Tanzanite is a captivating gemstone, notable for its vibrant blue-violet hues and relatively recent entry into the world of recognized birthstones. Officially added to the December birthstone list in 2002, it joins blue zircon and blue topaz as options for those born in the final month of the year. This article will explore the history, geological origins, gemological properties, and cultural significance of this unique and increasingly popular gem.
A Fortuitous Discovery in Tanzania
The story of tanzanite’s discovery is relatively well-documented, beginning in January 1967. Jumanne Mhero Ngoma, a Masai tribesman, stumbled upon sparkling blue stones in the Mererani Hills of northern Tanzania, within the Kiteto district. Recognizing the potential value of his find, he alerted authorities. Three years later, he received a certificate of recognition from President Julius Nyerere and a reward of 50,000 Tanzanian shillings. In 1984, the Tanzania Commission for Science and Technology formally recognized his discovery with a certificate for scientific achievement.
Initially mistaken for sapphire, the stones were soon identified as a vibrant blue variety of zoisite, a mineral previously known primarily in its brown form. The gem was subsequently named “tanzanite” by Tiffany & Co. in honor of its country of origin, Tanzania. This naming strategy proved crucial in establishing the gem’s market presence and desirability.
Geological Formation and Limited Sources
Tanzanite’s geological story is central to its rarity and value. Unlike many gemstones found in multiple locations worldwide, tanzanite is currently found in only one place on Earth: a small area of approximately seven square kilometers on the foothills of Mount Kilimanjaro in Tanzania. This limited geographical source makes it significantly rarer than diamonds.
The gem’s distinctive blue color is attributed to trace amounts of vanadium, combined with intense heat during its formation. The zoisite mineral undergoes a metamorphic process, resulting in the unique pleochroism that characterizes tanzanite – the ability to display different colors when viewed from different angles. Skilled cutting is essential to maximize the attractive blue and violet hues. Most tanzanite undergoes heat treatment to enhance these colors, a common and accepted practice within the gemological industry.
Gemological Properties
Tanzanite belongs to the zoisite mineral group. Its hardness ranges from 6 to 7 on the Mohs scale of mineral hardness, making it relatively durable but requiring careful handling to avoid scratches and damage.
Key gemological properties include:
- Chemical Formula: A complex calcium aluminum silicate with vanadium.
- Color: Typically violet-blue, bluish-violet, or blue.
- Crystal System: Triclinic
- Pleochroism: Strong, displaying different colors depending on the viewing angle.
- Refractive Index: Not specified in the provided sources.
- Specific Gravity: Not specified in the provided sources.
- Clarity: Varies, with eye-clean stones being highly valued.
Tanzanite is commonly cut into round, pear, and heart shapes to best showcase its color and brilliance.
Historical and Cultural Significance
While tanzanite’s discovery is recent, it has quickly gained cultural significance, particularly within Tanzania. Among the Maasai tribes, the gem is traditionally presented to wives to celebrate childbirth and bestow good luck and prosperity upon the newborn. This practice highlights the gem’s association with new beginnings and positive energy.
The gem’s association with December as a birthstone is a more recent development, formalized in 2002 by the Jewelry Industry Council of America. It also serves as the traditional gemstone for the 24th wedding anniversary.
The initial naming of the gem as “diaphanite” by mineralogist Nordenskiöld, following its discovery in Russia’s Ural Mountains, is a historical footnote. However, with Russia as the sole source at the time, the Russian royalty renamed the gem after Tsar Alexander II in the 19th century. This historical context underscores the long-standing tradition of associating gemstones with power and prestige.
Tanzanite in the Modern Gemstone Landscape
Tanzanite’s emergence as a popular gemstone is a testament to effective marketing and its inherent beauty. Tiffany & Co.’s branding played a significant role in establishing its desirability, and its unique color quickly captured the attention of jewelry designers and consumers.
The gem’s rarity continues to drive its value, and concerns about its potential extinction due to its limited source are frequently voiced. This scarcity contributes to its appeal as a valuable and collectible gemstone. While synthetic alternatives exist for many gemstones, tanzanite’s unique geological origin and color profile make it difficult to replicate convincingly.
Care and Cleaning
Due to its hardness of 6 to 7 on the Mohs scale, tanzanite requires careful handling. It is susceptible to scratches from harder materials and can be cleaved with a sharp blow. Cleaning should be performed with mild soap and warm water, using a soft brush to remove any dirt or grime. Ultrasonic cleaners and steam cleaners should be avoided, as they can potentially damage the stone. It is recommended to store tanzanite jewelry separately from other gemstones to prevent scratching.
Conclusion
Tanzanite represents a fascinating chapter in the world of gemstones. Its relatively recent discovery, coupled with its limited geographical source and captivating color, has quickly established it as a highly sought-after gem. From its origins with a Masai tribesman to its recognition as a December birthstone and a symbol of good fortune, tanzanite embodies a unique blend of geological rarity, cultural significance, and modern appeal. Its enduring popularity is a testament to its inherent beauty and the enduring allure of rare and precious gemstones.