Tanzanite

Tanzanite is a mesmerizing gemstone renowned for its intense blue-violet hue. It is considered one of the most captivating gemstones in the world. Tanzanite’s unique color and rarity have captured the attention of gem enthusiasts and jewelry lovers worldwide.

1. Definition and Characteristics:
   • Tanzanite is a variety of the mineral zoisite, which belongs to the epidote mineral group.
   • It was first discovered in the Merelani Hills of Tanzania in 1967 and was named after its country of origin.
   • The gemstone’s color ranges from vivid blue to violet, with pleochroism, meaning it exhibits different colors when viewed from different angles.
   • Tanzanite is known for its remarkable trichroism, displaying blue, violet, and burgundy hues in different crystal directions.
   • It has a hardness of 6.5 to 7 on the Mohs scale, making it suitable for various jewelry applications.
2. Discovery and Mining:
   • Tanzanite’s discovery is attributed to a Maasai tribesman named Ali Juuyawatu, who found vibrant blue crystals on the foothills of Mount Kilimanjaro in northern Tanzania.
   • The gemstone’s rarity is due to its exclusive occurrence in a small area of northern Tanzania, specifically the Merelani Hills near the town of Arusha.
   • Tanzanite is primarily mined through small-scale operations, with miners working in tunnels and manually extracting the gemstone-bearing rock.
   • The mining process involves careful excavation, sorting, and processing of the ore to recover the tanzanite crystals.
3. Geological Formation and Rarity:
   • Tanzanite’s geological formation is unique and fascinating. It is believed to have formed through a combination of heat and pressure during tectonic activities that occurred around 585 million years ago.
   • The formation of tanzanite is associated with the presence of metamorphic rocks and the interaction of fluids rich in elements like vanadium, chromium, and manganese.
   • Tanzanite’s rarity stems from its geological origins being confined to a specific area in northern Tanzania, which contributes to its limited availability.

Tanzanite’s striking color, intriguing geological origins, and scarcity have contributed to its desirability in the gemstone market. It has gained significant popularity among collectors, jewelry designers, and gemstone enthusiasts due to its unique beauty and limited supply.

Physical properties

1. Color: Tanzanite is renowned for its captivating blue-violet color. The gemstone exhibits a range of shades, from a vibrant blue to a deep violet. The intensity of the color is a crucial factor in determining the value and desirability of Tanzanite.
2. Clarity: Tanzanite can vary in terms of clarity. It may contain inclusions, which are natural internal flaws or tiny mineral crystals within the gemstone. The presence of inclusions can affect the transparency and overall appearance of the stone. Tanzanite with high clarity and minimal inclusions is considered more valuable.
3. Hardness: Tanzanite has a hardness of 6.5 to 7 on the Mohs scale of mineral hardness. This makes it relatively durable and suitable for jewelry use. However, it is important to note that Tanzanite is not as hard as gemstones like sapphires or diamonds, so it requires careful handling and protection to avoid scratches or damage.
4. Crystal Structure: Tanzanite belongs to the orthorhombic crystal system. Its crystals have a prismatic shape with well-defined facets. The crystal structure of Tanzanite contributes to its pleochroism, where the gemstone displays different colors when viewed from different angles.
5. Refractive Index: The refractive index measures how light is bent as it passes through the gemstone. Tanzanite typically has a refractive index ranging from 1.691 to 1.700. This property affects the gemstone’s brilliance and how light interacts with it, contributing to its overall appearance.
6. Specific Gravity: Tanzanite has a specific gravity ranging from 3.35 to 3.38. Specific gravity indicates the density of the gemstone compared to the density of water. This property helps gemologists distinguish Tanzanite from other similar-looking gemstones.
7. Cleavage: Tanzanite exhibits good cleavage, which means it can split along certain planes or directions. Gem cutters need to take this into account when shaping and faceting Tanzanite to minimize the risk of fractures.

Understanding the physical properties of Tanzanite is crucial for evaluating its quality, durability, and overall suitability for different jewelry applications. These properties, along with the gemstone’s remarkable color, contribute to its allure and desirability in the world of gemstones.

Optical properties

The optical properties of Tanzanite play a significant role in its visual appearance and overall beauty. Here are the key optical properties of Tanzanite:

1. Refractive Index: Tanzanite has a refractive index ranging from approximately 1.691 to 1.700. The refractive index determines how much light is bent or refracted as it passes through the gemstone. Tanzanite’s refractive index contributes to its brilliance and sparkle.
2. Pleochroism: Tanzanite is highly pleochroic, meaning it exhibits different colors when viewed from different crystallographic directions. In the case of Tanzanite, it displays a blue hue when viewed from one direction, violet from another, and sometimes even a burgundy color from a different angle. The pleochroic effect adds depth and interest to the gemstone’s appearance.
3. Birefringence: Tanzanite has a relatively high birefringence due to its orthorhombic crystal structure. Birefringence refers to the difference in refractive indices between two perpendicular crystallographic directions. In Tanzanite, this property can result in a doubling of facets or edges when viewed through the gemstone, a phenomenon known as doubling.
4. Dispersion: Tanzanite exhibits moderate to high dispersion, which refers to the ability of a gemstone to separate white light into its spectral colors or fire. The dispersion in Tanzanite contributes to the play of colors and adds to its visual appeal.
5. Transparency: Tanzanite is typically transparent to translucent, allowing light to pass through the gemstone with minimal obstruction. High-quality Tanzanite with good transparency allows for excellent light transmission, enhancing its brilliance and color display.
6. Luster: Tanzanite exhibits a vitreous to subadamantine luster, giving it a desirable and reflective shine. The gemstone’s luster adds to its overall attractiveness and visual appeal.

Understanding the optical properties of Tanzanite is crucial for gemologists, jewelers, and gemstone enthusiasts. These properties influence the way light interacts with the gemstone, affecting its color display, brilliance, and visual effects such as pleochroism and dispersion. It is these optical characteristics that make Tanzanite a captivating and sought-after gemstone.

Chemical composition

Tanzanite is a variety of the mineral zoisite, which belongs to the epidote mineral group. The general chemical formula for zoisite is Ca2Al3(SiO4)(Si2O7)O(OH). However, Tanzanite contains additional elements that give it its distinct blue-violet color. The blue coloration is primarily due to the presence of trace amounts of vanadium (V), while the violet color is attributed to the presence of chromium (Cr). The specific chemical composition of Tanzanite can be expressed as (Ca2Al3(SiO4)(Si2O7)O(OH)) with vanadium and chromium impurities.

It’s important to note that the presence of these impurities, particularly vanadium and chromium, is responsible for the exceptional coloration of Tanzanite. The combination of these elements in the crystal lattice of Tanzanite gives it its unique blue and violet hues, which are highly prized in the gemstone world.

The chemical composition of Tanzanite provides valuable insights into its mineralogical classification and the elements responsible for its remarkable color. Understanding the presence of vanadium and chromium helps gemologists and scientists identify and distinguish Tanzanite from other similar gemstones.

Mining and Production

Mining and production processes related to Tanzanite involve the extraction of the gemstone from the earth, sorting and processing of the rough material, cutting and polishing of the gemstones, and finally, the creation of finished Tanzanite jewelry. Here’s an overview of the mining and production of Tanzanite:

1. Mining:
   • Tanzanite is primarily mined in the Merelani Hills, located near the town of Arusha in northern Tanzania. This area is the only known source of Tanzanite in the world.
   • Mining operations in the region are predominantly small-scale, employing local miners who work in tunnels and manually extract the gemstone-bearing rock.
   • Tanzanite mining involves several steps, including excavation, blasting, and removal of overburden to access the gemstone-rich zone.
   • Miners use hand tools and basic machinery to extract the rough Tanzanite-bearing rock from the ground. This rock is then transported to the surface for further processing.
2. Sorting and Processing:
   • Once the rough Tanzanite-bearing rock is extracted, it goes through a sorting process. Miners separate the Tanzanite-bearing rock from other non-gemstone material, such as waste rock and soil.
   • The sorted material is then transported to processing facilities where it undergoes various techniques to extract the Tanzanite crystals. This can involve crushing, grinding, and washing the rock to separate the Tanzanite from the surrounding matrix.
   • After the Tanzanite crystals are separated, they go through a cleaning process to remove any remaining impurities and debris.
3. Cutting and Polishing:
   • The cleaned Tanzanite crystals are sent to gemstone cutting and polishing facilities, where highly skilled lapidaries shape the rough crystals into finished gemstones.
   • Lapidaries assess each Tanzanite crystal to determine the best way to cut it, taking into account factors such as color, clarity, and size. They aim to maximize the beauty and value of each gemstone.
   • Cutting Tanzanite requires precision and expertise to ensure optimal color retention and minimize the loss of material during the cutting process.
   • After the cutting process, the Tanzanite gemstones go through polishing to enhance their brilliance and luster. This involves using various polishing techniques and abrasive materials to achieve a smooth and reflective surface.
4. Creation of Finished Jewelry:
   • Once the Tanzanite gemstones are cut and polished, they are ready to be used in jewelry creation.
   • Jewelry designers and manufacturers acquire the Tanzanite gemstones and incorporate them into various designs, such as rings, earrings, pendants, and bracelets.
   • Skilled artisans craft the jewelry pieces using different metals, such as gold or silver, along with other gemstones or diamonds to complement the Tanzanite’s beauty.
   • The finished Tanzanite jewelry is then distributed to retailers or sold directly to consumers.

It is worth noting that mining and production of Tanzanite are subject to regulations and efforts to promote responsible and sustainable practices. Measures are taken to ensure the welfare of miners, minimize environmental impact, and prevent the illicit trade of Tanzanite.

Overall, the mining and production processes of Tanzanite involve a combination of traditional mining techniques, skilled craftsmanship, and modern technologies to bring the captivating gemstone from the earth to the market in the form of exquisite jewelry.

Major Tanzanite mining areas

The major Tanzanite mining areas are located in the Merelani Hills of northern Tanzania, near the town of Arusha. This region is the only known source of Tanzanite in the world. The mining operations primarily take place in the following areas within the Merelani Hills:

1. Block C:
   • Block C is the main mining area within the Merelani Hills and is known for producing a significant portion of the world’s Tanzanite.
   • The mining activities in Block C are carried out by small-scale miners, often organized in cooperatives or working independently.
   • This area has been a rich source of Tanzanite since its discovery in 1967.
2. Block D:
   • Block D is another important mining area within the Merelani Hills.
   • It is situated to the west of Block C and also yields Tanzanite of varying qualities.
   • Block D has seen considerable mining activities over the years and contributes to the overall production of Tanzanite.
3. Block B:
   • Block B is located south of Block C and has been a less significant mining area compared to the other blocks.
   • Tanzanite production in Block B has been relatively limited, but it has still contributed to the overall supply of the gemstone.

These major mining areas within the Merelani Hills have been the primary sources of Tanzanite for several decades. The artisanal miners operating in these areas use manual mining techniques, extracting the Tanzanite-bearing rock through tunnels and basic mining equipment.

It’s important to note that Tanzanite mining is subject to regulations and oversight by Tanzanian authorities to ensure responsible and sustainable practices. Efforts are made to address environmental concerns, support local communities, and prevent illegal mining and trade of Tanzanite.

Tanzanite Jewelry

Tanzanite jewelry is highly sought after for its captivating blue-violet color and rarity. The unique beauty of Tanzanite makes it a popular choice for various types of jewelry, ranging from rings and earrings to pendants and bracelets. Here are some common types of Tanzanite jewelry:

1. Tanzanite Rings:
   • Tanzanite rings are a popular choice for engagement rings, cocktail rings, and everyday statement pieces.
   • The gemstone’s vibrant blue-violet color and brilliance make it an eye-catching centerpiece in ring designs.
   • Tanzanite rings are often complemented with diamonds or other gemstones, enhancing the overall aesthetic and adding sparkle.
2. Tanzanite Earrings:
   • Tanzanite earrings are available in various styles, including studs, dangle earrings, and hoop earrings.
   • They can feature single Tanzanite gemstones or incorporate multiple gemstones, such as a pair of matching Tanzanites or combinations with diamonds or other colored gemstones.
   • Tanzanite earrings add a touch of elegance and sophistication to any ensemble.
3. Tanzanite Pendants and Necklaces:
   • Tanzanite pendants and necklaces are versatile jewelry pieces that can be worn for both casual and formal occasions.
   • Pendant designs often showcase a single Tanzanite gemstone in various shapes, such as round, oval, pear, or cushion-cut.
   • Necklaces may feature a string of Tanzanite beads or incorporate Tanzanite as accent stones in a pendant design.
4. Tanzanite Bracelets:
   • Tanzanite bracelets are adorned with Tanzanite gemstones set in a row or combined with other gemstones for added brilliance.
   • Tennis bracelets, bangle bracelets, or charm bracelets can be crafted using Tanzanite, creating a stunning wrist accessory.
5. Tanzanite Jewelry Sets:
   • Tanzanite jewelry sets offer a coordinated look, featuring matching pieces such as earrings, a pendant, and a ring.
   • These sets are designed to create a harmonious and stylish ensemble, perfect for special occasions or as a gift.

When purchasing Tanzanite jewelry, it’s important to consider factors such as the gemstone’s color, clarity, cut, and carat weight. High-quality Tanzanite with intense blue-violet color and good clarity is typically more valuable. Additionally, the choice of metal, such as gold or silver, can complement the gemstone and enhance the overall design.

Tanzanite jewelry not only serves as a stunning adornment but also holds the allure of owning a rare gemstone with a captivating story of its Tanzanian origins.

Tanzanite uses and application

Tanzanite is a versatile gemstone that finds applications in various areas. Here are some common uses and application areas of Tanzanite:

1. Jewelry:
   • Tanzanite is primarily used in jewelry and is highly valued for its exceptional color and rarity.
   • It is often cut and faceted into various shapes, including round, oval, cushion, and pear, to create exquisite pieces of jewelry such as rings, earrings, necklaces, bracelets, and pendants.
   • Tanzanite jewelry is cherished for its vibrant blue-violet hues, which can range from intense blue to deep violet, making it a captivating gemstone for both casual and formal occasions.
2. Collectibles and Investment:
   • Tanzanite’s limited supply and rarity make it an attractive gemstone for collectors and investors.
   • High-quality Tanzanite gemstones with desirable color, clarity, and size are highly valued and can appreciate in value over time.
   • Collectors often seek unique and rare Tanzanite specimens or gemstones with exceptional characteristics, such as large sizes, exceptional color saturation, or outstanding clarity.
3. Fashion and Accessories:
   • Tanzanite can be used in fashion and accessories beyond traditional jewelry.
   • It can be incorporated into designer pieces, such as brooches, hair accessories, or cufflinks, adding a touch of elegance and sophistication.
   • Tanzanite beads or cabochons can also be used in textile embellishments, embroidery, or as decorative elements in high-end fashion.

It’s important to note that while Tanzanite has various applications, it should be handled and cared for with caution. Due to its moderate hardness, Tanzanite can be susceptible to scratches and damage if not handled properly. It is advisable to remove Tanzanite jewelry when engaging in activities that may subject it to potential impact or abrasion.

Overall, Tanzanite’s exceptional beauty and rarity have made it a sought-after gemstone in the world of jewelry, collecting, and metaphysical practices. Its vivid blue-violet color and unique properties continue to captivate gemstone enthusiasts and consumers alike.

Famous tanzanite jewelry pieces

There are several famous Tanzanite jewelry pieces that have gained recognition for their beauty, craftsmanship, and historical significance. Here are a few notable examples:

1. The Queen of Kilimanjaro:
   • The Queen of Kilimanjaro is one of the most famous Tanzanite jewelry pieces.
   • Created by renowned jewelry designer Michael Scott, this necklace features a 242-carat Tanzanite as its centerpiece.
   • The necklace also incorporates over 100 carats of diamonds set in platinum.
   • The Queen of Kilimanjaro was unveiled in 1988 and has since become an iconic representation of Tanzanite’s allure.
2. The Midnight Star:
   • The Midnight Star is an exquisite Tanzanite ring owned by actress Elizabeth Taylor.
   • The ring showcases a remarkable 116-carat cushion-cut Tanzanite surrounded by 16 carats of diamonds.
   • This stunning piece was gifted to Elizabeth Taylor by her husband Richard Burton and became a cherished part of her jewelry collection.
3. The Grandidierite Necklace:
   • Designed by Tiffany & Co., the Grandidierite Necklace features a rare 115-carat grandidierite gemstone as its focal point.
   • The necklace also incorporates Tanzanite gemstones, diamonds, and platinum.
   • The unique combination of the rare grandidierite gemstone and Tanzanite creates a captivating and distinctive piece of jewelry.
4. The Greenbrier Tiara:
   • The Greenbrier Tiara is a magnificent headpiece commissioned by the Greenbrier Resort in West Virginia, USA.
   • The tiara showcases several gemstones, including a large pear-shaped Tanzanite, surrounded by diamonds and set in platinum.
   • This regal and elegant tiara has become an iconic symbol of luxury and glamour.

These famous Tanzanite jewelry pieces have not only showcased the beauty and allure of Tanzanite but have also played a role in raising awareness and appreciation for the gemstone. They exemplify the exceptional craftsmanship and artistry that goes into creating exquisite jewelry pieces featuring Tanzanite as the centerpiece.

Alternatives to Tanzanite

While Tanzanite is a unique and captivating gemstone, there are several alternatives available that offer similar colors or characteristics. Here are some popular alternatives to Tanzanite:

1. Blue Sapphire:
   • Blue sapphire is a gemstone known for its rich blue color, making it a close alternative to Tanzanite.
   • Sapphires are durable and come in a range of blue shades, from deep navy to lighter blue hues.
   • They are widely used in jewelry, including rings, earrings, and pendants.
2. Blue Topaz:
   • Blue topaz is a more affordable alternative to Tanzanite and is available in various shades of blue, including light sky blue and vibrant Swiss blue.
   • Blue topaz is a popular gemstone for both casual and formal jewelry designs.
   • It is often used as a more budget-friendly option to achieve a similar blue gemstone look.
3. Iolite:
   • Iolite, also known as “water sapphire,” can resemble Tanzanite in its blue-violet coloration.
   • Although it is less commonly used, iolite is a beautiful gemstone with a unique bluish-violet hue and good clarity.
   • It can be an alternative choice for those seeking a similar color range as Tanzanite.
4. Amethyst:
   • Amethyst is a purple gemstone that can be a more affordable substitute for the violet hues of Tanzanite.
   • While it does not possess the blue tones of Tanzanite, it offers a range of purple shades from light lavender to deep violet.
   • Amethyst is widely used in jewelry and is often seen in rings, earrings, and necklaces.
5. Lapis Lazuli:
   • Lapis lazuli is a deep blue gemstone with specks of golden pyrite and occasional white calcite veins.
   • It has been used for centuries in jewelry and art and can be an alternative for those seeking a vivid blue gemstone with a unique appearance.

It’s important to note that while these gemstones share some similarities with Tanzanite in terms of color, they may differ in other characteristics such as hardness, brilliance, and rarity. When considering alternatives to Tanzanite, it’s advisable to choose a gemstone that aligns with your preferences, budget, and desired qualities.

Summary of key points

• Tanzanite is a rare and valuable gemstone that is renowned for its blue-violet color, ranging from intense blue to deep violet.
• It is a variety of the mineral zoisite and is found exclusively in the Merelani Hills of northern Tanzania.
• Tanzanite is notable for its pleochroism, meaning it can exhibit different colors when viewed from different angles.
• The gemstone’s physical properties include a hardness of 6.5 to 7 on the Mohs scale and a specific gravity ranging from 3.35 to 3.55.
• Tanzanite’s optical properties include strong trichroism, high refractive index, and vitreous to sub-adamantine luster.
• Its chemical composition consists of calcium, aluminum, silicon, oxygen, and traces of vanadium, which is responsible for its unique blue-violet color.
• Tanzanite is primarily used in jewelry, and it is commonly featured in rings, earrings, necklaces, pendants, and bracelets.
• Some famous Tanzanite jewelry pieces include the Queen of Kilimanjaro, the Midnight Star ring, the Grandidierite Necklace, and the Greenbrier Tiara.
• Alternatives to Tanzanite include blue sapphire, blue topaz, iolite, amethyst, and lapis lazuli.
• Tanzanite mining takes place in the Merelani Hills, and the production process involves extraction, sorting, processing, cutting, polishing, and the creation of finished jewelry.
• Tanzanite is associated with various metaphysical properties and is believed to promote spiritual growth, intuition, and emotional balance.

Tanzanite’s exceptional beauty, rarity, and captivating color have made it a highly sought-after gemstone in the world of jewelry and collectibles.

FAQ

How is Tanzanite formed?

Tanzanite is formed through a combination of geological processes. It is believed to have originated from the metamorphism of a specific type of igneous rock called “blue zoisite.” The rock undergoes heat and pressure deep within the Earth’s crust, causing chemical changes that transform it into Tanzanite.

Where is Tanzanite found?

Tanzanite is found exclusively in a small region of northern Tanzania, near the foothills of Mount Kilimanjaro. The primary mining area is the Merelani Hills, located near the town of Arusha. This area is the only known source of Tanzanite in the world.

What makes Tanzanite rare?

Tanzanite’s rarity is due to its limited geographic occurrence. It is found in a single location in northern Tanzania, making it a geologically scarce gemstone. Additionally, the mining of Tanzanite is challenging and complex, further contributing to its rarity.

What gives Tanzanite its color?

Tanzanite’s stunning blue-violet color is attributed to the presence of trace amounts of vanadium within the gemstone. The interaction of vanadium with the crystal structure of Tanzanite produces its unique color range, from blue to violet, depending on the lighting conditions and viewing angles.

How old is Tanzanite?

Tanzanite is relatively young in terms of geological age. It is estimated to be around 585 million years old, which is considered young compared to other gemstones like diamonds or rubies. Tanzanite’s formation occurred during tectonic activities that shaped the region’s geology.

Can Tanzanite be found anywhere else?

As of the current knowledge and available information, Tanzanite is found exclusively in the Merelani Hills of Tanzania. Extensive exploration efforts have been made, but no other significant sources of Tanzanite have been discovered elsewhere in the world.

References

1. Fritsch, E., & Shigley, J. E. (1991). Tanzanite: Born from Lightning. Gems & Gemology, 27(4), 262-277.
2. Rossman, G. R., & Mielke, R. E. (1993). Blue coloration of tanzanite by intervalence charge transfer: A UV-VIS-NIR and IR study. American Mineralogist, 78, 439-444.
3. Laurs, B. M. (2005). The rise of tanzanite: How an extraordinary gemstone came to market. Gems & Gemology, 41(2), 100-119.
4. Pardieu, V., & Saul, M. (2010). Tanzanite deposits of Merelani. In G. Blanco-Moreno, T. S. Hayes, & J. J. Griffin (Eds.), Geology and Mineral Resources of the Kilimanjaro Region: A Modern Synthesis of Classic Studies (pp. 99-110). Geological Society of America Special Paper 461.
5. Gems & Gemology Magazine. (Various issues). Gemological Institute of America.