Everything You Want to Know About Tanzanite
Tanzanite is a unique gemstone known for its intense purple-blue color and striking color change under different lighting conditions. The stone was not discovered until 1967, making it one of the youngest gemstones currently used in jewelry.
Due to its rarity and unique color, tanzanite has quickly carved out an important place for itself in the world of gemstones and jewelry.
On this page, you can read all about the properties of tanzanite, its various colors, its formation, and how to care for this unique gemstone.
Tanzanite at a Glance
Mineral group: Zoisite
Chemical composition: Ca₂Al₃(SiO₄)(Si₂O₇)O(OH)
Hardness: 6 to 7 on the Mohs scale
Suitable for everyday wear: ★★★☆☆
Most common colors: Blue and blue-purple
Birthstone: December
Properties of Tanzanite
Tanzanite is a variety of the mineral zoisite and was first discovered in northern Tanzania, at the foot of Mount Kilimanjaro. To this day, this remains the only location in the world where tanzanite is mined commercially.
One of tanzanite’s most remarkable properties is pleochroism: depending on the viewing angle and lighting conditions, different colors may be visible, such as blue, purple, and violet.
With a hardness of 6 to 7 on the Mohs scale, tanzanite is less scratch-resistant than, for example, sapphire or spinel. As a result, the stone requires a little more care, especially when set in a ring that is worn every day.
Colors of Tanzanite
Most tanzanites range in color from blue and blue-purple to deep violet.
Common shades include:
- Light blue
- Blue-violet
- Deep Blue
- Purple-blue
- Violet
- Lavender
Color intensity plays an important role in the valuation of the stone. Deeper and more saturated colors are generally considered the most valuable.
Natural, treated, and lab-grown tanzanite
Natural tanzanite
Virtually all tanzanite used in jewelry is naturally formed.
Treated tanzanite
Most of the tanzanite on the market is heat-treated to bring out its blue and purple hues more vividly. This treatment is widely accepted within the gemstone industry.
Lab-grown tanzanite
Lab-grown tanzanite plays virtually no role in the jewelry industry and is available only in limited quantities.
Origin and Locations
Tanzanite is mined exclusively in a small area in northern Tanzania, near the Merelani Hills.
This limited source of the stone contributes significantly to its rarity and popularity.
Care
Tanzanite requires a little more care than harder gemstones such as diamond, sapphire, or spinel.
Clean the stone with lukewarm water, a soft cloth or a soft brush, and a little mild soap. Avoid hard impacts, and it is best not to wear tanzanite jewelry while doing heavy work or playing sports.
Summary
Tanzanite is a rare and extraordinary gemstone known for its intense purple-blue color and striking play of color. Thanks to its unique appearance and limited sources, the stone is beloved by collectors of exceptional gemstones. Although tanzanite requires a bit more care than harder gemstones, it remains a wonderful choice for anyone looking for something special.
Looking for more information about other gemstones? Check out the complete gemstone guide for an overview of all gemstones and their properties.