PG0013 : 2.88ct Violet Blue Tanzanite – 10x8mm

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LEARN MORE TANZANITE STONE

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• Value
• Information
• Charecteristics
• Source
• Care

Tanzanite Gemstone – Royal Gemstone from Africa to the world

When Tiffany & Co. first laid eyes on a mineral specimen of zoisite with a...

21
Jul

TRADE NAME

Tanzanite Stone

Mineral : Zoisite

Mohs Hardness : 6.5

Refractive Index : 1.69 – 1.70

Specific Gravity : 3.10 – 3.38

VALUE

Tanzanite Stone has seen a rapid increase in popularity in the last few years. Its mineral name is Zoisite and is naturally reddish brown in color, it is through heat treatment that it achieves its beautiful blue to violet color.

INFORMATION

Tanzanite was discovered in 1967, at the foot of Mt. Kilimanjaro in Tanzania (which gave the stone its name). Tanzanite is a pleochroic gemstone, meaning it can appear to have different colors under different light. In natural light, the stone resembles Sapphire in color, however in fluorescent light, it is closer to Amethyst in color. They are naturally trichroic, meaning the show blue, red-violet and yellow-green colors depending on the light on its three crystal axes.

The blue to violet color is their most coveted property. It is rare to find a naturally blue stone in the rough, so most achieve their color through heat treatments. The stone is heated to 500-600 degrees Celsius for about half an hour.

Charecteristics : Zoisite Variety

Tanzanite is the most prized Zoisite, but not the only one. Here are some others worth mentioning:

• Zoisite - Only blue to violet Zoisites are considered Tanzanite Stone. You can also find transparent zoisite and in a range of colors, like pink, yellow and brown.
• Thulite - Thulite is the national gemstone for Norway. It is pink in color and translucent to opaque in clarity. They make excellent cabochons and faceted pieces are rare. Other names for this gemstone are Unionite and Rosaline.
• Anyolite - Anyolite is a lapidary rock containing chrome-rich green zoisite, black Hornblende and some large but opaque Ruby. Expert cutters turn the stone into cabochons and carvings. It is also known as Ruby-in-Zoisite.
• Synthetics - There are currently no known synthetic Tanzanite. However, simulants and imitations are known to exist.

Enhancements

It is safe to assume that all rich blue Tanzanite have been submitted to a stable heat treatment.

SOURCE

• Tanzanite - As the name suggests, the sole source for Tanzanite is Tanzania. More specifically in the Merelani Hills, situated in the Lelatema Mountains.
• Anyolite - Deep green crystals, colored by chromium and with Ruby crystals are found in Longido, Tanzania.
• Thulite - United States: California; Nevada; North Carolina; Washington. Canada; Greenland; Japan; Norway.

CARE

Tanzanite Stone hardness rages from 6 to 7 on the Mohs scale. However, it has a tendency to cleave and is rather brittle, which is not ideal for daily wear. Tanzanite are best used in occasional pieces or behind protective settings. They should be cleaned with a soft brush, mild detergent, and warm water.

Stone Sizes & collectibles

• Rough Tanzanite gemstone have been found weighing hundreds of carats and reaches the largest size of all Zoisite in faceted gems.
• Smithsonian Institution (Washington, DC) houses a 122.7-carat blue Tanzanite and an 18.2-carat blue cat’s eye Tanzanite.
• A private collector owns a 220-carat Tanzanite.