The arrival of December marks the final chapter of the year, a time often associated with reflection, celebration, and the stark beauty of winter. For those born in this cold month, the birthstone tradition offers a unique distinction: December is the only month officially associated with three distinct gemstones. While many months have seen their birthstone lists evolve, December stands apart with a trio of blue-hued treasures—Turquoise, Tanzanite, and Blue Zircon—each possessing a unique geological origin, a rich tapestry of history, and a distinct set of gemological properties. These stones, all celebrated for their captivating shades of blue, mirror the cool, wintry palette of the season, from the icy sparkle of a zircon to the deep twilight of a tanzanite and the earthy sky-blue of a turquoise.
This comprehensive guide delves into the history, science, and symbolism of December's three official birthstones. We will explore the ancient lineage of Turquoise, the modern discovery of Tanzanite, and the often-misunderstood brilliance of Blue Zircon. For the gemstone enthusiast, the prospective jewelry buyer, and the student of gemology, understanding the distinct characteristics of each stone is key to appreciating the full spectrum of beauty and significance that December offers.
History and Lore: A Journey Through Time
The tradition of assigning gemstones to specific months has roots stretching back to ancient civilizations, but the modern list of birthstones is largely derived from a 1912 standard established by the National Association of Jewelers in the United States. This list has been updated over the years, reflecting both new discoveries and a desire to offer more variety. December's collection is a prime example of this evolution.
The Ancient Heritage of Turquoise
Turquoise is the traditional bedrock of December's birthstone trio, with a history that spans millennia and continents. Its very name hints at its storied journey to the Western world. According to historical accounts, the name "Turquoise" is derived from the French phrase pierre turquoise, meaning "stone of Turkey." This nomenclature arose because the gem was first brought to Europe from Turkish bazaars, where it had been traded along ancient routes. However, the stone's origins lie far from Turkey, with some of the earliest and most celebrated sources located in the Persian Empire (modern-day Iran), which produced the highly prized "Persian turquoise" known for its intense, robin's egg blue color.
Across different cultures, Turquoise has been revered as a stone of protection, good fortune, and power. Ancient Egyptians adorned themselves with Turquoise jewelry, inlaid it into ceremonial objects, and buried it with their dead, believing it offered a connection to the afterlife. The nomadic peoples of Central Asia and the indigenous tribes of the American Southwest have also held Turquoise in sacred regard for centuries, viewing it as a living stone that could offer a direct link to the sky and water, essential elements for life in arid landscapes. Its reputation as a protective amulet is legendary, with beliefs that it could shatter to warn its owner of impending danger or change color to reflect the health of the wearer.
The Modern Revelation of Tanzanite
In stark contrast to Turquoise's ancient lineage, Tanzanite is a thoroughly modern gem, yet one that has rapidly secured its place in the pantheon of great gemstones. Its story begins in the mid-20th century in a single, small area of the world. Tanzanite was discovered in 1967 in the Merelani Hills of northern Tanzania, near the base of Mount Kilimanjaro. The gemologist who first identified the crystal, Manuel de Souza, initially believed he had found an olivine deposit, but its unique properties quickly revealed it to be something entirely new.
The stone was initially marketed by Tiffany & Co., which recognized its extraordinary beauty and the marketing potential of its exclusive origin. The company named it "Tanzanite" after its country of origin and promoted it heavily as "the most beautiful blue gemstone to be discovered in 2,000 years." Its official recognition as a December birthstone came much later, in 2002, when the American Gem Trade Association (AGTA) added it to the list. This addition reflects the growing appreciation for newly discovered gemstones and their cultural impact. Tanzanite's symbolism is often linked to transformation and new beginnings, a fitting narrative for a stone that has, in a mere few decades, captivated the global jewelry market.
The Versatile Appeal of Blue Zircon and Blue Topaz
Zircon is one of the oldest minerals on Earth, with zircon crystals found in Australia dating back over 4.4 billion years. However, its use as a December birthstone is more recent. Alongside Turquoise, it was one of the original stones assigned to the month. It is important to distinguish Zircon from the synthetic cubic zirconia, a common diamond simulant. Natural Zircon is a distinct and valuable gemstone in its own right.
Blue Zircon, in particular, has been prized for its brilliance and fire. During the Victorian era, it was a popular choice for jewelry, often appearing in rings and brooches. Its association with wisdom, clarity, and honor has contributed to its enduring appeal. In the 20th century, Blue Topaz was introduced as an alternative December birthstone, and its affordability and wide range of blue shades made it extremely popular. While Blue Topaz is not one of the three official stones in the primary sources, its commercial success has made it a common choice for those seeking a December gem, offering a crisp, clear blue that complements the other stones.
Geological Formation and Mining Locations
Each of December's birthstones has a unique origin story, not just in history but in geology. Their formation processes and limited mining locations contribute to their rarity, value, and character.
Turquoise: The Hydrous Copper Mineral
Turquoise is not a single mineral but a hydrous phosphate of copper and aluminum. Its formation is a geological rarity, occurring in arid regions where acidic, copper-rich groundwater seeps through and reacts with minerals containing aluminum and phosphorus in pre-existing rocks over millions of years. This process, known as secondary deposition, gradually forms the nodules and veins of opaque turquoise.
The color of turquoise is directly tied to its chemical composition. The presence of copper imparts the characteristic blue and green hues, while iron can shift the color towards greenish shades. The dark veins and web-like patterns often seen in turquoise are known as "matrix," which is remnants of the host rock (such as chert or limonite) in which the turquoise formed.
The primary sources of turquoise today are: * Iran (Persia): Historically the source of the finest "sky blue" turquoise, though production is now limited. * The Southwestern United States: States like Arizona, New Mexico, and Nevada are famous for their turquoise mines, including the legendary Sleeping Beauty, Kingman, and Turquoise Mountain mines, which produce stones with distinct color and matrix characteristics. * China: A major producer of turquoise, often treated to enhance color and stability. * Egypt, Mexico, and Afghanistan: Also significant historical and current sources.
Tanzanite: A Unique Geological Anomaly
Tanzanite's formation is an even more specific and localized event. It is a variety of the mineral zoisite and gets its blue-violet color from trace amounts of vanadium. Its creation required a unique set of geological circumstances that occurred only in a small, 4-kilometer-square area in the Merelani Hills of Tanzania. Approximately 585 million years ago, the intense heat of the East African Rift metamorphosed the original rocks, allowing the zoisite crystals to grow. The presence of vanadium in the surrounding rock provided the crucial element for the gem's signature color.
This incredibly localized source means that Tanzanite is, for all practical purposes, only found in this one location on Earth, making it truly a "gem of a single source." This geographic rarity is a major factor in its value and appeal. Mining is conducted on a small scale, and the future supply is a subject of ongoing discussion within the gemological community.
Blue Zircon: The High-Temperature Metamorphic Gem
Zircon is a mineral composed of zirconium silicate. While it can form in a variety of geological environments, including igneous and metamorphic rocks, the gem-quality crystals suitable for faceting are often found in alluvial deposits (riverbeds and coastal areas) where they have been eroded from their original host rock.
The vibrant blue color seen in most December birthstone zircons is almost always the result of a heat treatment process. Natural zircon crystals, which are typically brown, are heated to very high temperatures (around 900-1000°C). This process removes the brown coloration and can produce a range of stable blue hues, from pale to deep sky blue. The most significant sources for zircon include: * Cambodia: Known for producing high-quality blue zircon. * Sri Lanka: A traditional source for a wide variety of gemstones, including zircon. * Thailand, Australia, and Nigeria: Also notable producers.
Gemological Properties: A Comparative Analysis
Understanding the scientific characteristics of these gemstones is crucial for jewelers and consumers alike. Their hardness, stability, and optical properties dictate how they should be worn, set, and cared for. The following table provides a side-by-side comparison of the key gemological data for Turquoise, Tanzanite, and Blue Zircon, based on information from the provided sources.
| Property | Turquoise | Tanzanite | Blue Zircon |
|---|---|---|---|
| Mineral Species | Hydrous phosphate of copper & aluminum | Variety of Zoisite | Zirconium Silicate |
| Chemical Formula | CuAl₆(PO₄)₄(OH)₈·4H₂O | Ca₂Al₃(SiO₄)₃(OH) | ZrSiO₄ |
| Color | Opaque blue to green, often with matrix (brown/black veins) | Blue to violet-blue, pleochroic (shows blue and violet) | Typically light to dark blue (often treated) |
| Hardness (Mohs Scale) | 5 - 6 | 6.5 - 7 | 6.5 - 7.5 |
| Crystal System | Triclinic | Orthorhombic | Tetragonal |
| Lustre | Waxy to subvitreous | Vitreous (glass-like) | Adamantine (brilliant) to vitreous |
| Transparency | Opaque | Transparent to translucent | Transparent to translucent |
| Special Characteristics | Its color is derived from copper; matrix patterns are unique to each stone. | Strong pleochroism; often heated to enhance color. | High refractive index and brilliance; most commercial blue zircon is heat-treated. |
As the table illustrates, there is a significant difference in hardness between Turquoise and the other two stones. Turquoise, with a hardness of 5 to 6 on the Mohs scale, is considerably softer than Tanzanite (6.5-7) and Blue Zircon (6.5-7.5). This difference is a critical factor in determining the stone's suitability for different types of jewelry, particularly for items like rings and bracelets that are subject to daily wear and potential impact.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, each of December's stones carries a rich layer of symbolism and is believed by many to possess metaphysical properties.
Turquoise: Universally regarded as a stone of protection, healing, and good fortune. It is believed to act as a spiritual shield, warding off negative energy and promoting inner calm. Many cultures view it as a stone of communication, bridging the gap between the earthly and the spiritual realms. Its connection to the sky and water reinforces its symbolism of tranquility and wisdom.
Tanzanite: As a relatively new gem, its metaphysical lore is more modern but no less potent. It is associated with transformation, spiritual awakening, and a higher consciousness. Its unique blue-violet color is said to stimulate the throat and third-eye chakras, enhancing intuition and psychic abilities. It is often seen as a stone for those embarking on new life chapters, offering clarity and a sense of purpose.
Blue Zircon: This gem has long been associated with clarity of thought, wisdom, and honor. It is believed to help its wearer achieve a state of balance and spiritual grounding. Historically, it was also thought to promote prosperity and honor, making it a popular talisman for travelers and merchants. Its brilliant sparkle is said to represent purity and innocence.
Care and Cleaning: Preserving Your Gemstone
Given their differing physical properties, the care requirements for each of December's birthstones vary significantly.
Turquoise Care: Due to its relative softness and inherent porosity, Turquoise requires gentle handling. It is susceptible to scratching from harder materials and can be damaged by chemicals. * Cleaning: Use only warm, soapy water and a soft cloth. Avoid ultrasonic cleaners, steam cleaners, and harsh chemicals like bleach or ammonia. * Storage and Wear: Store it separately to prevent scratching. Put on turquoise jewelry after applying cosmetics, hairspray, and perfume. The stone can absorb oils and chemicals, which may lead to discoloration over time. Some turquoise is stabilized (treated with wax or resin) to improve its durability, but it still requires careful handling.
Tanzanite Care: Tanzanite has good hardness but possesses perfect cleavage in one direction, meaning it can be easily split or fractured by a sharp blow. This makes it a delicate gem, best suited for earrings and pendants rather than rings that might experience impact. * Cleaning: Warm, soapy water and a soft brush are safe. As with turquoise, avoid ultrasonic and steam cleaners, as the vibrations and heat can cause the stone to fracture. * Storage and Wear: Handle with care to avoid drops or impacts. Store it in a soft cloth or a separate compartment in a jewelry box.
Blue Zircon Care: Blue Zircon has a higher hardness and is more durable than the other two stones, but it can be brittle due to its crystal structure. It is also sensitive to sudden temperature changes. * Cleaning: Warm, soapy water and a soft brush are recommended. While it is generally safe in an ultrasonic cleaner for a short period, it is best to avoid one if the stone has any surface-reaching fractures. Steam cleaning is not recommended. * Storage and Wear: It is durable enough for most jewelry types, including rings, but care should still be taken to avoid hard knocks. Store it away from other gems that could scratch it.
Conclusion
December's birthstones offer a remarkable trifecta of history, science, and symbolism. From the ancient, protective legacy of Turquoise, carried from the bazaars of Turkey and the mines of Persia, to the singular, modern discovery of Tanzanite in the shadow of Mount Kilimanjaro, and the timeless, brilliant fire of Blue Zircon, each gem tells a unique story. Together, they form a collection perfectly suited to the month of December, embodying the cool, serene, and brilliant qualities of winter. For those born in this month, the choice is not merely one of color but of character—whether one is drawn to the earthy wisdom of Turquoise, the transformative energy of Tanzanite, or the clarifying brilliance of Blue Zircon. Each stone, a treasure of the Earth, provides a personal and enduring connection to the natural world and the rich traditions of the past.