December, the final month of the year, is symbolized by a rich array of birthstones, each carrying its own unique history, symbolism, and gemological properties. Among these, tanzanite holds a special place—not only as a December birthstone but also as a relatively modern discovery that has captivated the world of gemology since its introduction in the 1960s. Officially added to the birthstone list in 2002, tanzanite is a vibrant blue to violet gem that is exclusively found in a small region of Tanzania. Its journey from a local discovery to an international treasure is as fascinating as its mesmerizing color.
This article delves into the history, geology, symbolism, and care of tanzanite, providing a comprehensive overview for gemstone enthusiasts, jewelry buyers, and students of gemology. Drawing from authoritative and historical sources, we explore the unique characteristics that make tanzanite a standout gemstone and a meaningful choice for those born in December.
History and Lore
Tanzanite’s discovery is a tale of serendipity and vision. In 1967, Maasai tribesmen in the foothills of Mount Kilimanjaro, Tanzania, stumbled upon a patch of striking bluish-violet crystals. These stones, initially mistaken for sapphires, were brought to a prospector named Manuel d’Souza, who shared them with prominent gemologists. It was soon revealed that these were not sapphires but a new and previously unknown variety of the mineral zoisite.
The discovery of tanzanite marked a pivotal moment in gemological history. Unlike most gemstones, which have been known and used for centuries, tanzanite is a modern find. Its vivid colors and unique properties quickly captured the attention of jewelers and collectors. In 1969, the gemstone was officially named tanzanite in honor of its country of origin, Tanzania, and it was marketed by Tiffany & Co., which played a significant role in bringing tanzanite into the global spotlight.
Tanzanite's addition to the December birthstone list in 2002 was a notable event, as it marked the first update to the birthstone list since 1912. This addition reflected the growing recognition of tanzanite's beauty and significance in the world of jewelry. The Smithsonian Institution further highlighted tanzanite's importance when it acquired an 18.56-carat emerald-cut tanzanite in 2011, purchased with funds from the Tiffany & Co. Foundation. This acquisition underscored tanzanite's status as a gemstone of both scientific and aesthetic value.
Geological Formation and Sources
Tanzanite is a variety of the mineral zoisite, a calcium aluminum hydroxyl sorosilicate. Its striking blue and violet hues are due to trace amounts of vanadium, which are present in the crystal structure. What makes tanzanite particularly unique is its trichroism—the property of displaying three different colors depending on the angle from which it is viewed. These colors typically include blue, violet, and burgundy, giving the stone a dynamic and ever-changing appearance.
The formation of tanzanite is tied to specific geological conditions. It is found only in a small area near the Mererani Hills in Tanzania, within a mining region that measures approximately 7 km (4.3 mi) long and 2 km (1.2 mi) wide. This limited geographic distribution makes tanzanite one of the rarest gemstones in the world. The crystals are typically found in metamorphic rocks formed by the transformation of pre-existing minerals under high pressure and temperature conditions.
In its natural state, tanzanite often appears reddish-brown or clear. To reveal its characteristic blue and violet colors, the stone must undergo heat treatment. This process removes the brownish “veil” that covers the crystal, allowing the vibrant blue and violet tones to emerge. The heat treatment is essential for enhancing the gemstone’s visual appeal and is a standard practice in the industry.
Gemological Properties
Tanzanite’s gemological properties are as impressive as its appearance. Here is a detailed overview of its key characteristics:
- Chemical Formula: Ca₂Al₃(SiO₄)(Si₂O₇)O(OH)
- Color: Blue to violet, with trichroism
- Hardness: 6–7 on the Mohs scale
- Refractive Index: 1.694–1.701
- Specific Gravity: 3.33–3.35
- Luster: Vitreous
- Transparency: Transparent to translucent
- Cut: Common cuts include emerald, oval, and cushion
- Cleavage: Perfect in one direction
Tanzanite’s hardness of 6–7 on the Mohs scale means that it is relatively durable but still requires careful handling to avoid scratches and fractures. Its refractive index contributes to its brilliance and sparkle, making it a popular choice for jewelry. The perfect cleavage in one direction necessitates careful cutting and setting to prevent damage.
The stone’s trichroism is a fascinating optical property. Depending on the orientation of the crystal and the type of lighting, tanzanite can appear blue, violet, or burgundy. This effect is particularly noticeable under different lighting conditions, with blues becoming more prominent under fluorescent light and violets standing out under incandescent illumination. This dynamic color change adds to tanzanite’s allure and makes it a captivating gemstone to observe.
Symbolism and Metaphysical Beliefs
Tanzanite is not only valued for its physical beauty but also for its symbolic and metaphysical properties. In the realm of gemstone symbolism, tanzanite is associated with transformation, intuition, and emotional healing. It is believed to promote self-awareness and spiritual growth, helping individuals navigate life's changes with grace and clarity.
The gemstone is also thought to have protective qualities. In some cultures, tanzanite is used to shield the wearer from negative energies and to foster a sense of calm and balance. Its connection to the color blue is often linked to serenity and peace, while the violet tones are associated with creativity and imagination.
In the context of birthstones, tanzanite symbolizes the transition and renewal associated with the end of the year. Its December birthstone status aligns with themes of reflection, celebration, and the promise of new beginnings. This makes tanzanite a meaningful choice for those born in December, as it resonates with the month's themes of change and hope.
Care and Cleaning
Given its gemological properties, proper care is essential to maintain tanzanite’s beauty and longevity. Here are some guidelines for cleaning and preserving tanzanite jewelry:
- Cleaning: Tanzanite can be cleaned with warm, soapy water and a soft brush. Ultrasonic and steam cleaners are generally safe, but it is advisable to avoid using these methods on jewelry with delicate settings or other sensitive gemstones.
- Storage: To prevent scratches and damage, store tanzanite separately from harder gemstones such as diamonds, rubies, and sapphires. A soft cloth or jewelry box with individual compartments is ideal.
- Wearing: Tanzanite should be worn with care to avoid exposure to hard surfaces that could cause scratches or chips. It is also important to remove tanzanite jewelry before engaging in activities that involve physical contact or abrasion.
- Professional Maintenance: Periodic inspections by a professional jeweler can help identify any loose settings or signs of wear, ensuring the gemstone remains secure and in good condition.
By following these care tips, tanzanite jewelry can retain its luster and beauty for many years, making it a cherished heirloom that can be passed down through generations.
Conclusion
Tanzanite is a gemstone of extraordinary beauty and significance. From its unique geological formation and limited geographic origin to its vibrant colors and symbolic meanings, tanzanite embodies the essence of December. Its journey from a local discovery in Tanzania to an international treasure reflects its enduring appeal and the value it holds in the world of gemology.
As a December birthstone, tanzanite represents the themes of transformation, renewal, and reflection. Its trichroism and dynamic color change make it a captivating gemstone that continues to inspire and enchant. Whether worn as a piece of jewelry or displayed as a collector’s item, tanzanite is a testament to the wonder of nature and the artistry of gemstone craftsmanship.
For those born in December, tanzanite is more than just a gemstone—it is a symbol of their birth month’s spirit and the magic that comes with the end of the year. Its rarity and beauty make it a meaningful and lasting gift, connecting the wearer to the history, culture, and science of one of the most fascinating gemstones in the world.