It is seen as a steadying force, offering a sense of tranquility and security to its wearer. Many believe it can help to shield against negative energies and promote overall well-being.
Tanzanite, with its modern discovery, carries symbolism related to personal growth and transformation. It is often associated with new beginnings and is believed to enhance intuition and spiritual perception. Its unique color is said to represent a bridge between the physical and spiritual worlds, encouraging a higher consciousness and a clearer understanding of one's purpose.
Zircon is associated with mental clarity, wisdom, and balance. It is believed to help its wearer see things with a clearer perspective, promoting wise decision-making and self-confidence. In some traditions, it is thought to aid in overcoming negative thoughts and bringing prosperity.
Blue Topaz is linked to love, fidelity, and calmness. It is considered a stone of peaceful communication and is believed to help express one's thoughts and feelings clearly and lovingly. It is also associated with serenity and is thought to be a powerful tool for meditation and relaxation, helping to calm the mind and soothe the emotions.
Care and Cleaning
Proper care is essential to maintain the beauty and integrity of any gemstone. Due to their varying levels of hardness and stability, the December birthstones require different approaches to cleaning and storage.
Turquoise is the most delicate of the four due to its porosity and lower hardness. It can be easily scratched and can absorb chemicals, lotions, and even skin oils, which can cause discoloration over time. It should be cleaned with warm water, a mild soap, and a soft cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals. Store it separately to prevent scratches.
Tanzanite is also relatively delicate for a gemstone. While its hardness is moderate, it has perfect cleavage in one direction, meaning it can split if struck with force. It is sensitive to rapid temperature changes. Cleaning should be done with warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaners.
Zircon is quite hard but can be brittle due to its cleavage. Some zircon may also be heat-treated, so it is wise to avoid extreme temperatures. It is generally safe to clean with warm, soapy water and a soft brush. Ultrasonic cleaners are usually safe, but it is best to exercise caution, especially if the stone has any fractures.
Blue Topaz is quite durable due to its hardness and lack of cleavage, making it relatively easy to care for. It can be safely cleaned with warm, soapy water and a soft brush. It is also generally safe in an ultrasonic cleaner. However, as it is often treated with irradiation to achieve its blue color, it is advisable to avoid prolonged exposure to extreme heat, which could potentially alter its color.
Conclusion
December's birthstones offer a remarkable diversity that sets them apart from all other months. From the ancient, protective talisman of Turquoise to the modern, transformative allure of Tanzanite, each gem provides a unique connection to the natural world and human history. The brilliant fire of Zircon rivals that of diamond, while the deep, serene blue of Topaz offers durability and symbolic love. Together, they represent a full spectrum of winter’s beauty, from icy skies to deep twilight. For those born in December, the choice of a birthstone is not merely a matter of color preference but an opportunity to connect with a gem rich in geological significance, historical lore, and personal meaning. By understanding their individual properties and stories, one can fully appreciate the treasure chest of gems that this final month of the year provides.