For individuals born on December 17th, a unique and vibrant gemstone serves as their designated birthstone: Tanzanite. This relatively modern addition to the birthstone canon has rapidly ascended in prominence, captivating collectors and jewelry enthusiasts with its striking blue-violet hues and a geological history that spans mere decades. Unlike many ancient gemstones with centuries of lore, Tanzanite’s story is one of recent discovery and immediate cultural impact. It embodies a rare combination of aesthetic beauty, metaphysical symbolism, and a geographical source so limited that it is often described as one of the most precious gemstone discoveries of the 20th century.
This article explores the multifaceted nature of Tanzanite, delving into its historical emergence, the unique geological conditions that create it, its defining gemological properties, and the symbolic meanings attributed to it. By examining these aspects, we can understand why this gemstone, born from a specific moment in time and a single location on Earth, holds such a powerful significance for those born in its month.
The History and Lore of a Modern Gemstone
The history of Tanzanite is remarkably brief compared to that of other gemstones like sapphire or emerald. Its story begins not in antiquity but in the mid-20th century, marking a significant moment in the modern gemstone industry. According to gemological sources, Tanzanite was discovered in 1967 in the foothills of Mount Kilimanjaro in Tanzania, East Africa. This event introduced a new and mesmerizing option for December-born individuals, quickly establishing the gem as a coveted jewel.
The gemstone’s initial identification and naming are linked to the renowned jewelry company Tiffany & Co. After recognizing the potential of this newly found blue mineral, Tiffany & Co. introduced it to the global market in 1968, naming it "Tanzanite" in honor of its exclusive country of origin. This strategic marketing played a crucial role in elevating the gem’s profile, associating it with luxury and exclusivity from the outset.
Prior to its official discovery and naming, the material was known to local prospectors but was often mistaken for sapphire due to its blue coloration. However, its chemical composition and physical properties were distinct, revealing it to be a variety of the mineral zoisite. The discovery was particularly significant because it presented a new source of vivid blue gem material at a time when the market for sapphires was well-established but sources were often limited or politically complex. The rapid acceptance and popularity of Tanzanite demonstrate the gemstone industry’s capacity to embrace and elevate a new find when it possesses the right combination of beauty, rarity, and marketability.
Geological Formation and Exclusive Sources
The genesis of Tanzanite is as extraordinary as its appearance. It is a product of a rare and specific geological event: the metamorphism of the mineral zoisite. This process occurred approximately 585 million years ago during the formation of the Neoproterozoic Mozambique Belt, a massive geological structure that stretches across East Africa. The intense heat and pressure from tectonic activity caused the original zoisite crystals to recrystallize and incorporate trace elements, most notably vanadium, which is responsible for the stone’s characteristic blue and violet hues.
What makes Tanzanite’s formation even more remarkable is that it is believed to have occurred only once in geological history. The specific conditions required—precise temperature, pressure, and chemical environment—are thought to be unique to the Merelani Hills of northern Tanzania. This singular event confines the gemstone’s commercial source to a very small area of just a few square kilometers near the base of Mount Kilimanjaro. This extreme geographical limitation is the primary reason for its rarity and exclusivity. Unlike gemstones such as quartz or topaz that can be found in multiple locations worldwide, Tanzanite is, for all practical purposes, available from only one place on Earth.
The mining of Tanzanite is a significant economic activity in the region, with both large-scale commercial operations and small-scale artisanal miners contributing to the global supply. However, the finite nature of the deposit raises concerns about long-term availability, further enhancing the gem’s status as a rare and valuable resource. This singular source is a key factor in its identity and value proposition in the gem market.
Gemological Properties
Tanzanite is a member of the zoisite mineral group, specifically a variety colored by vanadium. Its properties make it a distinctive and desirable gemstone for jewelry, though they also require specific considerations for cutting and care.
Color: The most defining characteristic of Tanzanite is its color, which ranges from a pure, ultramarine blue to a vibrant violet, often with a secondary reddish or purple pleochroic flash. Pleochroism is a property where a gemstone displays different colors when viewed from different crystal directions. In Tanzanite, this manifests as a dramatic shift between blue, violet, and sometimes a reddish hue. This dynamic color play is highly valued and is a key factor in its visual appeal. The intensity of the blue hue is directly linked to the concentration of vanadium in the crystal structure.
Hardness and Durability: On the Mohs scale of mineral hardness, Tanzanite ranks between 6 and 7. This places it in the "fair to good" category for gemstone durability. While it is not as hard as topaz (Mohs 8) or corundum (sapphire/ruby, Mohs 9), it is harder than many other popular gemstones like opal (Mohs 5.5-6.5) or fluorite (Mohs 4). However, its hardness is coupled with a notable lack of toughness due to its crystal structure. Tanzanite has perfect cleavage in one direction, meaning it can be split cleanly along specific planes if struck with sufficient force. This makes the gemstone vulnerable to chipping or fracturing if knocked against hard surfaces. Consequently, it is best suited for jewelry settings that offer protection, such as bezel settings or pendants, rather than rings that are prone to daily impact.
Clarity and Inclusions: Tanzanite is typically a very clean gemstone. Most commercial-quality material is "eye-clean," meaning it has no inclusions visible to the naked eye. However, like most gemstones, it can contain natural inclusions. Common inclusions may include fine needles, fingerprints, or small crystals. The presence and type of inclusions can affect the stone's clarity grade and value, with cleaner stones commanding higher prices.
Cut: Due to its strong pleochroism, cutting Tanzanite requires skill and precision. Gem cutters must orient the crystal to display the most desirable color combination, typically emphasizing the rich blue and violet tones while minimizing any undesirable brownish or grayish hues. The most common cuts are oval, cushion, and emerald cuts, which help to maximize color saturation and minimize the appearance of cleavage planes.
Chemical Composition: The chemical formula for zoisite is Ca₂Al₃(SiO₄)₃(OH). The presence of vanadium (V) as a trace element is what causes the blue-violet coloration in Tanzanite. Heat treatment is a standard and widely accepted practice in the industry to enhance the color of Tanzanite. Most rough material as mined is brownish or yellowish and requires heating to temperatures between 350°C and 500°C to develop its signature blue and violet colors. This treatment is permanent and stable, and it is disclosed to consumers by reputable dealers.
| Property | Specification |
|---|---|
| Mineral Species | Zoisite (Variety: Tanzanite) |
| Chemical Formula | Ca₂Al₃(SiO₄)₃(OH) |
| Color | Blue, violet, with pleochroic flashes of red |
| Mohs Hardness | 6 – 7 |
| Crystal System | Orthorhombic |
| Refractive Index | 1.691 – 1.700 |
| Specific Gravity | 3.35 |
| Origin | Merelani Hills, Tanzania |
| Treatment | Heat (common and accepted) |
Symbolism and Metaphysical Beliefs
While its scientific properties are fascinating, the allure of Tanzanite is also deeply rooted in its symbolic and metaphysical meanings. As a modern birthstone, it has accumulated a rich layer of spiritual significance, often associated with traits that resonate with individuals born in December, particularly Sagittarius and Capricorn.
Spiritual Enlightenment and Intuition: One of the most prominent beliefs associated with Tanzanite is its connection to spiritual growth and enlightenment. Its deep, calming blue tones are said to encourage a connection with higher realms of consciousness and intuition. Practitioners believe that wearing or meditating with Tanzanite can open the mind to spiritual insights, enhance psychic abilities, and foster a deeper understanding of one's life purpose. It is often described as a stone of transformation, guiding the wearer through change with clarity and wisdom.
Emotional Balance and Calm: The vibrant yet soothing hues of Tanzanite are thought to have a harmonizing effect on emotions. It is believed to promote a sense of balance, tranquility, and peace, helping to alleviate stress, anxiety, and feelings of overwhelm. For individuals navigating complex emotional landscapes, Tanzanite is said to provide a stabilizing influence, encouraging grace, poise, and emotional resilience. It is often used to soothe grief and bring comfort during difficult times.
Communication and Self-Expression: Tanzanite’s association with the throat chakra aligns it with effective communication and authentic self-expression. It is believed to clear blockages in the throat chakra, enabling the wearer to articulate thoughts and feelings with greater clarity and confidence. This makes it a powerful stone for public speakers, teachers, and anyone who wishes to communicate more openly and honestly in personal and professional relationships. It is also associated with listening skills, promoting understanding and empathy in conversations.
A Gemstone for December Born: For those born on December 17th and throughout the month, Tanzanite is seen as a stone that amplifies the positive traits of their zodiac signs. For Sagittarians (November 22 – December 21), it can enhance their natural optimism, adventurous spirit, and philosophical mindset. For Capricorns (December 22 – January 19), it can support their discipline, ambition, and practicality while adding a touch of creativity and emotional depth. Overall, it is considered a stone of individuality and personal power, reflecting the unique qualities of each person born under its influence.
Care and Cleaning
Due to its specific gemological properties, particularly its cleavage and moderate hardness, Tanzanite requires careful handling and maintenance to preserve its beauty and integrity. Proper care ensures that the gemstone remains a lasting treasure.
Cleaning: The safest method for cleaning Tanzanite is with warm water, a mild dish soap, and a soft brush (such as a baby toothbrush). Gently scrub the stone and its setting, paying attention to the back where dirt can accumulate. Rinse thoroughly with clean water to remove any soap residue. It is crucial to avoid harsh chemicals, including household cleaners, bleach, and ammonia, as these can damage the stone or its setting. Ultrasonic cleaners and steam cleaners are generally not recommended for Tanzanite due to the risk of thermal shock or vibrations that could exploit its cleavage planes, potentially causing fractures.
Storage: When not being worn, Tanzanite jewelry should be stored separately from other pieces to prevent scratching. It is best placed in a soft-lined jewelry box or a fabric pouch. Given its cleavage, it should never be tossed loosely into a jewelry box where it can come into contact with harder gemstones like diamonds, sapphires, or rubies.
Wearing Considerations: While Tanzanite is beautiful in rings, earrings, and pendants, its use in rings should be approached with caution for daily wear. For a ring that will be worn frequently, a protective setting like a bezel or a halo of smaller, harder gemstones is advisable. Pendants and earrings are often safer choices as they are less likely to encounter hard impacts. It is also wise to remove Tanzanite jewelry before engaging in physical activities, gardening, or any task where the stone could be knocked or exposed to abrasive materials.
Conclusion
Tanzanite stands as a testament to the dynamic and ever-evolving world of gemstones. Its story—from a chance discovery in the foothills of Mount Kilimanjaro to its status as a cherished December birthstone—is a modern gemological narrative. The gemstone’s exclusive geographical source, its captivating blue-violet color enhanced by vanadium, and its unique physical properties make it a subject of both scientific interest and aesthetic admiration.
Beyond its physical attributes, Tanzanite has woven itself into a tapestry of symbolism, representing spiritual insight, emotional balance, and clear communication. For those born on December 17th, it offers more than just a beautiful adornment; it serves as a personal talisman, connecting them to a specific moment in geological and human history. Its rarity, both in formation and source, underscores its value, reminding us that true beauty often arises from unique and singular conditions. As a gemstone that has captured the world's attention in just a few decades, Tanzanite’s legacy continues to grow, promising to remain a significant and celebrated jewel for generations to come.