For those born in the final month of the year, the selection of birthstones is as varied and vibrant as the season itself. December is uniquely associated with four distinct gemstones: Turquoise, Tanzanite, Zircon, and Blue Topaz. While most months are assigned a single gem, December offers a rich palette of blues, from the soft sky hues of ancient stones to the deep, shifting violet-blues of modern discoveries. This abundance provides individuals born under the zodiac signs of Sagittarius and Capricorn with a diverse range of choices, each possessing its own unique history, geological origin, and symbolic meaning. The traditional stones, Turquoise and Zircon, speak to centuries of human adornment, while the more recent additions, Tanzanite and Blue Topaz, reflect the evolution of gemstone popularity and market demand in the 20th and 21st centuries. This guide explores the geological formation, gemological properties, historical lore, and cultural significance of these four remarkable birthstones, drawing exclusively from established data to provide an expert overview for enthusiasts, collectors, and buyers.
History and Lore
The historical narrative of December's birthstones is a tale of two eras: the ancient and the modern. Turquoise stands as the most venerable of the group, recognized as one of the world's oldest known gemstones. Its use in adornment and ritual spans millennia and continents. The very name "Turquoise" is a testament to its long and complex trade routes, derived from the French phrase pierre turquoise, meaning "stone of Turkey." This name was applied when the gem was brought to Europe from Turkish bazaars, though its origins lie far to the east. Cultures across the globe have held this stone in high esteem. For many, it is a sacred stone, revered for its protective powers and connection to spiritual well-being. Its traditional significance is deeply rooted in concepts of friendship, protection, and good fortune, making it a powerful amulet and a meaningful gift.
Zircon, too, carries a rich historical legacy, though its story is often intertwined with that of other gemstones due to its remarkable brilliance. For centuries, the sparkling quality of zircon led to it being mistaken for diamond. This confusion is particularly notable in medieval Europe, where the "Mali Diamond" was, in fact, a large zircon. While the provided sources do not detail the specific historical timeline of zircon's use as a birthstone, its association with wisdom and clarity is a long-standing tradition. It is a stone that has been appreciated not just for its diamond-like fire but also for the metaphysical properties it is said to bestow upon its wearer.
In stark contrast to these ancient gems, Tanzanite is a product of the modern era. It is a recent addition to the world of fine gemstones, having been discovered in the 20th century. Its story is one of sudden appearance and rapid ascent to fame. Discovered in a single, limited geographic location in Tanzania, this gem captivated the global market with its unprecedented color. The official recognition of Tanzanite as a December birthstone occurred in 2002, when the Jewelry Industry Council of America added it to the list, acknowledging its growing popularity and unique appeal. Its symbolism is accordingly modern, representing transformation, new beginnings, and a forward-looking perspective.
Blue Topaz, while not as ancient as Turquoise or Zircon in its recognized birthstone status, has a mysterious and long-standing history. Its exact historical origins are unknown, with evidence of the gem appearing throughout history in various parts of the world. The gem gained significant prominence in the 1950s when it was added to the list of birthstones, a move that expanded the options available for December birthdays. Its journey from a lesser-known gem to a mainstream favorite was solidified by its availability and durability, making it a practical and beautiful choice for everyday jewelry. Today, it holds the distinction of being the official state gem of Texas, a testament to its cultural integration in the modern United States.
The evolution of the December birthstone list itself is a fascinating historical footnote. The standardization of birthstones in the United States began in 1912 with the National Association of Jewelers, which sought to combine tradition with commercial practicality. The list has been updated several times since, reflecting the dynamic nature of the gem market. Zircon was officially added in 1952, and Tanzanite's inclusion in 2002 marks the most recent major update. This evolution suggests that the abundance of choices for December was a deliberate expansion, possibly to offer consumers a wider variety of colors, styles, and price points.
Geological Formation and Sources
Each of December's four birthstones has a unique geological story, dictating where they are found and the conditions under which they form.
Turquoise is not a mineral that crystallizes from molten rock deep within the Earth. Instead, it is a secondary mineral formed through a process of precipitation. It occurs when groundwater, rich in copper, seeps through and percolates into bedrock. This copper-bearing water reacts with minerals containing aluminum and phosphorus over vast periods. The result is the formation of an opaque stone in stunning shades of blue and green. The distinctive dark lines and webbing seen within many turquoise stones, known as the "matrix," are actually fragments of the surrounding host rock that became incorporated during its formation. Major sources for this gem include Iran, the United States (particularly the Southwest), Tibet, and India.
Tanzanite is remarkable for its extreme geological rarity. It is a variety of the mineral zoisite and is found in only one known location on the planet: a tiny, four-square-kilometer area in the Merelani Hills of northern Tanzania. This exclusivity is the primary reason for its high value and expense. The gem's formation is linked to the tectonic uplift of the East African Rift, a process that created the unique conditions necessary for zoisite crystals to be transformed into the vibrant violet-blue stones we know as Tanzanite through a combination of intense heat and pressure.
Zircon is one of the oldest minerals on Earth, with crystals found in Australia that are over 4.4 billion years old. It is a zirconium silicate that crystallizes from magma as it cools. It is a common mineral found in many types of rocks, but gem-quality zircon is much rarer. While the provided sources do not specify current mining locations for zircon, its global distribution is well-established in geological literature.
Blue Topaz is mined in several countries around the world, reflecting its wider geological distribution. The sources list Sri Lanka, Brazil, Mexico, Nigeria, and the U.S. as locations where it is found. Topaz itself is a silicate mineral that forms in igneous rocks, particularly in silica-rich magmas and the voids within them. The blue color in most commercial blue topaz is the result of a treatment process involving irradiation and heat, which alters the crystal's color centers. Naturally occurring blue topaz of a deep, saturated color is exceptionally rare.
Gemological Properties
Understanding the physical and chemical properties of these gems is crucial for appreciating their unique characteristics and for making informed decisions about their use in jewelry. The most significant factor for durability is hardness, measured on the Mohs scale.
| Gemstone | Mohs Hardness | Chemical Composition | Color Range | Key Characteristics |
|---|---|---|---|---|
| Turquoise | 5 – 6 | Hydrated phosphate of copper and aluminum | Sky blue, greenish-blue | Opaque, often contains a dark matrix |
| Tanzanite | Not specified | Calcium aluminum hydroxyl sorosilicate | Rich violet-blue | Trichroic (shows three colors), pleochroic |
| Zircon | Not specified | Zirconium silicate (ZrSiO₄) | Bright, clear blue | High refractive index, great brilliance |
| Blue Topaz | 8 | Aluminum silicate fluoride hydroxide | Various shades of blue | Most durable of the four, often treated |
Turquoise has a Mohs hardness of 5 to 6, making it a relatively soft and porous gem. This means it can be susceptible to scratching, chemicals, and heat. Its opaque nature and characteristic matrix are defining features. High-quality turquoise is valued for its even, vibrant color, free from heavy matrix or discoloration.
Tanzanite is noted for its fragility, though its specific hardness is not listed in the provided sources. It is prized for its unique and intense violet-blue hue, which is a result of its strong pleochroism—the ability to show different colors when viewed from different angles. A well-cut tanzanite will display a rich blue in one direction and a purplish-red or burgundy in another, making it a visually dynamic stone.
Zircon is celebrated for its exceptional brilliance and fire, which can rival that of a diamond. This is due to its high refractive index. While the sources do not specify its hardness, it is known in gemology to be brittle, meaning it can chip if knocked hard. The "bright, clear blue" mentioned is a highly sought-after color for this gem.
Blue Topaz stands out for its superior durability. With a Mohs hardness of 8, it is the hardest and most resilient of all the December birthstones, making it an excellent choice for rings and other jewelry that will be worn daily. Its hardness, combined with its availability in large, clean crystals, has made it a popular and affordable gemstone in the modern jewelry market.
Symbolism and Metaphysical Beliefs
The allure of gemstones extends beyond their physical beauty to the meanings and powers ascribed to them throughout history. Each of December's gems carries a distinct symbolic weight.
Turquoise is fundamentally a stone of protection. It has long been believed to ward off negative energy and bring good fortune to the wearer. Its association with calmness and truth makes it a talisman for clarity of thought and peaceful communication. In many cultures, it is also a symbol of friendship, offered as a gift to ensure a long and loyal bond.
Tanzanite, as a modern discovery, is imbued with modern symbolism. It is strongly linked to transformation, encouraging spiritual awakening and new beginnings. It is considered a stone of purpose, helping individuals to move forward with confidence and embrace change in their lives.
Zircon is associated with wisdom and clarity, both of mind and spirit. It is believed to promote self-confidence and a sense of balance and stability. For those seeking to organize their thoughts or find a clear path forward, zircon is said to be a helpful guide.
Blue Topaz is often associated with calmness, clarity, and communication. It is believed to soothe frayed nerves and promote honest and open expression. Its cool blue color is inherently calming, and its symbolism reflects this serene quality.
Care and Cleaning
The varying hardness and porosity of these gems necessitate different approaches to care and cleaning. Proper maintenance is essential to preserving the beauty and longevity of birthstone jewelry.
Turquoise, due to its low hardness and porosity, requires the most care. It is susceptible to damage from chemicals, including those found in soaps, cosmetics, and even skin oils. To clean turquoise, simply use a soft, dry cloth. Avoid soaking it in water or using any type of chemical cleaner. It should be stored carefully to prevent scratching by harder gems.
Tanzanite is described as fragile. While it can be cleaned with warm, soapy water and a soft brush, it should be handled with care to avoid sharp blows that could cause chipping or fracture. Its relative softness makes it less suitable for rings worn on the hand daily, and it is often better suited for pendants or earrings.
Zircon, while brilliant, is known to be brittle. It can be chipped by a hard impact. It is generally safe to clean with warm, soapy water and a soft brush, but it should be protected from rough treatment.
Blue Topaz is the most durable of the group, making it the easiest to care for. Its hardness of 8 means it is resistant to scratching and daily wear. It can be safely cleaned with warm, soapy water and a soft brush. However, like all gemstones, it should be protected from extreme temperature changes and harsh chemicals to maintain its luster.
Conclusion
December's birthstones offer a remarkable diversity that is unmatched by any other month. From the ancient, protective Turquoise to the brilliant, wisdom-symbolizing Zircon, and from the rare, transformative Tanzanite to the durable, serene Blue Topaz, each gem provides a unique story and aesthetic. This variety ensures that anyone born in December can find a stone that not only matches their personal style but also resonates with their individual journey. Whether one is drawn to the historical depth of ancient gems or the vibrant allure of modern discoveries, the birthstones of December provide a rich and brilliant legacy, capturing the cool beauty and profound significance of the year's final month.