December boasts a fascinating array of birthstones – Turquoise, Tanzanite, Blue Zircon, and Blue Topaz – offering a spectrum of colors and symbolic meanings. Among these, Tanzanite stands out as a relatively recent discovery and, notably, one of the most valuable. This article will delve into the origins, gemological properties, historical context, and current market value of Tanzanite, exploring why this violetish-blue gemstone has rapidly gained prominence in the world of colored stones.
A Recent Discovery with a Rich History
While the tradition of associating gemstones with birth months stretches back to ancient civilizations, the recognition of Tanzanite as a December birthstone is a comparatively modern development. The gemstone was first discovered in 1967 in the Merelani Hills of northern Tanzania, a location that remains the sole source of Tanzanite worldwide. The discovery occurred during prospecting for sapphire, but the unusual blue-violet mineral quickly captured attention.
In 1968, Tiffany & Co. recognized the gem’s potential and introduced it to the market, naming it “Tanzanite” in honor of its country of origin. This strategic branding played a crucial role in establishing Tanzanite’s desirability and elevating its status within the gemological world. The gemstone’s introduction coincided with a growing consumer interest in colored gemstones, providing a unique and captivating alternative to the more traditional options.
Geological Formation and Unique Origins
Tanzanite is a transparent variety of the mineral zoisite, a calcium aluminum silicate. Its distinctive color is not inherent to the mineral in its natural state; rather, it develops through heat treatment. The gem’s color arises from trace amounts of vanadium within the crystal structure.
The geological conditions required for Tanzanite formation are exceptionally rare. It is formed within a specific type of metamorphic rock created by intense heat and pressure during the tectonic activity that formed the Great Rift Valley. This unique geological history explains why Tanzanite is found exclusively in a small area near the Merelani Hills in Tanzania. The limited geographical source contributes significantly to its value and rarity.
Gemological Properties and Characteristics
Tanzanite exhibits a captivating range of colors, typically displaying violetish-blue to bluish-violet hues. The intensity of the color, and specifically the balance between blue and violet, significantly impacts its value. Deeper color saturation is highly prized, with stones exhibiting more blue than violet being the most coveted and expensive.
Smaller Tanzanites often display less saturated color, while larger stones – those exceeding five carats – tend to exhibit richer, more vibrant tones. The quality of the cut is also crucial, as it directly influences how the gemstone reflects and displays its color.
While specific refractive index and hardness data are not provided in the sources, Tanzanite is noted for its pleochroism, meaning it displays different colors when viewed from different angles. This optical phenomenon adds to its visual complexity and appeal.
Here's a summary of Tanzanite's key properties, based on the provided sources:
| Property | Description |
|---|---|
| Mineral | Zoisite (a calcium aluminum silicate) |
| Color | Violetish-blue to bluish-violet |
| Origin | Merelani Hills, Tanzania (sole source) |
| Treatment | Typically heat-treated to enhance color |
| Key Feature | Pleochroism (displays different colors from different angles) |
| Value Factor | Color saturation (more blue = higher value) |
Symbolism and Modern Significance
Although the ancient roots of birthstone symbolism are well-established, the specific meanings associated with Tanzanite are more contemporary. The gemstone is often linked to transformation and spiritual enlightenment, making it a fitting choice for those seeking personal growth and positive change.
The relatively recent discovery of Tanzanite also lends it a unique appeal. Unlike many traditional birthstones with centuries of lore, Tanzanite represents a modern connection to the earth and a celebration of contemporary gemological discoveries. Its association with December provides a vibrant and distinctive alternative to the more traditional Turquoise, Blue Zircon, and Blue Topaz.
Market Value and Rarity
Tanzanite is considered a valuable gemstone, with prices ranging from $1,000 to $1,500 per carat for high-quality stones. The price is influenced by several factors, including color, clarity, cut, and carat weight. Larger, deeply saturated stones command the highest prices.
The gemstone’s rarity is a significant driver of its value. As the sole source of Tanzanite is a geographically limited area in Tanzania, the supply is finite. This scarcity, coupled with increasing demand, has contributed to a steady appreciation in value over the years.
In March 2024, Naomi Sarna created a sculpture named L’Heure Bleu (“blue hour” in French) from a 703.4-carat Tanzanite, breaking the record for the largest cut Tanzanite. This event further highlighted the gemstone’s potential for exceptional size and beauty, and its increasing recognition within the art and gemological communities.
Care and Cleaning
While specific care instructions are not detailed in the provided sources, general guidelines for gemstone care can be applied. Tanzanite, like many colored gemstones, should be protected from harsh chemicals, extreme temperatures, and ultrasonic cleaners. Gentle cleaning with warm, soapy water and a soft brush is recommended. Due to its potential for cleavage, care should be taken to avoid sharp impacts.
Conclusion
Tanzanite represents a compelling addition to the world of birthstones. Its relatively recent discovery, unique geological origins, captivating color, and increasing rarity have established it as a highly sought-after gemstone. As a December birthstone, it offers a modern and vibrant alternative, symbolizing transformation and spiritual enlightenment. The gemstone’s continued popularity and rising value underscore its significance in the gemological landscape, solidifying its position as a treasured and increasingly valuable gem.