In the diverse landscape of birthstones, few possess the unique allure and modern mystique of the gemstone designated for those born on December 15th. While December is traditionally associated with a quartet of blue gemstones—Turquoise, Zircon, and Topaz—a specific inquiry into the birthstone for this precise date reveals a singular focus: Tanzanite. This rare gemstone, a relative newcomer to the world of fine jewelry, has captivated collectors and designers with its extraordinary violet-blue hue and compelling narrative.
For individuals born on December 15th, the birthstone is Tanzanite. This rare and stunning gemstone was discovered relatively recently, in 1967, in the Merelani Hills of Tanzania. It is renowned for its striking blue-violet hue, making it a favorite among gemstone enthusiasts and jewelry connoisseurs alike. This article provides a comprehensive examination of Tanzanite, exploring its geological origins, gemological properties, historical journey to becoming a birthstone, and the deep symbolism it holds. We will also address the practical aspects of caring for this unique gem, ensuring that it remains a cherished heirloom for generations to come.
History and Lore: A Modern Discovery with Ancient Allure
The history of Tanzanite is a compelling story of serendipity and rapid ascent in the gemological world. Unlike gemstones such as Diamond or Ruby, which have been prized for millennia, Tanzanite’s history is remarkably brief. It was discovered in 1967 in the Merelani Hills of Northern Tanzania, near the base of Mount Kilimanjaro. The gem was initially identified by a Tanzanian prospector named Manuel d’Souza, who quickly realized he had found something significant. Initially, the gem was thought to be another form of Zircon, but further analysis confirmed it was a distinct mineral species, a variety of Zoisite.
The gemstone’s rise to prominence was significantly aided by the marketing efforts of the jewelry company Tiffany & Co., which recognized its potential and named it "Tanzanite" after its country of origin. Tiffany heavily promoted the gem as a rare, one-time find, a narrative that continues to contribute to its value and desirability today.
Regarding its status as a birthstone, the sources indicate a timeline of official recognition. In 1912, the National Association of Jewelers standardized the unofficial American birthstones. This list evolved over time. In 1952, the Jewelry Industry Council of America updated the list, adding Zircon to December’s list. Tanzanite was added much later, in 2002, solidifying its place as a modern birthstone for the month of December. Its addition reflects the dynamic nature of birthstone lists, which can evolve with new gemstone discoveries and commercial offerings.
While its official recognition is modern, the lore surrounding Tanzanite is potent. Many believe that Tanzanite is a stone of transformation and spiritual growth. Its deep blue color is thought to represent the vastness of the sky, symbolizing the infinite possibilities and opportunities that life holds. This metaphysical significance has made it a meaningful and thoughtful gift, particularly for those marking significant life changes or milestones.
Geological Formation and Sources
Tanzanite’s geological story is as unique as its color. It is a variety of the mineral Zoisite, and its formation requires a specific and rare set of geological circumstances. The gem is found exclusively in a small, four-square-kilometer area in the Merelani Hills of Tanzania. This singular source location is the primary reason for its rarity.
The formation of Tanzanite is believed to be the result of a unique geological event. Roughly 585 million years ago, tectonic plate movement caused intense heat and pressure, which altered the chemical composition of the host rock, transforming the original blue Zoisite into the vibrant gemstone we know today. This process, known as metamorphism, created the conditions necessary for Tanzanite crystals to grow.
The mining of Tanzanite is concentrated in the Merelani Hills. The area is divided into four blocks, with Block C being the most productive. The mining operations range from large-scale commercial ventures to smaller, artisanal diggings. The rarity of the gem is underscored by the fact that, despite extensive exploration, no other deposits of commercial quality have been found anywhere else in the world. This exclusivity is a key factor in its market value and desirability.
Gemological Properties
Tanzanite possesses a unique set of gemological characteristics that distinguish it from other blue gemstones. Its most defining feature is its color, but other properties such as hardness, clarity, and refractive index are also critical to understanding its value and wearability.
Color: The most celebrated attribute of Tanzanite is its vivid blue-violet hue. The gem exhibits strong trichroism, meaning it can display three different colors when viewed from different crystallographic directions: blue, violet, and a reddish-purple. The most desirable color is a deep, saturated blue with a distinct violet overtone. The violet component is often so pronounced that the gem is described as having a "violet-blue" or "blue-violet" color.
Hardness and Durability: On the Mohs scale of hardness, Tanzanite is rated at approximately 6 to 7. This places it in the moderate range for gemstones. While it is suitable for jewelry, it is not as hard as Sapphire (Mohs 9) or Diamond (Mohs 10). Consequently, it is more susceptible to scratching and abrasion and should be handled with care. It also possesses perfect cleavage in one direction, meaning it can split if struck with sufficient force along that plane. This makes it a less durable choice for rings that will be worn daily, such as engagement rings or everyday hand jewelry.
Clarity: Tanzanite is typically a "type I" gemstone, meaning it is usually inclusion-free or has very minor inclusions. High-quality Tanzanite is characterized by its exceptional clarity and transparency. Any visible inclusions can significantly reduce the stone's value.
Chemical Composition: Tanzanite is a calcium aluminum hydroxyl sorosilicate. Its chemical formula is Ca2Al3(SiO4)3(OH). It belongs to the Zoisite mineral group.
Other Properties: Tanzanite has a refractive index of 1.691 to 1.700 and a specific gravity of 3.35. It is pleochroic, displaying different colors when viewed from different angles.
Summary of Gemological Properties
| Property | Description |
|---|---|
| Mineral | Zoisite (Calcium Aluminum Hydroxyl Sorosilicate) |
| Hardness (Mohs) | 6 - 7 |
| Refractive Index | 1.691 - 1.700 |
| Specific Gravity | 3.35 |
| Cleavage | Perfect in one direction |
| Origin | Merelani Hills, Tanzania (exclusive) |
| Typical Color | Blue-Violet (strongly trichroic) |
Symbolism and Metaphysical Beliefs
Beyond its physical beauty, Tanzanite is steeped in symbolism and metaphysical beliefs. Its relatively recent discovery has not prevented it from acquiring a rich layer of lore, much of which is tied to its perceived powers of transformation and spiritual awareness.
As previously noted, many believe that Tanzanite is a stone of transformation and spiritual growth. This belief is directly linked to its color, which is thought to represent the vastness of the sky and the infinite potential of the universe. It is seen as a gem that can open the mind to new perspectives and encourage a deeper understanding of oneself and the world.
Tanzanite is also believed to enhance communication, intuition, and self-awareness. It is often associated with the throat and third-eye chakras in alternative healing practices, which are linked to clear communication and spiritual insight. For this reason, it is considered an excellent stone for those seeking to improve their self-expression or develop their intuitive abilities.
The gem’s association with new beginnings and fresh chapters makes it a popular gift for milestones such as birthdays, anniversaries, or the start of a new venture. It is seen as a stone that helps one navigate change with clarity and curiosity, leaving behind the old and embracing the new.
Jewelry and Market Value
Tanzanite’s captivating color and unique properties have made it a popular choice for a wide variety of jewelry pieces. Its versatility allows it to be set in everything from classic to contemporary designs.
Tanzanite Rings: A Tanzanite ring is a classic and timeless choice. The deep blue-violet hue adds a touch of sophistication and elegance to any ring design. Whether set in white gold, yellow gold, or platinum, a Tanzanite ring is sure to become a cherished heirloom. However, due to its moderate hardness and perfect cleavage, it is advisable to choose protective settings like bezels or halo designs for rings intended for frequent wear.
Tanzanite Necklaces: For a versatile and eye-catching accessory, Tanzanite necklaces are an excellent choice. The gemstone’s vibrant color makes it a focal point in any necklace design, from simple pendants to intricate statement pieces. Worn casually or for a special occasion, a Tanzanite necklace adds a touch of glamour and individuality.
Tanzanite Earrings: Tanzanite earrings are a popular choice for those who want to add a pop of color to their ensemble. They can range from simple studs, perfect for daily wear, to elaborate drop earrings that showcase the stone’s beauty and movement.
In terms of market value, Tanzanite is considered the most valuable of the four December birthstones (Blue Topaz, Blue Zircon, Tanzanite, and Turquoise). Its value is driven by several factors: its rarity, its exclusive origin in Tanzania, and the increasing demand for this unique gem. The finest quality Tanzanite, characterized by a deep, saturated blue-violet color and exceptional clarity, commands premium prices. The value is also influenced by the stone's size, with larger, high-quality stones being exponentially more valuable.
Care and Cleaning
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 more fragile than many other popular gemstones.
Durability Concerns: With a hardness of 6 to 7 on the Mohs scale, Tanzanite can be scratched by harder materials. It should be stored separately from other jewelry to prevent contact that could cause abrasion. Its perfect cleavage means it is susceptible to chipping or breaking if knocked against a hard surface. Therefore, it is not the best choice for jewelry that will be subjected to rough wear, such as everyday rings or bracelets.
Cleaning Instructions: Cleaning Tanzanite requires a gentle approach. The safest method is to use warm water, a mild dish soap, and a soft brush (like a baby toothbrush). Gently scrub the stone and its setting, then rinse thoroughly to remove any soap residue. Avoid using harsh chemicals, ultrasonic cleaners, or steam cleaners, as these can damage the stone or its setting.
Storage: When not being worn, Tanzanite jewelry should be stored in a soft cloth pouch or a lined jewelry box, away from other pieces that could scratch it.
Conclusion
Tanzanite stands as a remarkable gemstone, both for its breathtaking beauty and its unique story. For those born on December 15th, it is not merely a birthstone but a symbol of rarity, transformation, and spiritual depth. Its journey from a chance discovery in the hills of Tanzania to a globally cherished gem is a testament to its enduring appeal.
While it shares the month of December with other blue stones, Tanzanite distinguishes itself with its singular origin, its intense violet-blue color, and its powerful metaphysical associations. Its value as a collector's item and a centerpiece for fine jewelry is well-established, and its status as a modern classic is secure. Understanding its properties and respecting its fragility are key to preserving this extraordinary gem. As a symbol of new beginnings and infinite possibility, Tanzanite is a truly special gift for anyone celebrating a December 15th birthday.