Tanzanite: The Exclusive African Gemstone

In 1968, Tiffany & Co. introduced a new collection featuring a striking gemstone known as tanzanite. This translucent bluish-violet stone quickly captivated jewelers due to its uniqueness. Tanzanite is exclusively mined in one location on Earth: at the foot of Mount Kilimanjaro in Tanzania.

In this article, we will delve into the history of tanzanite, its characteristics, pricing, grading, mining processes, and more.

Discovery of Tanzanite

The discovery of tanzanite is attributed to various accounts. According to the official version recognized by the Tanzanian government, the first tanzanite crystal was found in January 1967 by a local resident named Jumanne Mhero Ngoma, who was later awarded a certificate and a reward of 50,000 shillings.

Another popular account, particularly in the West, tells of a tailor named Manuel de Souza, affectionately known as “Mad Manuel.” He aspired to become wealthy through the extraction of gold and precious stones. After earning some money from sewing, de Souza traveled to Tanzania in search of gold and ruby deposits, accompanied by local Maasai hunters.

Despite not finding anything significant initially, de Souza remained hopeful. On July 7, 1967, he discovered a translucent purple-red stone in the Merelani hills area. Mistaking it for sapphire due to its color, he later realized it was much softer than sapphire after testing its hardness. He sent the stone for examination, which revealed it to be a unique variety of the mineral zoisite.

Tanzanite: A Rare Variety of Zoisite

Zoisite is a semi-precious stone that was discovered in the early 19th century and is mined in various locations worldwide, including Eurasia, North and South America, and Africa. Its appearance can vary significantly, ranging from transparent to matte, and its colors can include yellow, emerald, and raspberry.

However, tanzanite is a rare form of zoisite that is found only in Tanzania. This vibrant stone closely resembles sapphire and other blue gemstones, which caught the attention of Tiffany & Co. Henry B. Platt, the great-grandson of the company’s founder, Charles Tiffany, named the stone “tanzanite,” helping to establish its global reputation.

What Makes Tanzanite Special?

Striking Appearance
Tanzanite is renowned for its vivid and deep color. The stone exhibits different hues depending on the lighting, similar to the famous blue or white dress meme. It can appear golden-brown, purple, or blue-violet from various angles, a phenomenon known as pleochroism.

The stone’s appearance is also influenced by its processing. Jewelers often enhance the natural blue color of tanzanite through cutting and heat treatment, making it resemble blue sapphire or blue diamond. However, other colors, such as green tanzanite, also exist.

There is a myth that tanzanite was used as the “Heart of the Ocean” diamond in the movie “Titanic,” as director James Cameron reportedly liked its appearance on screen. However, this is not true; the film used synthetic spinels for the necklaces.

Uniqueness
Tanzanite is unique because it is only mined in Tanzania, making it rarer than diamonds. The deposits formed at the junction of two tectonic plates under specific temperature and pressure conditions, resulting in tanzanite’s distinctive blue color due to the presence of chromium and vanadium ions. No other similar deposits are known to exist.

Relatively Low Price
In terms of hardness, tanzanite is softer than many other gemstones, scoring between 6.5 and 7 on the Mohs scale, similar to glass. This softness contributes to its lower price compared to diamonds, sapphires, and rubies. Although tanzanite has not been synthesized, imitations may exist, so buyers should exercise caution.

Experts suggest that tanzanite jewelry can be a good investment, as the only deposit in northern Tanzania is gradually depleting, leading to a potential increase in prices for high-quality stones.

Mining Tanzanite

Tanzanite is exclusively mined on the Merelani Plateau in the Arusha region near Kilimanjaro. The mining area spans approximately two by four kilometers. Until the 1990s, private companies conducted the mining, but the Tanzanian government later took control, requiring special licenses for tanzanite extraction.

The mining area is divided into four zones: A, B, C, and D. Zones A and C are designated for foreign companies, while B and D are reserved for Tanzanian miners. Zone C is the most productive and accessible for mining. Since 2014, the British company Sky Associates Group Ltd. has been responsible for mining in this zone.

Initially, tanzanite was found on the surface, but now miners must dig down to depths of 200-400 meters to extract the stones. The mined stones are sorted and processed on-site. Following the construction of a 24-kilometer perimeter wall around the mines to enhance security and prevent smuggling, production increased significantly, rising from 147.7 kilograms in 2018 to a record 781.2 kilograms in 2019.

Choosing High-Quality Tanzanite

Tanzanite’s quality is heavily influenced by the skill of the cutter. A grading system evaluates the stone based on four criteria: color, clarity, cut, and carat weight.

• Color: Treated tanzanite is typically graded in two shades: bluish violet (violet dominant) and violet blue (blue dominant), assessed on a ten-point scale based on color intensity.

• Clarity: The presence of inclusions is categorized into four groups:

  • EC (Eye Clean – defect-free)
  • SI (Slightly Included – minor inclusions)
  • MI (Moderately Included – noticeable inclusions)
  • HI (Heavily Included – significant inclusions)

• Cut: This evaluates the angles, proportions, and brilliance of the stone. The cut quality is graded as Excellent, Very Good, Good, Fair, or Poor.

• Carat Weight: Measured in carats, where one carat equals 0.2 grams.

In 2020, the largest tanzanite stones were discovered by Maasai miner Saniniu Laizer and his team, weighing 9.27 kg and 5.103 kg. The Tanzanian government purchased these stones for $3.3 million, and Laizer planned to invest the money in community development, including building a school and shopping mall.

Tanzanite Jewelry: Cost and Popularity

Tanzanite has become a well-known gemstone in the jewelry market, celebrating its fiftieth anniversary in 2017. It has gained popularity among celebrities, with figures like Anne Hathaway, Cate Blanchett, and Beyoncé wearing tanzanite jewelry.

In 2002, the American Gem Trade Association included tanzanite in its Birthstone List, designating it as the birthstone for December. It is also a traditional gift for the 24th wedding anniversary.

The price for gold tanzanite rings starts at around $300, while earrings begin at approximately $150. Due to its captivating nature, tanzanite jewelry is often bold and substantial, frequently accented with diamonds, leading to a wide price range. For example, a platinum Tiffany ring featuring tanzanite and diamonds can cost $13,200.

Visitors can view tanzanite jewelry not only in stores but also at the world’s only Tanzanite Museum, located near the mining area in Arusha. This museum, established by The Tanzanite Experience jewelry company, showcases various tanzanite pieces and includes a workshop where Maasai women create traditional African-style jewelry. These items can be purchased at branded stores across Africa or online.