Tanzanite Gemstone Information

Tanzanite Gemstones

is an exotic, vivid blue, kissed by purple hues. Tanzanite has the beauty and rarity to rival any gemstone variety. It is the ultimate prize of a gemstone safari. Tanzanite is mined only in Tanzania at the feet of the majestic Mount Kilimanjaro.

One of the most popular blue gemstones available today, tanzanite occurs in a variety of shapes and sizes and also provides a striking assortment of tonal qualities. Rarely pure blue, tanzanite almost always display its signature overtones of violet. In smaller sizes, tanzanite tends toward the lighter tones and the lavender color is more common. While in larger sizes, tanzanite typically displays deeper, richer color.

No gem discovered in East Africa has had more of an impact on the world gemstone market than tanzanite, found for the first time in 1967 and named after the country of its birth by Tiffany & Co in New York, who introduced the gemstone to the world market in 1969.

The prices, uses and value of Tanzanite can differ greatly, depending on the size and quality of the  individual gemstone. AJS Gems is your source for the highest quality colored gems from across the globe, available at Bangkok direct wholesale prices. Creating the finest jewelry starts with finding the best gemstones, and the best gemstones are found at AJS Gems.

Why Buy Loose Gemstones Instead of Pre-Set Jewelry?
There are many reasons, but basically it boils down to value and choice.

When buying your tanzanite loose instead of a pre-set stone, you can be sure you are getting the best value for your money. Loose gemstones are less expensive, a better value, and you can really see what you are paying for. The most important part of getting the right price and finding the best value is to first see what you're getting. A jewelry setting will hide the inclusions inside a gem, and can deepen or brighten its color. With a loose stone you can much more easily inspect the gem and see it for what it really is.  In this way you can get a better idea of its true worth and be sure you are paying a fair price.

The second advantage of buying a loose gemstone is choice.  You are free to pick the exact color, cut, shape and variety of the stone for the setting of your dreams, be it yellow gold, white gold, platinum or silver; prong set or bezel set with diamond accents.  You can experience the joy of creating your very own, one-of-a-kind jewelry design. Choose from a variety of jewelry settings and styles to create a completely original presentation that will perfectly suit your individual gemstone and will be as unique as you are!

Tanzanite Ring        Tanzanite Jewelry

At AJS Gems, you will find a large collection of fine quality tanzanite, hand selected by us for your fine jewelry.


Origin Tanzania
Color Blue, yellow brown, pink, blue-purple, gray, greenish
Refractive Index 1.691
Chemical Composition  CaA13(O/OH/SiO4)Si207
Hardness 6 - 6.5
Density 3.35
Crystal Structure Orthorhombic
Month December

Tanzanite is a blueish-purple gemstone variety of the mineral zoisite, which is a calcium aluminium hydroxy sorosilicate belonging to the epidote group of minerals. Tanzanite has a hardness of 6 to 6 1/2 on the Mohs scale. The durability of Tanzanite is fair, due to its hardness.

Tanzanite has a refractive index of 1.691, with a birefringence of 0.009.  The refractive index (RI), measured using a refractometer, is an indication of the amount light rays are bent by a mineral. Birefringence is the difference between the minimum and maximum RI. When birefringence is high, light rays reflect off different parts of the back of a stone causing an apparent doubling of the back facets when viewed through the front facet. 

Most gems have a crystalline structure. Crystals have planes of symmetry and are divided into seven symmetry systems. The number of axes, their length, and their angle to each other determine the system to which a crystal belongs.  Tanzanite is in the orthorhombic crystal system, with a "bladed" crystal habit.

Tanzanite can sometimes be mistaken for blue sapphire, but tanzanite can have very pronounced pleochroism, which reflects different colors from different angles. "Pleochroism" is an optical phenomenon due to the double refraction of light which is divided into two "polarized" paths at a 90 degree angle to each other. When viewed from the top or front, tanzanite's hue will appear blue to violet-blue, and when viewed from the back it will appear violet to bluish-purple.


The source of its mesmerizing color is that tanzanite is trichroic: that is, it shows different colors when viewed in different directions. One direction is blue, another purple, and another bronze, adding subtle depths to the color. When tanzanite is found in the ground, the bronze color dominates. However, with gentle heating, the bronze color subsides and the cutter can watch the blue color bloom in the stone. Tanzanite specimens that have a predominantly blue color can attract higher prices than purplish-blue varieties, because these crystals tend to form with the blue color axis oriented along the width of the crystal as opposed to its length.

A small percentage of the gem tanzanite found is not blue or purple. The stone can exhibit a green color. Like the browns, heat will eliminate the greens, so most tanzanite that exhibits green overtones in the rough are heated to produce the blue/violets that the market seems to have an insatiable demand for. However, occasionally, a green stone is attractive enough to be left untreated. The green and parti-color stones are therefor a natural, rare and delightful addition to the tanzanite family.

Blue tanzanite obtains its distinct violet-blue color from trace amounts of vanadium and chrome tanzanite (chrome zoisite) obtains its vivid green coloration from its chromium content.


Loose tanzanite is commonly faceted into many different shapes, although the most popular are Pear Cut, Oval Cut, Round Cut  Heart Cut, Cushion Cut, Trillion Cut and Marquise Cut.

When fashioning a loose Tanzanite gemstone, cut orientation is critical to take maximum advantage of the color. 

Many tanzanite gemstones are heated.  The majority of tanzanite stones come out of the ground a yellow-brown color with slight hints of violet. The stones are then heat-treated at low temperature to create the rich blues and purples that have made tanzanite one of the most popular high value gems on the market today.


The natural color of the tanzanite crystal (the mineral zoisite), prior to the application of heat, is brown or bronze, which can be especially pronounced when observing the stone on its 'C' axis. Tanzanite that has not been exposed to heat in its natural state can be heat-treated to 500C - 620C (932F) to produce the deeper blue color that is characteristic of the stone.  This treatment is considered permanent and stable.

AJS Gems fully discloses any and all treatments to our gemstones.

Tanzanite is a rare mineral only found in the Mererani or Merelani hills tanzanite mining area of Tanzania. Located in the Simanjiro district, the Merelani mining area is 16 kilometers south of the Kilimanjaro International Airport, and 70km south-east of Arusha, at the base of Mt. Kilimanjaro. 
Tanzanite Source
To this day, the only source of Tanzanite gemstones in the world is this several square mile area in the Merelani Hills. This limited supply makes Tanzanite 1000 times more rare than Diamond, leading to its high value in the gemstone world.

Legend has it that Tanzanite was first discovered when some brown gemstone crystals lying on the dry earth were caught in a fire set by lightning that swept through the grass-covered hills. The Masai herders driving cattle in the area noticed the beautiful blue color and picked the crystals up, becoming the first tanzanite collectors.
Tanzanite is relatively new on the gemstone market, but has left its mark. Some in the market have added tanzanite to the elite class of the major gemstones: Diamond, ruby, sapphire, emerald, opal, and tanzanite. Others are calling it the "gemstone of the year." Its popularity is quite phenomenal.

Tanzanite is so popular, it was the first gemstone added to the birthstone list since 1912 by the American Gem Trade Association.

AJS Gems Wholesale Loose Tanzanite

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