Tanzanite, a colored stone with a rich history and unique characteristics, has captivated gem enthusiasts since its discovery. First introduced to the world by Tiffany & Co. in 1968, tanzanite quickly gained popularity for its beauty and rarity. Tanzanite's striking blue-violet color and pleochroism set it apart from other gems.
Tanzanites have been heavily marketed by Tiffany & Co.
As the demand for unique and vibrant gemstones grows, tanzanite has become a valuable addition to the jewelry market. Its status as a December birthstone and its versatility in various jewelry designs make it highly desirable. This guide will explore the formation, sources, characteristics, treatments, evaluation, costs, and astrological significance of tanzanite, providing a comprehensive understanding of this remarkable gemstone. Here is everything you need to know about the Tanzanite stone.
1. Tanzanite: Formation & Occurrence
Tanzanite is a stone of unique origin and formation, the geological processes that lead to the formation of tanzanite are intricate and fascinating. Tiffany & Co. is largely responsible for bringing tanzanite to the market, and its growing popularity today. Tanzanite is a blue variety of the mineral Zoisite, which forms under specific high pressure and temperature conditions. These conditions occur in a unique geological setting where the continental crust has been stretched and pulled apart, allowing the gemstone to crystallize within metamorphic rocks.
The structural properties and composition of tanzanite also play a crucial role in its appearance. Its chemical composition primarily consists of calcium aluminium silicate, with traces of vanadium, which is responsible for blue-violet coloration. The presence of vanadium and other trace elements during the stone's formation leads to the vibrant hues that make tanzanite so distinctive.
Tanzanite's scarcity adds to its allure and value. The gemstone is found only in a small area of Tanzanite near the Merelani Hills, roughly 4.3 miles long and 1.2 miles wide, making it much rarer than diamonds. This limited geographic occurrence means that tanzanite is in high demand and can command significant prices, especially for high-quality stones with deep, saturated colors.
2. Where Is Tanzanite Found?
Tanzanite is primarily found in Northern Tanzania, specifically in the Merelani Hills near Mount Kilimanjaro. This region is the exclusive source of tanzanite stones, making it one of the world's rarest gems. Discovered in 1967, the gemstone is named after its country of origin, Tanzania. The hills host the only known deposits of tanzanite, with mining operations concentrated in a relatively small area. The geological conditions in these hills are unique, allowing the formation of tanzanite, which is a variety of the mineral zoisite.
The rarity of Tanzanite is due to its limited geographic origins. Unlike other gemstones such as topaz, garnet, peridot, and aquamarine, which can be found in multiple locations around the world, Tanzanite's occurrence is restricted to this specific region. This exclusivity contributes to its desirability and value in the jewelry market.
Tanzanite occurs in found only in one location on Earth - near the Merelani Hills in Tanzania
3. Color Range of Tanzanite
Tanzanite is renowned for its stunning color spectrum, which ranges from deep blues to vibrant violets and rich purples. The unique hues of tanzanite stones are primarily influenced by trace elements, particularly vanadium, present during the gem's formation. When tanzanite is mined, it often appears as a reddish-brown stone. However, once it undergoes heat treatment, which is standard practice, the true vibrant colors are revealed.
One of the most fascinating characteristics of tanzanite is its pleochroism. Pleochroism refers to a stone's ability to exhibit different colors when viewed from different angles. In the case of tanzanite, this means that the stone can display blue, violet, and burgundy hues depending on the orientation of the crystal. This effect is caused by the way the crystal structure interacts with light, making tanzanite a particularly dynamic and visually intriguing gemstone.
Tanzanite colors range from pale blues and lilacs to intense, deep blues and purples. The most prized tanzanite stones are those with a strong, saturated blue, often compared to fine sapphire. However, the violet and purple stones are also highly valued and are appreciated for their unique beauty. A well-cut tanzanite can showcase multiple hues simultaneously, enhancing its overall appearance and making each piece of tanzanite jewelry unique.
4. Common Inclusions in Tanzanite
Tanzanite, like all gemstones, can contain inclusions that affect its clarity and value. The most common types of inclusions found in tanzanite include:
- Liquid Inclusions: These are pockets of fluid trapped within the gemstone during its formation, they can appear as tiny bubbles or channels and are usually visible under magnification. While they may not be noticeable to the naked eye, they can impact the overall clarity of the stone.
- Mineral Inclusions: These are small crystals of other minerals that became encased within the tanzanite as it formed. They can vary in size, shape, and color, and can sometimes add unique visual interest to the stone. However, a larger or more prominent one can detract from the gem's transparency and brilliance.
- Fractures: Fractures, or internal cracks, can occur naturally or as a result of the gemstone being subjected to stress. They are usually more visible than liquid or mineral impurities and can significantly impact the durability and clarity of tanzanite. Fractures can sometimes be treated to improve the stone's appearance, but untreated fractures generally lower the gem's value.
5. Common Treatments & Enhancements of Tanzanite
Tanzanite is often treated to enhance its color and improve its overall appearance. The most common treatment for tanzanite is heating or thermal enhancement, which helps to bring out the vibrant blue and violet hues that make the gemstone so desirable.
Virtually all tanzanite stones available in the market today have been heat treated. When tanzanite is first mined, it often has a brownish or greenish hue. By heating the stone to temperatures between 400 and 600 degrees Celsius, the brown or green tones are removed, revealing the stunning blue and violet colors. This process is stable and permanent, meaning the enhanced colors will not fade over time. Heating is a widely accepted practice in the gemstone industry and does not detract from the gem's value as long as it is disclosed to buyers.
Untreated Tanzanite stones occur in lacklustre green & brown colors
The effects of heat treatment on tanzanite are significant. Without this treatment, the gem would not exhibit the striking colors that are characteristic of high-quality tanzanite. Consequently, heat-treated tanzanite tends to be more valuable and sought after than untreated stones, which are rare and often less visually appealing.
| Mineral | Zoisite |
|---|---|
| Colour Span | Pale violet-blue to an intense vivid blue |
| Popular Origins | Found only in Tanzania (near the Merelani Hills) |
| Mohs Hardness | 6.50 (on a scale of 10) |
| Common Treatments | Heat Treatment/Thermal Enhancement |
| Birthstone | December |
Tanzanite - A Quick Snapshot
6. Evaluating the Quality of Tanzanite
When evaluating tanzanite, the 4Cs—Color, Clarity, Cut, and Carat weight—are crucial in determining its quality and value.
- Color: The most important factor for tanzanite. The finest stones exhibit a deep, saturated blue or violet-blue color. Lighter hues are less valuable but still appreciated for their beauty. The intensity and saturation of the color significantly influence the gem's desirability.
- Clarity: Tanzanite typically has fewer inclusions compared to other gemstones. However, stones with high clarity and minimal impurities are more valuable.
- Cut: The cut of tanzanite affects its brilliance and how the color is displayed. A well-cut tanzanite will showcase its pleochroism, revealing different colors from different angles. The quality of the cut can enhance the stone’s visual appeal and overall value.
- Carat Weight: Larger tanzanite stones are rarer and more valuable. However, the overall quality, including color, clarity, and cut, must also be considered. A smaller stone with superior color and clarity can be more valuable than a larger one with poorer attributes.
7. How Much Does Tanzanite Cost?
The price of tanzanite typically ranges between $100 and $800 per carat, largely dependent on the quality of the stone. Factors that influence this cost include color, clarity, cut, carat weight, and market demand. High-quality tanzanite, specifically those graded as "AAA" or "D-Block", can reach prices of $400 to $675 per carat for stones weighing over 3 carats. Additionally, tanzanite exhibiting a rich blue-violet color is deemed most valuable, while stones with noticeable green components will significantly decrease in price. These prices may vary depending on the retailer's geographic location, as well as the demand and supply dynamics of the gem.
8. Tanzanite in Astrology
Tanzanite is the recommended birthstone for December, symbolizing spiritual growth and transformation. In astrology, tanzanite is believed to possess healing properties that support emotional healing and spiritual growth. It is often associated with the throat and third-eye chakras, aiding in chakra alignment and enhancing communication, intuition, and psychic abilities.
Many believe that wearing tanzanite can help dispel negativity, promote calmness, and encourage positive transformation. Its deep blue and violet hues are thought to inspire a sense of peace and facilitate a deeper understanding of oneself and the universe. As the birthstone for December, tanzanite is cherished not only for its beauty but also for its reputed healing properties, aiding in emotional balance, spiritual growth, and chakra alignment.
Buy tanzanite and other exquisite stones such as topaz, sapphires, turquoise, garnet, peridot, and aquamarine at Precious Earth. Each stone in our collection is carefully selected to offer you the finest quality and most stunning beauty.
