Tanzanite is a captivating gemstone known for its remarkable blue-violet hues. Among its many intriguing properties, one notable characteristic is its potential to exhibit color change. In this comprehensive article, we will delve into the phenomenon of color change in tanzanite gemstones, exploring the factors that contribute to this intriguing effect, the range of color changes observed, and the significance it holds for this rare and beautiful gemstone.
How Tanzanite Is Formed
Tanzanite is a unique gemstone that holds the distinction of being found in only one location on Earth—Tanzania, East Africa. The formation of tanzanite involves a fascinating geological process that spans millions of years. Here’s an overview of how tanzanite is formed:
Origin and Geological Setting:
Tanzanite is a variety of the mineral zoisite. Its formation can be traced back to the Neoproterozoic Era, approximately 550 million years ago. The specific geological setting of Tanzania played a crucial role in the creation of tanzanite. It is believed that tanzanite formed in metamorphic rocks within the Merelani Hills of northern Tanzania.
Metamorphism:
The formation of tanzanite begins with the presence of preexisting rocks, particularly blue schist and gneiss, in the region. These rocks undergo intense heat and pressure due to tectonic forces, leading to the process of metamorphism. The heat and pressure cause the minerals within the rocks to recrystallize and rearrange, resulting in the formation of new minerals and gemstones.
Interaction of Fluids:
During the metamorphic process, hydrothermal fluids—hot water-rich solutions—play a vital role in the formation of tanzanite. These fluids carry various elements and minerals, including vanadium, which is a crucial component for the unique blue-violet color of tanzanite. The fluids interact with the existing minerals in the rock, leading to the formation and deposition of tanzanite crystals.
Crystallization and Growth:
As the hydrothermal fluids circulate through the rock, they come into contact with minerals such as aluminum, calcium, silica, and vanadium, which are essential for tanzanite formation. The conditions of temperature, pressure, and mineral concentration are favorable for the growth of tanzanite crystals. Over an extended period, tanzanite crystals gradually form and develop within the rock matrix.
Secondary Processes:
After the initial formation, secondary processes such as weathering and erosion come into play. These processes expose the tanzanite-bearing rocks to the Earth’s surface, allowing them to be discovered and mined. Tanzanite deposits are found in pockets or veins within the host rocks, and miners extract the gemstones through careful excavation.
The unique geological history of Tanzania, with its combination of metamorphism, hydrothermal activity, and mineral-rich fluids, has given rise to the rare and beautiful gemstone known as tanzanite. Its formation is a testament to the complex and fascinating processes that shape our planet over vast periods of time.
What color is Tanzanite?
Tanzanite is a captivating gemstone renowned for its unique and mesmerizing color. It is primarily known for its captivating shades of blue-violet, often described as a vivid or intense blue with a touch of purple. The color of tanzanite can vary across a spectrum, ranging from light pastel hues to deep, rich tones.
The gemstone’s color is a result of pleochroism, a property that allows it to exhibit different colors when viewed from different angles. Tanzanite can appear predominantly blue when viewed from one angle, and then shift to purple or violet when observed from another angle. This pleochroic effect adds to the gem’s allure and gives it a sense of depth and vibrancy.
The most highly prized tanzanite gemstones possess a vibrant and saturated blue-violet hue. The presence of a deep blue color combined with a rich purple overtone is particularly desirable. These intense hues are considered more valuable and sought after by collectors and connoisseurs.
It’s important to note that the exact color of tanzanite can vary due to lighting conditions and individual gemstones’ unique characteristics. However, the captivating blue-violet color remains the defining feature and one of the main attractions of this exceptional gemstone, making it a popular choice for jewelry and a coveted addition to any gemstone collection.
Does Tanzanite Change Color?
Tanzanite, a rare and beautiful gemstone, does not typically undergo significant color change under normal lighting conditions. It is primarily known for its vibrant blue or violet-blue color. However, it is worth noting that tanzanite is a pleochroic gemstone, meaning it can exhibit different colors when viewed from different angles.
The pleochroism of tanzanite manifests as a slight variation in color intensity rather than a dramatic color change. When observed under various lighting conditions and viewed from different angles, tanzanite can display shades of blue, violet, and even hints of burgundy or red. This characteristic is a result of its crystal structure and the selective absorption of light along different crystallographic axes.
It’s important to understand that tanzanite’s pleochroism is not as pronounced as that of some other gemstones like alexandrite, which can showcase dramatic shifts from green to red. Tanzanite’s color change, if any, is more subtle and may not be readily noticeable without careful observation. While tanzanite is not renowned for its significant color change, it does exhibit pleochroism, displaying different shades of blue, violet, and occasionally hints of burgundy or red when viewed from various angles and lighting conditions.
Tanzanite care and maintenance
Proper care and maintenance are essential to preserve the beauty and longevity of tanzanite jewelry. Here are some guidelines to ensure the well-being of your tanzanite pieces:
Avoid exposure to extreme temperatures:
Tanzanite is sensitive to sudden temperature changes, so it’s crucial to avoid subjecting your tanzanite jewelry to extreme heat or cold. Extreme temperature fluctuations can cause thermal shock, leading to potential damage or cracks in the gemstone.
Protect from physical impact:
Tanzanite has a moderate hardness on the Mohs scale, which means it is not as durable as some other gemstones. To prevent scratches or chips, it’s advisable to store tanzanite jewelry separately in a padded box or pouch to avoid contact with harder materials. Be cautious while engaging in activities that may expose the gem to potential impacts.
Avoid exposure to chemicals:
Tanzanite should be protected from harsh chemicals, such as household cleaners, chlorine, and other solvents. These substances can damage or discolor the gemstone. It’s advisable to remove tanzanite jewelry before swimming, using cleaning products, or engaging in activities that involve contact with chemicals.
Gentle cleaning:
To clean tanzanite, use a soft brush, lukewarm soapy water, and gently scrub the gemstone. Rinse thoroughly with clean water and pat dry with a soft, lint-free cloth. Avoid using ultrasonic cleaners or steam cleaners as they may damage the stone. Regular cleaning helps maintain the gem’s luster and brilliance.
Professional inspections:
Periodically have your tanzanite jewelry inspected by a professional jeweler. They can assess the setting’s integrity, ensure the gemstone is secure, and address any maintenance or repair needs.
By following these care and maintenance guidelines, you can enjoy the beauty of your tanzanite jewelry for years to come and preserve its value.
Conclusion:
Tanzanite’s ability to display color change is a captivating aspect of this remarkable gemstone. The interplay of light and the presence of trace elements within the crystal structure give rise to this intriguing phenomenon. Color change tanzanite offers a unique visual experience and holds a special place among gemstone enthusiasts. Understanding the factors that contribute to color change and appreciating its rarity and aesthetic appeal enhances our admiration for this exceptional gemstone.
