The gemstone associated with the date December 27th, a date falling within the zodiac sign of Capricorn, is Tanzanite. This remarkable gem, a variety of the mineral zoisite, is celebrated for its striking violet-blue hue and its status as a relatively modern discovery. As a birthstone for December, and specifically linked to Capricorns born on this day, Tanzanite embodies themes of transformation, clarity, and grounding—qualities that resonate with the ambitious and disciplined nature of the Capricorn sign. This article delves into the historical journey, geological origins, gemological properties, and cultural significance of Tanzanite, providing a comprehensive overview for gemstone enthusiasts, jewelry buyers, and students of gemology.
History and Lore
Tanzanite’s history is remarkably brief compared to many other gemstones, which is a key part of its allure. The gem was first discovered in 1967 in the Merelani Hills of northern Tanzania, hence its name. This makes it one of the youngest gemstones to enter the commercial market on a global scale. Its rapid ascent to prominence is largely attributed to the international jewelry house Tiffany & Co., which recognized its potential and launched a major marketing campaign in 1968, positioning it as a "blue sensation" from Africa.
Prior to the 20th century, Tanzanite did not exist in the gemological record, meaning it has no ancient lore or historical use in royal regalia or ancient civilizations. Its symbolism is therefore entirely modern, shaped by its color, rarity, and the marketing narratives that have surrounded it. According to contemporary metaphysical beliefs, Tanzanite is associated with transformation, insight, and intuition. For Capricorns, it is said to offer grounding energy and emotional depth, helping to balance the sign’s often pragmatic and disciplined nature with greater emotional awareness.
The gem’s journey to becoming an official December birthstone was also a modern process. The American Gem Trade Association (AGTA) added Tanzanite to its list of official birthstones in 2002, joining Turquoise and Zircon as the three modern birthstones for December. This official recognition cemented its place in the jewelry industry and among consumers seeking meaningful gemstones.
Geological Formation and Sources
Tanzanite’s geological story is as unique as its color. It is a variety of zoisite, a mineral that belongs to the epidote group. The specific conditions required to produce the vibrant blue-violet color are extraordinarily rare. Tanzanite forms when zoisite is subjected to intense heat and pressure, a process that is believed to have occurred during the metamorphism of the surrounding rocks in the Merelani Hills. The source of this heat is thought to be related to the formation of the nearby Mount Kilimanjaro, though the exact geological events remain a subject of study.
The gem’s formation is also closely linked to the presence of vanadium, which is responsible for its distinctive color. The original zoisite is typically brownish, and the heat treatment (which is standard in the industry) is necessary to induce the blue and violet hues. This process is irreversible and is a key part of preparing Tanzanite for the market.
Geographically, Tanzanite’s occurrence is extremely limited. It is mined almost exclusively in a small, four-square-kilometer area in the Merelani Hills of Tanzania. This geographic concentration is a primary factor in its rarity and value. The mines are located at the base of Mount Kilimanjaro, and the gem is often found in association with other minerals like calcite and diopside. The limited mining area and the challenges of extraction contribute to its status as one of the rarest gemstones in the world.
Gemological Properties
Tanzanite possesses a unique set of gemological characteristics that define its identity and value. Understanding these properties is essential for anyone interested in purchasing, collecting, or studying this gem.
Color: The most defining feature of Tanzanite is its color, which ranges from a pure, vibrant blue to a deep violet. The gem exhibits strong trichroism, meaning it can display three different colors depending on the viewing angle: typically blue, violet, and a reddish-brown. This property makes the cut of the stone crucial, as a skilled cutter will orient the gem to showcase the most desirable blue-violet hue.
Hardness and Durability: On the Mohs scale of mineral hardness, Tanzanite rates between 6 and 7. While this makes it relatively durable for everyday wear in jewelry, it is softer than many other popular gemstones like sapphire (9) or diamond (10). Therefore, it requires careful handling to avoid scratches and impacts. It is not recommended for rings that will be subjected to frequent hard wear, such as an engagement ring, but it is well-suited for pendants, earrings, and occasional-wear rings.
Clarity: Tanzanite is typically a clean gemstone, with inclusions being less common than in many other colored stones. When inclusions are present, they are often fine needles or small crystals. The gem is usually faceted to enhance its brilliance and color, though cabochon cuts are also used, especially for stones with lower clarity or to highlight asterism (star effects), which is rare in Tanzanite.
Cut and Carat: As a relatively recent addition to the gem market, Tanzanite is cut in a wide variety of modern styles to maximize its color and brilliance. It is available in a broad range of carat sizes, from small accent stones to large, spectacular centerpieces. Larger stones are particularly prized due to the rarity of the material.
Chemical Composition: Tanzanite is a calcium aluminum hydroxyl silicate with the chemical formula Ca₂Al₃(SiO₄)₃(OH). The presence of vanadium as a trace element is responsible for its blue color.
The following table summarizes key gemological properties of Tanzanite:
| Property | Description |
|---|---|
| Mineral Species | Zoisite |
| Chemical Formula | Ca₂Al₃(SiO₄)₃(OH) |
| Color | Blue, violet-blue; strong trichroism (blue, violet, reddish-brown) |
| Hardness (Mohs) | 6 - 7 |
| Crystal System | Orthorhombic |
| Refractive Index | 1.691 - 1.700 |
| Specific Gravity | 3.35 |
| Luster | Vitreous (glass-like) |
| Transparency | Transparent to translucent |
| Origin | Merelani Hills, Tanzania (primary source) |
Symbolism and Metaphysical Beliefs
While lacking ancient lore, Tanzanite has accumulated a rich tapestry of modern metaphysical beliefs, many of which align with the characteristics of the Capricorn zodiac sign. As a birthstone for December, and specifically for those born on December 27th, it is associated with several key themes.
For Capricorns, who are often characterized as ambitious, disciplined, and grounded in the material world, Tanzanite is said to offer a bridge to higher consciousness and emotional depth. It is believed to enhance intuition and insight, helping Capricorns to make decisions that are not only logically sound but also aligned with their inner wisdom. This can be particularly valuable for individuals who are driven by goals and responsibilities, as it encourages a more holistic approach to success.
Metaphysically, Tanzanite is often linked to transformation. Its discovery in 1967 and its rapid rise to fame mirror a theme of sudden, profound change. For the wearer, it is thought to facilitate personal transformation, helping to release old patterns and embrace new ways of being. This aligns with the Capricorn’s capacity for strategic planning and long-term growth.
Furthermore, Tanzanite is associated with clarity and communication. Its vibrant color is reminiscent of the sky and the deep sea, symbolizing open communication and emotional honesty. It is believed to help the wearer express their thoughts and feelings with greater clarity and compassion, which can enhance both personal and professional relationships.
In the context of the December 27th birthstone, sources indicate that Tanzanite provides "grounding energy and emotional depth" for Capricorns born on this date. This suggests that while Capricorns are naturally grounded, Tanzanite can help them connect more deeply with their emotions and the spiritual aspects of their lives, balancing their earthly ambitions with inner peace.
Care and Cleaning
Due to its moderate hardness and lack of cleavage, Tanzanite requires careful maintenance to preserve its beauty and integrity. While it is durable enough for most types of jewelry, it is not as hard as some other gems, making proper care essential.
Cleaning: The safest method for cleaning Tanzanite is using warm water, a mild dish soap, and a soft brush. Ultrasonic cleaners and steam cleaners should be avoided, as the vibrations and heat can potentially damage the stone, especially if it has any fractures or inclusions. After cleaning, rinse thoroughly and dry with a soft, lint-free cloth.
Storage: When not worn, Tanzanite jewelry should be stored separately from other jewelry to prevent scratching. A soft pouch or a lined jewelry box is ideal. Given its relative softness, it is wise to remove Tanzanite rings before engaging in activities that could subject the stone to impact or abrasion, such as gardening, sports, or heavy manual work.
Avoiding Chemicals: Tanzanite should be protected from harsh chemicals, including household cleaners, cosmetics, and perfumes. These substances can dull the surface of the gem over time. It is advisable to put on Tanzanite jewelry after applying makeup and perfumes.
Professional Check-ups: For Tanzanite jewelry that is worn regularly, especially rings, it is recommended to have it inspected by a professional jeweler periodically. They can check the security of the setting and the condition of the stone, ensuring it remains safely mounted.
Conclusion
Tanzanite stands as a remarkable gemstone in the modern world of gems. Its journey from a recent discovery in 1967 to an official December birthstone and a symbol of Capricorn ambition is a testament to its unique beauty and cultural impact. For those born on December 27th, it offers a stone that is not only visually stunning but also rich with symbolic meaning, promoting transformation, clarity, and emotional grounding.
Its geological rarity, confined to a single valley in Tanzania, adds to its mystique and value. While its hardness requires mindful wear and care, its vibrant color and compelling story make it a cherished addition to any jewelry collection. As a gemstone that bridges the gap between the ancient earth and modern aspirations, Tanzanite continues to captivate collectors, jewelers, and enthusiasts worldwide, solidifying its place as a significant and meaningful birthstone for the Capricorn born in December.