The month of December is uniquely distinguished in the world of gemology by its extensive and diverse array of birthstones. While most months are associated with a single gem, December boasts four distinct and celebrated stones: Turquoise, Zircon, Tanzanite, and Blue Topaz. This remarkable collection offers a spectrum of blue hues, from the soft, sky-like tones of turquoise to the deep, violet-blue of tanzanite, mirroring the icy skies and deep twilight of the winter season. Each of these gemstones possesses a unique history, a specific geological origin, and a set of gemological properties that make it suitable for different types of jewelry and personal preferences. This comprehensive guide explores the rich tapestry of information surrounding these four blue treasures, delving into their historical significance, geological formation, physical characteristics, and cultural symbolism, providing an authoritative resource for gemstone enthusiasts, collectors, and prospective buyers.
The evolution of this multi-gemstone tradition is a fascinating story of both custom and commerce. The modern list of birthstones was largely standardized in 1912 by the National Association of Jewelers to create a consistent and practical guide for the jewelry trade. However, the list has continued to evolve. In 1952, the Jewelry Industry Council of America updated the list, adding zircon to December’s offerings. More recently, in 2002, tanzanite was officially added, reflecting the gem's rising popularity and significance in the market. The reasons for December having the most birthstones are varied; some sources suggest it was to provide a wider range of affordable and durable options for consumers, while others point to the desire to incorporate newly discovered and commercially viable gemstones into the traditional calendar. Regardless of the reason, this abundance provides a remarkable "treasure chest" of options, allowing individuals to choose a stone that resonates with their personal style, budget, and the symbolic meanings they wish to carry.
History and Lore: A Legacy in Blue
Each of December's birthstones is steeped in a rich and varied history, with stories that span continents and millennia, from ancient civilizations to modern royalty.
Turquoise: The Ancient Talisman Turquoise is arguably the oldest and most historically significant of the December stones. This semi-translucent to opaque gem, ranging from sky blue to greenish hues and often traversed by distinctive veins of matrix (the remnant rock in which it formed), has been cherished for thousands of years. The pharaohs and other rulers of ancient Egypt adorned themselves with turquoise jewelry, and Chinese artisans were carving it into intricate objects more than 3,000 years ago. Its name derives from its journey to Europe through the gem markets of Turkey, after being mined in Persia and along the Sinai Peninsula. Historically, turquoise was regarded as a powerful protective amulet. From the 13th century onward, it was believed to safeguard the wearer from falls, particularly from horses, and was thought to shatter in the face of impending disaster. Hindu mystics believed that gazing upon a turquoise after seeing the new moon would bring fantastic wealth. The stone was also deeply embedded in the cultures of the American Southwest; the Apache believed turquoise could be found by following a rainbow to its end, and it was associated with youth and strength by Native American tribes. For the Tibetans, turquoise was a stone of fortune, health, and success, so valuable it was often used as currency.
Zircon: The Gem of Clarity Zircon, a gem known for its exceptional brilliance and fire, has a history that is often confused due to its similarity in name to the man-made cubic zirconia, a completely different material. Natural zircon is one of the oldest minerals on Earth, and its use as a gem dates back centuries. It was added to the official birthstone list in 1952, bringing its unique properties to the December family. Historically, zircon was believed to possess powers of wisdom, honor, and clarity. It was often associated with mental acuity and was thought to help its wearer see things clearly, both literally and metaphorically. Its high refractive index and strong dispersion give it a sparkle that rivals diamond, making it a prized gem for those seeking brilliance.
Tanzanite: The Modern Marvel Of all the December stones, tanzanite is the most recent addition, officially recognized in 2002. Its story is one of modern discovery and rapid ascent to fame. Found in only one location in the world—the Merelani Hills of northern Tanzania—this gem is exceptionally rare. Its discovery in the 1960s and subsequent marketing by Tiffany & Co. brought its captivating violet-blue hue to the world's attention. Tanzanite is often associated with transformation, new beginnings, and a sense of clarity and curiosity. Its color-shifting properties, from blue to violet depending on the light and viewing angle, are seen as a metaphor for stepping into new chapters of life. Its rarity and unique beauty have made it a favorite among celebrities, with notable figures like Beyoncé receiving tanzanite jewelry as gifts.
Blue Topaz: The Durable Classic Blue topaz has a more obscure historical origin but has become a staple in modern jewelry due to its durability and beautiful blue color. It is the official state gem of Texas, and while its exact historical use is less documented than the other December stones, it has been found throughout history. Today, it is mined in several countries, including Sri Lanka, Brazil, Mexico, Nigeria, and the U.S. Its addition to the December list provides a highly durable and often more affordable blue gem option.
Geological Formation and Global Sources
The origins of these four gems are as diverse as their histories, with each stone forming under unique geological conditions and being sourced from specific regions of the world.
Turquoise is a hydrated phosphate of copper and aluminum that forms in arid regions where acidic, copper-rich groundwater seeps through pre-existing rock. This process, known as secondary deposition, occurs over millions of years, depositing turquoise in veins and nodules within host rock. Major sources include the United States (particularly Arizona and New Mexico), Iran, China, and Egypt. The presence of the host rock matrix, often seen as a black or brown webbing within the stone, is a key identifier of its natural formation.
Zircon is a zirconium silicate that crystallizes from magma as an original mineral in igneous rocks like granite and syenite. It is a very durable mineral that can survive geological processes and is often found in alluvial deposits (sediments moved by water). It is mined in countries such as Cambodia, Sri Lanka, Thailand, and Australia.
Tanzanite is a variety of the mineral zoisite and owes its unique blue-violet color to trace amounts of vanadium. It formed around 585 million years ago when a massive geological event, likely a tectonic plate shift, subjected the zoisite crystals to intense heat and pressure, changing their chemical composition. This specific geological event occurred in a very small area of the Merelani Hills in Tanzania, which is the world's only source for this gem, making it thousands of times rarer than diamond.
Blue Topaz is a silicate mineral of aluminum and fluorine that forms in igneous and metamorphic rocks. The most desirable rich blue color seen in jewelry is typically the result of irradiation treatment applied to pale or colorless natural topaz. Major mining locations include Brazil, Mexico, Sri Lanka, and Nigeria.
Gemological Properties: A Scientific Overview
Understanding the physical and chemical properties of each gem is crucial for selecting the right piece of jewelry and ensuring its longevity. Durability is a key factor, primarily determined by hardness (on the Mohs scale) and toughness (resistance to breakage).
| Gemstone | Chemical Composition | Mohs Hardness | Crystal System | Key Characteristics |
|---|---|---|---|---|
| Tanzanite | Ca₂Al₃(SiO₄)₃(OH) | 6 - 6.5 | Orthorhombic | Trichroic (shows blue, violet, and reddish hues); often heat-treated to enhance color. |
| Turquoise | CuAl₆(PO₄)₄(OH)₈·4H₂O | 5 - 6 | Triclinic | Opaque to semi-translucent; color ranges from blue to green; often contains matrix. |
| Zircon | ZrSiO₄ | 6.5 - 7.5 | Tetragonal | High refractive index and strong dispersion ("fire"); can be heat-treated to produce blue. |
| Blue Topaz | Al₂SiO₄(F,OH)₂ | 8 | Orthorhombic | Excellent hardness and durability; color is often from irradiation treatment. |
Turquoise has a hardness of 5 to 6 on the Mohs scale. While it is relatively durable, it is a porous gem and can be susceptible to damage from chemicals, heat, and even prolonged exposure to skin oils and lotions, which can alter its color over time. It is often stabilized (treated with resin) to improve its durability and color retention.
Zircon is harder than the other December stones, with a Mohs hardness of 6.5 to 7.5, making it reasonably durable for most jewelry applications. However, it has fair to good toughness but can be brittle, so it should be protected from hard blows, especially in settings like rings where it might be exposed to impact.
Tanzanite has a hardness of 6 to 6.5. While it is not as soft as turquoise, it is considered more fragile than many other popular gems. It also possesses perfect cleavage in one direction, meaning it can split if struck with sufficient force along that plane. This makes it a gem that requires careful setting and is often recommended for earrings or pendants rather than daily-wear rings.
Blue Topaz is the most durable of the group, with a Mohs hardness of 8. This exceptional hardness makes it highly resistant to scratching and ideal for everyday-wear jewelry, such as engagement rings. Its toughness is generally good, and its stability is excellent, making it a low-maintenance and resilient choice.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, gemstones have been imbued with symbolic meaning and metaphysical properties. Each of December's stones carries a distinct set of beliefs and associations.
Turquoise is widely regarded as a stone of protection, grounding, and good fortune. It is seen as a steadying force, offering a sense of calm and tranquility. It is believed to warn its wearer of approaching illness or danger by changing color or becoming pale. For lovers and married couples, it was prized as a gem that could protect relationships and preserve friendship if given as a gift.
Tanzanite is a stone of transformation, spiritual awakening, and new beginnings. Its unique color-shifting nature is thought to stimulate the imagination and intuition, encouraging a higher consciousness and a fresh perspective on life. It is associated with clarity of thought and purpose.
Zircon is associated with clarity, wisdom, and balance. It is believed to sharpen the mind, boost mental acuity, and help its wearer see things with greater clarity and focus. It is also linked to honor and prosperity.
Blue Topaz is often associated with calm, serenity, and communication. It is believed to promote honest and clear communication, soothe tempers, and bring peace and relaxation to its wearer.
Care and Cleaning: Preserving Your Gem
Proper care is essential to maintain the beauty and integrity of any gemstone. Given their varying levels of hardness and toughness, the cleaning and storage recommendations for December's birthstones differ.
Turquoise: Due to its porosity and sensitivity, turquoise should be cleaned gently with warm, soapy water and a soft cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals. Store it separately to prevent scratching by harder gems.
Tanzanite: Clean with warm, soapy water and a soft brush. Avoid ultrasonic and steam cleaners, as the heat and vibrations can cause damage. Due to its perfect cleavage, protect it from sharp blows and temperature shocks.
Zircon: While fairly hard, zircon can be brittle. It is safe to use warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe, but steam cleaning is not recommended due to potential temperature changes that could cause fractures. Store it carefully to avoid chipping.
Blue Topaz: As the most durable of the group, blue topaz can be cleaned with warm, soapy water, a soft brush, and is also safe for ultrasonic cleaning. However, it is best to avoid sudden, extreme temperature changes, which could potentially cause fracturing.
Conclusion
December's birthstones offer a remarkable and unparalleled choice for those born in the final month of the year. From the ancient, protective talisman of Turquoise to the brilliant fire of Zircon, the transformative rarity of Tanzanite, and the durable elegance of Blue Topaz, each gem presents a unique combination of beauty, history, and meaning. Their shared palette of blue reflects the winter season, yet their individual stories and properties ensure there is a perfect stone for every taste and occasion. By understanding their distinct origins, gemological characteristics, and cultural significance, one can fully appreciate the rich and diverse treasure chest that is the December birthstone collection.