The tradition of birthstones offers a unique lens through which to view history, geology, and human culture, with each month presenting its own distinct treasures. For those born in December, the selection is particularly rich and varied. While many months are assigned a single gem, December boasts four officially recognized birthstones: Tanzanite, Zircon, Topaz, and Turquoise. This abundance provides a palette of cool, wintry blues that reflect the season's serene and crisp character. Among these, Tanzanite stands out as a modern marvel, a gemstone whose discovery in the 20th century captivated the world with its singular beauty and remarkable origin story. This article will provide a comprehensive exploration of Tanzanite, detailing its geological formation, gemological properties, historical significance, and the symbolic meanings that have made it a celebrated choice for those born in the final month of the year.
A Modern Marvel: The History and Discovery of Tanzanite
Unlike many gemstones whose origins are lost to antiquity, the story of Tanzanite is remarkably recent and well-documented. The gemstone was discovered in 1967 in the Merelani Hills of northern Tanzania, a region situated near the majestic Mount Kilimanjaro. This singular source location makes Tanzanite one of the most geographically rare gemstones known to humanity. The initial discovery is credited to a Tanzanian tailor named Manuel d'Souza, who found translucent blue crystals in his machете-cleared field. Initially, the stones were thought to be another form of zircon, but their unique properties and vibrant color quickly signaled that something entirely new had been unearthed.
The journey from a local discovery to a globally recognized gemstone was significantly propelled by the efforts of the international jewelry company Tiffany & Co. Recognizing the stone's extraordinary potential, Tiffany & Co. introduced Tanzanite to the world in 1968, heavily promoting it as "the most beautiful blue gem to be discovered in 2,000 years." They named the gemstone "Tanzanite" after its country of origin, a marketing masterstroke that cemented its identity and allure. The gem's rapid rise in popularity was also supported by the Maasai people of Tanzania, who associated its vibrant blue color with life and new beginnings, further enriching its cultural narrative.
The official recognition of Tanzanite as a birthstone was a more recent development. The modern list of birthstones, standardized by the National Association of Jewelers in 1912, did not include Tanzanite due to its nonexistence at the time. However, as the gem’s popularity and commercial appeal grew, the list was updated. In 2002, the American Gem Trade Association (AGTA) officially added Tanzanite to the list of birthstones for December, granting it a place alongside the traditional stones. This addition highlights the dynamic nature of birthstone traditions, which can evolve to incorporate new and significant gemological discoveries.
Geological Formation and Exclusive Origins
The genesis of Tanzanite is as unique as its color. It belongs to the mineral group known as zoisite, specifically the blue to violet variety. The formation of these gem-quality crystals is the result of a remarkable geological event that occurred approximately 585 million years ago during the Precambrian era. An intense tectonic shift, involving the collision of continental plates, subjected the rocks in the Merelani region to immense heat and pressure. This event metamorphosed the existing rocks, causing the mineral tremolite to transform into the vibrant blue zoisite we know as Tanzanite.
A crucial element in this transformation was the presence of vanadium, an element that permeated the crystals during the metamorphic process. It is the vanadium impurities within the crystal lattice that are responsible for Tanzanite's signature blue and violet hues. In some cases, the crystals also contain traces of chromium, which can enhance the violet tones. The conditions that created Tanzanite were extraordinarily specific, confining the gemstone to a tiny, four-square-kilometer mining area in the Merelani Hills. This extreme rarity is a primary factor in its high value and desirability. Unlike diamonds or sapphires, which are mined in various locations worldwide, a true, natural Tanzanite can only come from this one small area of Tanzania, making it at least a thousand times rarer than diamond, according to some estimates.
Gemological Properties: The Science of Beauty
Tanzanite is prized not only for its color but also for its distinct gemological characteristics. Understanding these properties is essential for gemologists, jewelers, and consumers alike.
Color: The most celebrated attribute of Tanzanite is its mesmerizing color. It exhibits a pleochroic property, meaning it can display different colors when viewed from different crystallographic directions. Typically, Tanzanite shows a deep blue along one axis and a violet-purple hue along another. This phenomenon is most effectively showcased when the gemstone is cut with the table facet perpendicular to the crystal's c-axis, allowing the dominant blue color to be viewed face-up. While the finest stones are a pure, intense blue, many are heat-treated to achieve this desirable color and reduce the presence of less valuable brownish hues.
Hardness and Durability: On the Mohs scale of mineral hardness, Tanzanite registers between 6 and 7. This places it in the moderately durable category, suitable for jewelry that is worn with care. However, its hardness is coupled with what gemologists call "perfect cleavage" along one direction. Cleavage is the tendency of a mineral to break along flat planes of weakness in its crystal structure. This means Tanzanite is more susceptible to chipping or breaking if struck with force. Consequently, it is not the ideal gemstone for everyday-wear rings that are prone to impact, such as an engagement ring. It is better suited for pendants, earrings, and occasion rings where the risk of damage is lower.
Clarity and Cut: Tanzanite is typically a "type II" gemstone in the GIA's clarity grading system, meaning it is usually found with some minor inclusions, though eye-clean stones are common. The cut of a Tanzanite is critical to maximizing its color. As a strongly pleochroic stone, the orientation of the crystal during the cutting process is paramount to achieving the most desirable face-up color. Master cutters must carefully orient the rough stone to showcase the best blue, often sacrificing more carat weight to achieve the perfect hue.
Treatment: The vast majority of Tanzanite on the market has been heat-treated. In its natural state, much of the rough material exhibits a brownish color. Heating the stones to temperatures of around 600 degrees Celsius (1100 degrees Fahrenheit) for a short period permanently removes the brownish overtones, resulting in the stable and vibrant blue-violet color that is commercially desired. This treatment is widely accepted in the gem trade and is considered permanent, with no risk of the color fading over time.
Symbolism and Metaphysical Beliefs
Throughout history, gemstones have been imbued with symbolic meaning and metaphysical properties, and Tanzanite is no exception. Despite its youth in the gemological world, it has quickly accumulated a rich tapestry of attributed powers and meanings.
Tanzanite is often referred to as the "stone of transformation." It is believed to facilitate a higher consciousness, intuition, and spiritual perception. Many crystal healers and enthusiasts associate Tanzanite with the throat and crown chakras, suggesting it can aid in clear communication and a deeper connection to the divine. Its calming energy is thought to be particularly effective for relieving stress, anxiety, and feelings of overwhelm, promoting a sense of tranquility and mindfulness.
The Maasai people, native to the region where Tanzanite is found, hold the stone in high regard, associating its brilliant blue color with new life and a promise of a prosperous future. It is often given as a token to celebrate significant life changes and milestones. For those born in December, Tanzanite is said to encourage personal growth, clarity of purpose, and the courage to embrace new beginnings, making it a powerful and meaningful birthstone.
Comparison with Other December Birthstones
To fully appreciate Tanzanite's place among December's gems, it is helpful to compare it with its counterparts: Turquoise, Zircon, and Topaz.
Turquoise: One of the oldest known gemstones, Turquoise is an opaque phosphate mineral that ranges in color from sky blue to greenish-blue. It is much softer than Tanzanite, with a Mohs hardness of 5 to 6. Its historical significance is immense, revered for centuries as a protective talisman. Unlike the crystalline clarity of Tanzanite, Turquoise is prized for its unique, often matrix-veined patterns.
Zircon: Not to be confused with the synthetic cubic zirconia, natural Zircon is a brilliant, lustrous gemstone with a high refractive index that rivals that of a diamond. Blue Zircon, the variety associated with December, is typically heat-treated from brownish zircon to achieve its color. It is relatively durable, with a Mohs hardness of 6.5 to 7.5, but can be brittle.
Blue Topaz: Blue Topaz is known for its transparency and excellent hardness of 8 on the Mohs scale, making it the most durable of the December stones for everyday wear. Its color, ranging from sky blue to deep Swiss or London blue, is almost always the result of irradiation and heat treatment of colorless topaz. It offers a more affordable and highly durable alternative.
Tanzanite distinguishes itself with its unique violet-blue hue, its extreme rarity from a single source, and its pleochroic nature. While it requires more care than Topaz or Zircon, its singular beauty and captivating color play are unmatched.
Care and Cleaning Recommendations
Given its gemological properties, proper care is essential to maintain the beauty and integrity of Tanzanite jewelry. Its moderate hardness and perfect cleavage make it susceptible to damage from sharp blows and abrasive materials.
Cleaning: The safest method for cleaning Tanzanite is with warm, soapy water and a soft brush. Gently scrub the gemstone and its setting, then rinse thoroughly with clean water to remove any soap residue. It is crucial to avoid ultrasonic cleaners and steam cleaners. The vibrations from an ultrasonic cleaner can cause existing fractures or cleavage planes to separate, potentially destroying the stone. Steam cleaning is also risky due to the potential for thermal shock.
Storage: To prevent scratching, Tanzanite should be stored separately from other jewelry pieces, ideally in a soft-lined box or a fabric pouch. Because of its cleavage, it should never be subjected to hard knocks or pressure. When not being worn, it is best to keep it protected and away from areas where it could be accidentally dropped or impacted. Removing Tanzanite rings before engaging in activities like gardening, sports, or heavy household chores is a wise precaution.
Conclusion
Tanzanite represents a remarkable chapter in the story of gemstones. It is a testament to the earth's capacity for creating singular beauty under extraordinary circumstances. From its recent discovery in the foothills of Mount Kilimanjaro to its rapid ascent as a globally cherished gem, Tanzanite's journey is as compelling as its mesmerizing color. As the modern birthstone for December, it offers those born in this month a symbol of uniqueness, transformation, and profound beauty. Its combination of intense color, geological rarity, and fascinating properties ensures its place as a modern classic, a true treasure from a single point on the globe that will continue to enchant generations of gemstone lovers, jewelers, and collectors.