The twelfth month of the year is uniquely distinguished in the world of gemology by its abundance of official and alternative birthstones. While many months are assigned a single gem, December is associated with a quartet of captivating blue stones: Turquoise, Tanzanite, Zircon, and Topaz. This rich selection offers a diverse palette of colors, histories, and properties, providing those born in this winter month with a remarkable array of choices. The traditional association with the color blue reflects the cool tones of the season, yet the specific hues range from the soft, sky-blue of Turquoise to the deep, violet-blue of Tanzanite and the brilliant, clear blue of Zircon. This comprehensive guide will explore the distinct characteristics of each of these December birthstones, delving into their geological origins, gemological properties, historical significance, and the symbolism they have accumulated over centuries. By examining each stone individually, we can appreciate the unique qualities that make them cherished gems for collectors, jewelry enthusiasts, and anyone born under the sign of December.
The Four Stones of December: An Overview
December holds the distinction of having the most birthstones of any month, a fact that has evolved over time through standardization and market demand. The official list, as recognized by trade organizations and gemological authorities, has expanded from its traditional core to include modern favorites.
The traditional birthstones for December are Turquoise, Zircon, and Tanzanite. These three are frequently cited together, each representing a different facet of the color blue. Turquoise offers an opaque, often matrix-veined blue-green. Zircon presents a brilliant, fiery blue, while Tanzanite provides a pleochroic violet-blue that shifts in the light. In the United States, Blue Topaz is also widely considered a modern birthstone for the month, adding a durable and affordable option to the lineup.
This multiplicity of choice is a relatively modern development. The standardization of birthstones began in 1912 with the National Association of Jewelers, which sought to create a consistent list for commercial purposes. Subsequent updates have added stones to reflect new discoveries and changing tastes. Zircon was officially added to the December list in 1952, and Tanzanite was included in 2002, a testament to its rising popularity and significance in the gem market. The addition of Blue Topaz, while not part of the official list maintained by some gemological institutes, is a frequent inclusion in modern jewelry, offering consumers more flexibility in price, durability, and style.
Turquoise: The Ancient Sky Stone
Turquoise is arguably the most historically significant of the December stones, with a lineage that stretches back millennia. Its name provides a clue to its long and storied journey across continents. The word "Turquoise" is derived from the French phrase pierre turquoise, meaning "stone of Turkey." This name was bestowed upon the gem when it was brought to Europe from Turkish bazaars by traders, though the stone’s origins lie much farther east.
Geological Formation and Sources Turquoise is a secondary mineral that forms when water containing copper and aluminum seeps through pre-existing rock. This process, known as percolation, occurs in arid regions where the groundwater can react slowly with minerals in the bedrock over millions of years. The presence of copper is responsible for the stone’s characteristic blue color, while traces of iron can shift the hue toward green. The dark lines and shapes often seen within Turquoise are not flaws; they are fragments of the host rock, known as matrix, that become embedded in the gem as it forms. This matrix can create intricate, web-like patterns that are highly valued for their uniqueness. While specific mining locations were not detailed in the provided materials, the geological formation process described is universal for Turquoise deposits.
Gemological Properties Turquoise is an opaque gem, meaning light does not pass through it. Its beauty lies in its rich, even coloration and the distinctive matrix patterns that many specimens exhibit. It is prized for its unique sky-blue to greenish-blue hues. Unlike many other gemstones, Turquoise is valued for its opacity rather than its transparency. It is a relatively soft and porous stone, which makes it susceptible to damage from chemicals, heat, and even the oils from human skin. This requires careful handling and maintenance to preserve its color and integrity over time.
History and Lore The lore surrounding Turquoise is as rich as its color. It has been a talisman for kings, warriors, and travelers for thousands of years. Ancient Egyptians adorned themselves with Turquoise jewelry, and it was inlaid in the burial masks of pharaohs, such as Tutankhamun. The stone was believed to offer protection, good fortune, and health. Its association with protection is a recurring theme across many cultures. For many, it was considered a conduit to the divine and a stone that could change color to warn its owner of impending danger or illness. Its symbolism remains strong today, linking the modern wearer to a deep history of human belief in the power of the natural world.
Tanzanite: A Modern Marvel of Violet-Blue
In stark contrast to the ancient history of Turquoise, Tanzanite is a distinctly modern gem, yet it has quickly secured a place of honor as one of December’s most coveted birthstones. Its story is one of recent discovery and rapid ascent to international fame.
Geological Formation and Sources Tanzanite’s rarity is a direct result of its unique and geologically limited origin. It is found in only one place on Earth: a small, four-square-kilometer mining area in the Merelani Hills of northern Tanzania. This exclusivity makes it at least a thousand times rarer than Diamond. Tanzanite is a variety of the mineral zoisite and owes its mesmerizing color to heat and trace amounts of vanadium. The geological conditions required for its formation were so specific that they occurred only in this single location, making it a true geological wonder.
Gemological Properties The most captivating property of Tanzanite is its pleochroism—the ability to display different colors when viewed from different crystallographic directions. A single stone can appear as a deep, rich blue from one angle and a vibrant violet or reddish-purple from another. This dynamic quality gives the gem an ever-changing, lively appearance. It is often heat-treated to enhance its blue and violet hues, a standard and stable practice in the gem trade. While beautiful, Tanzanite is not particularly hard, ranking at 6 to 6.5 on the Mohs hardness scale, making it more suitable for earrings and pendants than for rings that might endure daily knocks.
Symbolism and Modern Significance Because of its recent discovery in 1967, Tanzanite does not have the ancient lore of Turquoise. Instead, its symbolism is tied to themes of transformation, new beginnings, and a modern sense of elegance. It is often associated with the unique and sophisticated individual. Its value is directly linked to its rarity and its singular source, making it the most valuable and expensive of the four December birthstones. Tanzanite represents a new chapter in the long story of gemstones, a gem for a new millennium.
Zircon: The Fiery and Misunderstood Blue
Zircon is one of the oldest minerals on Earth, yet it is often one of the most misunderstood due to its similarity in name to the synthetic cubic zirconia. True Zircon is a natural gemstone with exceptional brilliance and fire, and its blue variety is a traditional December birthstone.
Geological Formation and Sources Zircon is a mineral that forms in the Earth’s crust during the cooling of magma. It is found in many places around the world, often as a detrital mineral in sedimentary deposits. The brilliant blue color of the birthstone variety is typically the result of heat treatment, which can transform brownish zircon crystals (common in nature) into the vivid blue gems seen in jewelry. This process is stable and widely accepted in the industry.
Gemological Properties Blue Zircon is renowned for its exceptional brilliance and fire, which can rival that of Diamond. It has a high refractive index, meaning it bends light significantly, creating a dazzling sparkle. On the Mohs hardness scale, it ranks at 6.5 to 7.5, making it reasonably durable, though it can be brittle. Its clarity is typically very good, with stones often being eye-clean. The color of Blue Zircon is typically a bright, clear, and vibrant blue, distinct from the violet-blue of Tanzanite and the opaque blue-green of Turquoise.
History and Symbolism The name Zircon is believed to be derived from the Arabic word zarkun, meaning "vermillion" or "gold-colored," which may refer to the brown or golden hues of some natural crystals. Historically, Zircon has been associated with wisdom, clarity, and honor. It was believed to promote sound sleep and ward off evil spirits. Its association with clarity and balance makes it a meaningful stone for those seeking focus and stability in their lives. Despite the confusion with its synthetic counterpart, natural Zircon is a gem of great beauty and historical importance.
Blue Topaz: The Modern and Durable Alternative
While not always listed on the most traditional birthstone lists, Blue Topaz has become a prominent and popular modern birthstone for December, particularly in the United States. Its appeal lies in its brilliant color, excellent durability, and accessibility.
Geological Formation and Sources Topaz is a silicate mineral that forms in igneous rocks, such as granite and rhyolite, from fluorine-rich vapors during the final stages of magma cooling. Natural blue topaz is exceptionally rare. The vivid blue Topaz seen in jewelry today is almost always the result of irradiation and heat treatment of colorless or pale topaz crystals. Major sources for Topaz include Sri Lanka, Brazil, Mexico, Nigeria, and the United States. In fact, Blue Topaz is the official state gem of Texas.
Gemological Properties Blue Topaz is the most durable of the December birthstones. It ranks at an 8 on the Mohs hardness scale, making it an excellent choice for rings and other jewelry intended for everyday wear. It is also a very brilliant stone with good clarity. The color of Blue Topaz can range from pale, almost translucent sky blue (known as Sky Topaz) to a deeper, more saturated aqua or Swiss Blue. Its combination of durability, brilliance, and vibrant color has made it a favorite of jewelers and consumers alike.
Symbolism and Lore The name "Topaz" comes from the Greek "Topazios," the ancient name for an island in the Red Sea (now St. John's Island) where a yellow stone was once mined. However, the stone found on that island was later identified as Peridot, not Topaz. Despite this mix-up, the name endured. Historically, Topaz was believed to have cooling properties and to dispel anger and enchantment. It was also associated with friendship and good health. Blue Topaz, in particular, is often given as a token of affection and is believed to promote clear communication and emotional balance.
Care and Cleaning for December Birthstones
Given the diverse physical properties of the four December stones, proper care is essential to maintain their beauty and longevity. Each stone requires a slightly different approach.
- Turquoise: As a porous and relatively soft stone (approx. 5-6 on the Mohs scale), Turquoise is delicate. It should be protected from chemicals, cosmetics, and even prolonged exposure to skin oils, which can cause discoloration. Clean it gently with a soft, dry cloth. Avoid ultrasonic cleaners and steam cleaning.
- Tanzanite: With a hardness of 6 to 6.5, Tanzanite is susceptible to scratching and chipping. It is best suited for pieces that are not subject to impact, like earrings and pendants. Clean with warm water, a mild soap, and a soft brush.
- Zircon: While fairly hard (6.5-7.5), Zircon is brittle and can be easily chipped if knocked against a hard surface. It is generally safe to clean with warm soapy water and a soft brush, but avoid ultrasonic cleaners and sudden temperature changes, which can cause fractures.
- Blue Topaz: As the hardest of the group (8 on the Mohs scale), Blue Topaz is quite durable. It can be safely cleaned with warm soapy water and a soft brush. It is also generally safe in an ultrasonic cleaner, though it is always best to check with a professional jeweler first, especially if the stone has been fracture-filled.
Conclusion
The birthstones of December offer a remarkable spectrum of blue, from the earthy, opaque tones of Turquoise to the shifting violet-blue of Tanzanite, the brilliant sparkle of Zircon, and the clear, durable hue of Blue Topaz. This variety is a direct reflection of the month's unique character, providing a gem for every preference and style. The history of these stones spans from the ancient world, where Turquoise was a symbol of protection, to the modern era, where Tanzanite represents a rare and recent geological marvel. Their properties are as diverse as their origins, ranging from the soft and porous nature of Turquoise to the exceptional hardness of Blue Topaz. For those born in December, the choice of a birthstone is not a simple one, but rather an opportunity to select a gem that resonates with personal history, aesthetic taste, and a connection to the natural world’s incredible artistry. Each stone, in its own way, captures the cool brilliance of winter and serves as a lasting emblem for the twelfth month of the year.