Why are tanzanite gemstones blue?

Tanzanite Stones


Tanzanite StonesTiffany and Company coined the term Tanzanite to describe gem-quality specimens of the mineral zoisite, a blue tint. Tiffany might have sold the material under the mineralogical term "blue zoisite," but they decided that calling it "tanzanite" would pique customers' attention and make it easier to promote. The name "tanzanite" was given since northern Tanzania is home to the world's sole commercially viable tanzanite deposit. The tanzanite stones limited geographic origin is reflected in the name. The mines are spread out over an eight-square-mile area in the Merelani Hills, near Mount Kilimanjaro's base and the city of Arusha. Even though nearly all of the country's most famous gemstones have been recognised and used for hundreds of years, commercial quantities of tanzanite were not discovered until the 1960s.

In the brief period since then, it has surpassed sapphire as the most desirable blue stone. It is one of just a few gems of any colour uncovered and brought to the wider public interest in the last century. Tiffany's advertising and the lovely blue colour of tanzanite were largely responsible for its meteoric growth in popularity. Tanzanite was chosen as a modern birthstone for December in 2002 due to its expanding popularity.

The exclusive and royal blue colour of tanzanite stones

Colourless, grey, yellow, brown, pink, green, blue, and violet are only some of the natural colours of the mineral zoisite. The term "tanzanite" refers to a zoisite colour variant that varies from blue to violet to violetish purple. It's not uncommon for a colour variant to have a name like this. For red to slightly purplish red specimens of the mineral corundum, the word "ruby" is used; for purple specimens of the crystal quartz, the name "amethyst" is used; and for green specimens of the mineral beryl, the word "emerald" is used. Each of these minerals comes in a variety of colours.

In the 1960s, the discovery of translucent blue zoisite crystals sparked interest in the gem. Laboratory investigations soon after that finding revealed that heating could increase the hue of some naturally blue stones. They also discovered that heating might turn some naturally brown or green zoisite into a stunning blue zoisite (tanzanite!). There would be enough tanzanite discovered due to these discoveries to sustain a marketing campaign that would introduce the gem to millions around the world.

What gives these tanzanite stones the blue colour?

Small quantities of vanadium within the zoisite mineral structure give tanzanite its blue colour. The oxidation state of vanadium is changed when vanadium-bearing zoisite is heated to 600 degrees Celsius for around 30 minutes, and this change creates or enhances the blue colour. When compared to what is done to gems like rubies and sapphires, tanzanite's heat treatment is quite gentle. These jewels may be heated to temperatures ranging from 1000 to 1800 degrees Celsius and kept there for days or weeks. Almost all "tanzanite" gems sold today have a blue tint that has been created or increased by heating. A limited percentage of tanzanite on the market has a blue tint created spontaneously during metamorphism heat without any human intervention.

Some gemstone and jewellery consumers hold this naturally blue, natural tanzanite in high respect and search that out when purchasing. Tanzanite is known for its high trichroism, blue, violet, or burgundy based on crystal orientation. Tanzanite can also appear different depending on lighting circumstances. When viewed under fluorescent light, the blues are more visible, while when viewed in incandescent light, the violet colours are more visible. Tanzanite has coloured a reddish-brown to clear in its natural condition, and it needs a heating process to remove the brownish "veil" and reveal the stone's blue-violet colour.

Tanzanite- a pleochroism gem

The tanzanite stones are pleochroic. Pleochroism is a physical feature in which a material seems to be of multiple colours depending on which crystallographic direction it is seen from. When viewed from one way, tanzanite specimens can be a clear blue, whereas they can range from violet to reddish when viewed from another direction. This page's three photographs depict a tanzanite crystal from three different crystallographic perspectives. Tanzanite is a "trichroic" substance because each of the three directions has a distinctive colour. Pleochroism makes tanzanite cutting more difficult, but it also provides opportunities. The hue of a polished stone is determined by how the stone's table meets the crystalline axes in the rough. Tanzanite's most popular colour is a bright blue.

Cutters must evaluate each piece of rough to see if it can be cut so that the completed stone has the most face-up blue hue. If that's possible, they'll see if shifting the cut's direction will result in a larger stone of lower-quality hue that sells for a better price. Choosing how to cut tanzanite requires expertise, expertise, and a sense of price. Some highly experienced employees in the tanzanite cutting industry assess the rough and plan how it will be cut to enhance colour or value. The stone is then carved into a preform, which is a rough shape. It is at this point that value is acquired or lost. Every precious stone must be handled with care and a high level of skill.

What makes tanzanite stones popular among other blue gemstones?

Aquamarine, topaz, sapphire, and tanzanite are the four blue faceted gemstones most commonly encountered in commercial jewellery in the United States. Although they are all "blue," each one is distinct. Tanzanite is available in various tones and colour saturations that will appeal to practically any buyer who enjoys blue gemstones. The most precious Tanzanite gems are strong to brilliant blue, purplish blue, or violetish blue tint. These stones are substantially more expensive than stones of a lighter tint. On the other hand, many consumers like lighter-coloured stones and are willing to pay a lower price for them. Tanzanite stones comes in various blue tints, putting it up alongside sapphire, blue topaz, and aquamarine. Because many stones have a distinct touch of purple or violet, Tanzanite stands out in retail and chain shop jewellery displays.

Tanzanite is frequently noticed in a display case of blue stones by people who have experience gazing at gems and pay attention to colour. In the gem industry, tanzanite and sapphire are the two most popular blue stones. Because of its distinctive look and features, tanzanite is a gem that many people seek. Others buy tanzanite because it has a similar appearance to sapphire but at a far lower cost. Tanzanite is also up alongside lab-created sapphires, which are less expensive than genuine sapphires. In that case, some purchasers will choose tanzanite over a lab-created stone because they prefer natural stones to lab-created stones.

How to identify a real and fake Tanzanite ?

Testing a tanzanite is really a difficult task. There is no easy way to tell whether you have a natural tanzanite. The problem is there are gemstones that are kind duplicate to tanzanite and thus it become very difficult to identify a real tanzanite from fake tanzanite.

Look at the gem in natural and incandescent light from bulb. True tanzanite will display three colors as it is trichroic in natuure. If its a real tanzanite then it will show blue with a tinge of violet in natural light, but will also display flashes of pink and red when moved around in incandescent light.

Next if you look through the side of the stone, it should show the same intensity of color from the side as it does from the top.

You can also examine the stone through a 10X jeweler's loupe. This is required in most of the cases as tanzanite does not typically have falws that can be seen with the naked eyes. If you find no falws when it is viewed with the loupe, there is a good chance that it is not a tanzanite.

Lab created stones have no flaws than natural gemstones.

TIP- In order to buy real gems / gia certified tanzanite stones it is advised to buy from repuatable jewelers and keep your educated about the fair market value of a stone before you shop.

Before buying look for a jeweler who is a member of, or buys from - International Colored Gemstone Association.

The ICA works with about 90 % of tanzanite suppliers in sourcing their material and has a code of ethics.

IrisGems- one of the most popular GIA Certified Tanzanite supplier in USA

The royal blue colour is simply magnificent and is popular among a wide range of audience. We at Iris gems, the most trusted tanzanite supplier in the USA, help you provide a clear picture of the gemstones and wisely decide before investing in precious gemstones. We ensure the best quality and prices of gemstones. We provide you with GIA certified tanzanite  at IrisGems and offer you a never before seen collection, which is sure to blow your minds.


In today's gem and jewellery markets, tanzanite is one of the most popular coloured stones. That's surprising given that it was only found in the 1960s, whereas the other top-selling coloured stones have been known for centuries. It has a distinctive blue colour that is gaining in popularity as more people become aware of it. As colourful stones become more widespread in developing economies, their appeal is projected to expand. It is the only gemstone with such a little known supply that has an extensive and rising following.

Some FAQ's

Is Tanzanite a precious Gemstone?

A precious gemstone has all these 3 traits - beauty, durability and rarity. And tanzanite possesses all of these 3 qualities

What is the colour range of Precious Tanzanite Gemstones?

Tanzanite gems colours vary from rich, velvety blue to exotic violet. Once cut and polished the stone turn kaleidoscope of royal blue, violet, indigo, lilac and periwinkle shades. The more intense the colour, the rarer tanzanite it is and thus it is more expensive.

What is D block tanzanite?

It is the name of mine, the very fine tanzanite comes from famed D block mines. Block D is the area from which tanzanite material is mined. This doesn't mean that top grade tanzanite doesn't come from A, B and C blocks.

What is the hardness of a Tanzanite?

Tanzanite is a hydrous Calcium- Aluminium Silicate whose hardness is 6.5 - 7 on the Mosh Scale. ask for a copy of the certification. This will help in knowing the authenticity of a gemstone or this certification will clarify other doubts such as whether it has been examined genuinely at a reputed laboratory or not.

What is a gia certified tanzanite stones?

It is an analysis of stone quality, how authentic the stone is? GIA issues - Gem Identification Reports for tanzanite which is also know as gia certified tanzanite stones report. However, the GIA does not share grade reports for clarity, colour or cut.

Why do the tanzanite colour grades not reported in the GIA report?

This not implies to tanzanite, even GIA doesn't not other coloured gemstones report too. GIA believe that it is too hard to apply colour and clarity grades consistently across many varieties of coloured stones