When the final month of the year arrives, marked by winter's chill and festive celebrations, the gemstones associated with December are often described in terms of their cool, captivating hues. From the ancient, opaque blue of turquoise to the fiery brilliance of zircon and the velvety blue-violet of tanzanite, December offers a unique and diverse selection of birthstones. This article delves into the rich history, geological origins, gemological properties, and cultural significance of these three primary December birthstones, providing a detailed guide for enthusiasts, collectors, and those seeking a meaningful gemstone connection.
History and Lore
The tradition of assigning specific gemstones to birth months has deep historical roots, often tracing back to biblical references such as the breastplate of Aaron or the foundations of the New Jerusalem. Over centuries, various cultures and institutions have developed their own lists, resulting in a fascinating array of birthstones for each month. For December, this history is particularly layered, with multiple gems vying for the title across different eras and traditions.
Turquoise: An Ancient Talisman Turquoise stands as one of the oldest and most storied gemstones associated with December. Its name itself tells a tale of trade and travel; the stone was known as turkis or turkeystone, derived from the fact that it reached European markets through Turkey, having originated in Persia and along the Sinai Peninsula. From the earliest times, turquoise was a favored gem for amulets. Its relative ease of carving allowed it to be shaped into various forms and inscribed with protective symbols. It was widely believed to possess the power to ward off danger and bring good fortune. In many cultures, it was a stone of love and fidelity, prized by lovers and married couples for its purported ability to protect relationships and preserve friendship when given as a gift. A common belief held that the stone could warn its wearer of approaching illness or danger by losing its color and becoming pale.
Ancient civilizations held turquoise in particularly high regard. The pharaohs and rulers of ancient Egypt adorned themselves with it, and Chinese artisans were carving turquoise more than 3,000 years ago. For the Incas and Mayas, it was a sacred offering to their gods. In Tibet, turquoise was considered a birthstone of fortune, health, and success, and was so valued that it was often used as currency. Among Native American tribes of the Southwestern United States, the stone was associated with youth and strength. The Apache believed that turquoise could be found by following a rainbow to its end, linking the gem to celestial phenomena.
Zircon: The December Standard Zircon has a long history as a traditional December birthstone. In the United States, its status was formally cemented in 1952 when the Jewelers of America (JA) updated the official birthstone list, replacing lapis lazuli with zircon for the month of December. This decision solidified zircon's place as a modern birthstone, prized for its exceptional brilliance and fire, which rivals that of diamond. While its historical lore is less documented in the provided sources compared to turquoise, its adoption into the modern list highlights its importance in contemporary gemology and jewelry.
Tanzanite: The Modern Contender Tanzanite is the newest addition to the December birthstone family. Discovered in the 20th century, it was quickly recognized for its unique color and was added to the official list of modern birthstones in 2002. Its inclusion reflects a dynamic tradition that evolves with new discoveries. Tanzanite's rise to prominence is a testament to its captivating beauty and the gemological community's ability to identify and promote exceptional new stones.
A Broader Historical Tapestry The historical landscape for December birthstones is complex. Beyond the primary three, other gems have been associated with the month through various calendars and traditions. Bloodstone (heliotrope) was a traditional birthstone for December as far back as the 15th century. Ruby, chrysoprase, and lapis lazuli also appear in ancient and traditional lists. Onyx holds significance in the old Tibetan calendar, and cat's eye is noted in Indian tradition. Furthermore, specific spiritual systems assign different stones: Beryl is linked to the guardian angel Humiel for December, while Sapphire is the birthstone for the special apostle Paul, who is associated with the month. Sagittarius (spanning late November and December) and Capricorn (late December) also have their own astral birth gems, including Emerald and Chalcedony. This multiplicity underscores that the choice of a December birthstone is not always singular but can be guided by personal, cultural, or spiritual connection.
Geological Formation and Sources
Understanding where these gemstones come from provides insight into their rarity and value. Each of the primary December birthstones forms under distinct geological conditions.
Turquoise: A Hydrated Mineral Turquoise is not a single mineral but a hydrous phosphate of copper and aluminum. It forms in arid regions where acidic, copper-rich groundwater seeps through and reacts with minerals containing aluminum and phosphorus, such as feldspars. Over millennia, this process creates veins and nodules of turquoise within the host rock, often accompanied by a dark, veined matrix. The color, ranging from blue to green, is primarily determined by the amount of copper (blue) and iron (green) present.
Major historical and modern sources for turquoise include: * Persia (modern-day Iran): Historically one of the most renowned sources, producing stones with a distinctive sky-blue color. * Sinai Peninsula: An ancient source for turquoise, used extensively by Egyptian civilizations. * Southwestern United States: A significant modern source, particularly in Arizona, New Mexico, and Nevada, producing stones prized by Native American artisans and the global market. * China: A source of turquoise for millennia, with documented carving traditions dating back over 3,000 years.
Zircon: A High-Temperature Mineral Zircon is a zirconium silicate (ZrSiO₄) that forms in igneous and metamorphic rocks. It is one of the oldest minerals on Earth, with crystals found in ancient sediments. Zircon crystals typically form in high-temperature environments, such as in pegmatites or during the cooling of magmatic rocks. They are often found as accessory minerals in granite and other plutonic rocks.
Key sources for gem-quality zircon include: * Cambodia: Known for producing fine blue and golden-brown zircon. * Sri Lanka: A historic source for a variety of zircon colors. * Myanmar (Burma): Produces zircon, often associated with its famous ruby deposits. * Australia: A significant source of zircon, though often for industrial use, some gem-quality material is recovered. * Brazil, Nigeria, and Tanzania: Also contribute to the global supply of zircon.
Tanzanite: A Single-Source Gem Tanzanite is a variety of the mineral zoisite (Ca₂Al₃(SiO₄)₃(OH)), colored by trace amounts of vanadium. Its formation is exceptionally rare. It is found in only one location on Earth: the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. The gem formed under unique geological conditions involving the metamorphism of specific rocks under heat and pressure, a process that is believed to have occurred approximately 585 million years ago. The limited geographic source makes tanzanite significantly rarer than many other gemstones, and its availability is finite.
Gemological Properties
The value and durability of a gemstone are largely determined by its physical and chemical properties. The following table summarizes key gemological data for turquoise, zircon, and tanzanite based on standard gemological references.
| Property | Turquoise | Zircon | Tanzanite (Zoisite) |
|---|---|---|---|
| Chemical Formula | Hydrated copper aluminum phosphate (CuAl₆(PO₄)₄(OH)₈·4H₂O) | Zirconium silicate (ZrSiO₄) | Calcium aluminum silicate hydroxide (Ca₂Al₃(SiO₄)₃(OH)) |
| Crystal System | Triclinic | Tetragonal | Orthorhombic |
| Hardness (Mohs Scale) | 5 - 6 | 7.5 | 6 - 7 |
| Refractive Index | 1.610 - 1.650 | 1.92 - 1.98 (varies with color) | 1.69 - 1.70 |
| Specific Gravity | 2.60 - 2.90 | 4.60 - 4.70 | 3.35 |
| Luster | Waxy to subvitreous | Adamantine (brilliant) | Vitreous (glass-like) |
| Color | Blue to green, often with matrix | Colorless, yellow, brown, red, blue, green | Blue to violet-blue, often with pleochroism |
| Transparency | Semi-translucent to opaque | Transparent to translucent | Transparent to translucent |
| Cleavage | None | Imperfect | Good in one direction |
Turquoise: As a relatively soft and porous stone (hardness 5-6), turquoise requires careful handling. Its opacity and characteristic matrix are key identifiers. The quality is often graded by color (e.g., "robin's egg blue") and the presence of matrix.
Zircon: Not to be confused with the synthetic cubic zirconia, natural zircon is a distinct and valuable gem. Its high refractive index and strong dispersion (fire) give it exceptional brilliance, making it a popular diamond simulant. However, its hardness (7.5) makes it more durable than many colored stones. Zircon can be heat-treated to improve or change its color, particularly to produce blue or colorless varieties.
Tanzanite: Known for its strong trichroism (displaying three different colors—blue, violet, and red-violet—when viewed from different angles), tanzanite's most desirable color is a rich, saturated blue-violet. Most tanzanite is heat-treated to achieve this color, as the natural stone often appears brownish. With a hardness of 6 to 7, it is durable enough for jewelry but requires protection from hard knocks. Its pleochroism is a defining characteristic that gemologists use for identification.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, these gemstones are imbued with layers of meaning and symbolic power, derived from centuries of cultural practice and personal belief.
Turquoise: The Stone of Protection and Well-being Turquoise is universally regarded as a stone of protection, healing, and good fortune. Its lore is rich with metaphysical claims: * Protection: Historically used as an amulet against violence, accidents, and negative energy. It was believed to break when it had absorbed a fatal blow meant for the wearer. * Health and Vitality: Associated with overall wellness, it was thought to strengthen the body and ward off illness. In some traditions, it was believed to be a barometer of health, changing color to signal illness. * Emotional Balance: Modern metaphysical beliefs suggest turquoise relieves mental tension, promotes calmness, and fosters creative expression. * Communication and Friendship: As a stone of communication, it is believed to encourage honest speech and preserve the bonds of friendship.
Zircon: The Stone of Wisdom and Prosperity While its metaphysical lore is less extensive in the provided sources, zircon has been associated with several positive attributes throughout history: * Wisdom and Honor: It is often linked to clarity of thought, spiritual grounding, and the attainment of wisdom. * Prosperity: Believed to attract abundance, success, and honor to the wearer. * Emotional Balance: Some beliefs hold that zircon can help alleviate depression and enhance emotional stability.
Tanzanite: The Stone of Transformation and Higher Consciousness As a newer gem, tanzanite's metaphysical properties are largely defined by its modern discovery and unique energy: * Transformation: Its intense color and rarity are associated with significant life changes and spiritual awakening. * Higher Consciousness: Often linked to the third eye and crown chakras, it is believed to facilitate meditation, psychic abilities, and a connection to higher realms. * Calm and Clarity: Its soothing blue-violet hue is thought to promote a sense of peace, calm, and mental clarity.
Care and Cleaning
Proper maintenance is essential to preserve the beauty and longevity of any gemstone. The care instructions for turquoise, zircon, and tanzanite differ significantly due to their contrasting physical properties.
Turquoise Care: Due to its porosity and relative softness, turquoise is susceptible to damage from chemicals, heat, and abrasion. * Cleaning: Use only mild soap, lukewarm water, and a soft brush. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals (including perfumes, lotions, and household cleaners), which can damage the stone's surface and color. * Storage: Store separately from harder stones to prevent scratching. Avoid prolonged exposure to direct sunlight or heat, which can cause fading or cracking. * Handling: Remove turquoise jewelry before engaging in physical activities, gardening, or household chores to protect it from impacts and dirt.
Zircon Care: Zircon is harder but can be brittle due to its poor cleavage. * Cleaning: Safe to clean with warm soapy water and a soft brush. Ultrasonic cleaners are generally safe, but caution is advised for stones with inclusions. Avoid sudden temperature changes, as zircon can fracture. * Storage: Store in a soft cloth or separate compartment to prevent scratching other gems or being scratched by harder stones (like diamonds or sapphires).
Tanzanite Care: Tanzanite's good cleavage in one direction makes it vulnerable to breakage from sharp blows. * Cleaning: Clean with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaners, as vibrations and heat can cause the stone to fracture. * Handling: Due to its cleavage, tanzanite should be handled with care. It is best suited for jewelry settings that protect the stone, such as bezels or pendants, rather than rings that are exposed to daily wear and impact.
Conclusion
The birthstones of December—turquoise, zircon, and tanzanite—offer a remarkable spectrum of color, history, and meaning. From the ancient, protective talisman of turquoise to the brilliant, fiery zircon and the transformative, modern tanzanite, each gem provides a unique connection to the month's wintery essence. Their diverse origins, from single-source tanzanite in Tanzania to globally distributed turquoise and zircon, speak to the Earth's geological wonders. While their gemological properties differ, requiring specific care to maintain their splendor, their shared association with December provides a rich tapestry of choice for anyone born in the final month of the year. Whether selected for its historical significance, metaphysical properties, or sheer beauty, a December birthstone is a timeless treasure that carries the legacy of centuries and the promise of enduring elegance.