Tanzanite is a captivating gemstone, a relatively recent addition to the world of colored stones, and a celebrated December birthstone. Discovered in 1967 in the Merelani Hills of northern Tanzania, this gem quickly gained recognition for its unique and vibrant hues, ranging from deep blues to rich violets. Its story is one of rapid ascent in the gemological world, propelled by the endorsement of Tiffany & Co., and its enduring appeal lies in its rarity, beauty, and the intriguing lore surrounding its origins. This article will delve into the history, geological formation, gemological properties, symbolism, and care of this remarkable gemstone.
History and Lore
Prior to 1967, the gem now known as tanzanite was simply a brownish variety of the mineral zoisite. Its transformation into the sought-after blue-violet gemstone occurred through heat treatment, a process that enhances its color and reveals its true potential. The Masai tribespeople of Tanzania are credited with the initial discovery of the unusually colored crystals, though the story of its “official” discovery is interwoven with legend. Some accounts suggest that a lightning strike ignited a wildfire, naturally heat-treating the zoisite and revealing the vibrant colors that would later captivate the world.
While lacking the extensive historical lore of older birthstones, tanzanite’s relatively short history is nonetheless compelling. It was named “tanzanite” by Tiffany & Co. in honor of its country of origin, Tanzania, recognizing its potential for international appeal. In 1968, Tiffany launched a major advertising campaign, effectively introducing tanzanite to a global audience and establishing it as a desirable gemstone. Today, it is not only recognized as a December birthstone but also as the gem commemorating the 24th wedding anniversary. Its rapid rise to prominence has earned it the nickname “the gemstone of the 20th century,” a testament to its unique appeal and the successful marketing efforts that brought it to the forefront of the gem market.
Geological Formation and Sources
Tanzanite is exceptionally rare because it is found commercially only in a limited area: the Merelani Hills of northern Tanzania, situated near the base of Mount Kilimanjaro. The geological conditions necessary for its formation are highly specific, contributing to its scarcity. The gem is formed within metamorphic rocks, and mining operations in the Merelani Hills involve digging over 100 meters deep into the earth to recover the precious stones.
The likelihood of finding tanzanite deposits anywhere else in the world is considered almost impossible. This singular origin reinforces its exclusivity and contributes to its value. The mining landscape is characterized by grass-covered hillsides, scrub brush, and rocky soil, a stark contrast to the vibrant beauty hidden beneath the surface. Both large mechanized operations and smaller-scale artisanal mining contribute to the supply of this unique gemstone.
Gemological Properties
Tanzanite is a variety of the mineral zoisite, belonging to the silicate family. It typically exhibits a range of colors, from blue to purple-bluish, with the most valuable stones displaying a pure, rich blue hue. A defining characteristic of tanzanite is its strong pleochroism – the ability to display different colors when viewed from different angles. Specifically, tanzanite exhibits three distinct colors depending on the viewing direction: predominantly blue with violet undertones, more violet aspects often modified with purple, and a combination of blue and purple. This phenomenon creates a mesmerizing, multidimensional effect that sets it apart from many other gemstones.
The gem’s hardness ranges from 6 to 7 on the Mohs scale, making it relatively durable but susceptible to scratching and abrasion. While resistant to the effects of normal heat, light, and common chemicals, tanzanite can crack if exposed to very high temperatures or sudden temperature changes. It is also vulnerable to attack by hydrochloric and hydrofluoric acids.
Most tanzanite undergoes heat treatment to enhance its color, a process that is considered stable and permanent. The treatment is often undetectable, and does not introduce any additional durability concerns. The quality and value of tanzanite are largely determined by the saturation of its color, with deeply colored specimens being the most rare and desirable. Larger stones generally exhibit greater color saturation.
Here's a table summarizing key gemological properties:
| Property | Description |
|---|---|
| Mineral | Zoisite |
| Chemical Family | Silicate |
| Color | Blue, violet, purple-bluish |
| Hardness (Mohs) | 6 - 7 |
| Pleochroism | Exhibits three distinct colors |
| Treatment | Commonly heat-treated to enhance color |
| Origin | Merelani Hills, Tanzania |
Symbolism and Metaphysical Beliefs
While a relatively new gemstone, tanzanite has quickly acquired symbolic meaning. The blue hues are associated with spirituality, connecting to both the heavens and life-giving water, and are believed to provide physical and emotional vitality. The purple shades symbolize nobility and strength, historically linked to royalty. The ability of tanzanite to display multiple colors simultaneously further enhances its spiritual significance, potentially embodying the combined energies of blue and purple.
The lore surrounding its discovery, linking it to a wildfire and the power of nature, also contributes to its mystique. Tanzanite is associated with inner transformation, healing, and spiritual self-discovery, believed to help wearers unlock their potential and embrace new beginnings. It is considered a meaningful choice for those seeking enlightenment and growth.
Care and Cleaning
Due to its hardness of 6 to 7 on the Mohs scale, tanzanite is best suited for settings in earrings or pendants, minimizing the risk of scratches and abrasion. While it can be worn in rings with a protective mounting, daily wear is not recommended.
Cleaning tanzanite is best achieved with warm, soapy water. Ultrasonic and steam cleaners should never be used, as they can damage the gemstone. Gentle cleaning with a soft brush and mild soap will help maintain its brilliance and beauty. It is important to avoid exposing tanzanite to high temperatures or sudden temperature changes, as this can cause cracking.
Conclusion
Tanzanite, a gem discovered in the late 20th century, has rapidly established itself as a highly prized and sought-after gemstone. Its unique pleochroism, vibrant colors, and limited origin contribute to its rarity and value. From its intriguing discovery story to its symbolic associations with transformation and spirituality, tanzanite continues to captivate gem enthusiasts and jewelry lovers alike. Its enduring appeal solidifies its position as a significant gemstone and a cherished December birthstone.