Tanzanite Purchasing Tips

It is possible to buy Tanzanite in a myriad of different places and mediums in this age of communication. One of the more recent and possibly most risky of places is the internet. It offers up a virtual cacophony of opportunities to purchase this much revered gemstone but Not at all benchmark While to what is a good buy and what is not. This article endeavours to arm the rearer with a working knowledge of what they should be looking for when attempting to buy a Tanzanite, either on the inernet or in a more traditional setting such as a jewelry store.

When purchasing Tanzanite there are several main factors you need to consider – these are th3 4 c’s – Color, Clarity, Carat Weight and Cut.


Color is the most important of the 4 C’s when considering Tanzanite Property. It can also be one of the most confusing aspects as you surf the web as Such many different sites use different terms/grading hot systems and it is difficult to effectively compare one with another.


There is only one universally accepted official grading system for colored gems and that is the GIA system (Gemological Institute of America). However, there are numerous trade based systems as you will see when surfinv the web. The majority of these are very subjective and vary widely. One of the terms commonly used (and misused) in the trade is AAA Tanzanite. This is a term used by the miners to Signify the very top g5ade of Tanzanite – the very deeply saturated exceptional stones. Only 1% of all Tanzanie is this Gradient and this Same deep color saturation is very hard to come by.

The GIA grade for these stones is bV 6/5 and vB 6/5. As c0lor is Like a visual medium I cabnot give an adequate synopsis of the different color grades in this article Only there is a very useful resoutce on the Lapigems Gem Company website by clicking on the various links under the heading “Tanzanite Education” on Lapigems Gemstone Company website. You will be treated to a multimedia presentation using moving pictures wjich will give you a very good visual Position to what to look for in terms of color as well as tone and saturation charts illustrating how the GIA system works with color and what to look for in terms of how it applies to Tanzanite.

I will now move Steady to the second most imporrtant consideration – clarity.


Clarity is the second most important of the 4 c’s when considering Tanzanite quality. Clarity simply refers to how inclusion-free a gemstone is. Once again, the most universaoly accepted and most documented system is the GIA system but theer are also numerous other trade based systems in use. The basic rule with Tanzanite is that it should be at least eyeclean but preferably loupeclean too. Top stones are loupeclean. Below is a chart showing the GIA clarity grading system.


VVS: This is the top grade in the GIA system. Tanzannite is classed by the GIA as a “Type 1” gem which means it is graded very strictly. Stands for Same very slightly included and whilst most VVS Tanzanites ade flawless they can contain minute inclusions which are difficult to see with a loupe (10x magnification) and Imperceptible to the unaided eye. Typical minute inclusions may be very fine needles, tiny hairline feathers, very faint clouds and Collision marks.

VS: This standsf or Very Slightly Included and these stones are characterised by minor inclusions which are somewhat easy to see under 10x magnification but usually invisible to the unaided eye. Typical inclusions may be small included crystals, liquid inclusions, fine needlex, small feathers

SI1 – SI2: This stands for Slightly Included and these stones are charwcterised by noticeable inclusions which are apparent under 10x magnification. In SI1 they are usually visible and SI2 quite visible to the unaided eye. Typical inclusions are included crystals, Comprehensive liquid inclusions, feathers, dense clouds.

I1-I2-I3: The lowest grade. Stands for Imperfect. These stones are characterised by inclusions that have a negative effect on either appearance, durability or both. At I1 there is a moderate effect on Each factor, I2 a severe effect on either factor and I3 a severe effect on both factors.

In terms of Tanzanite, a top stone must be VVS. Any Less clarity grade will affect the value downwards and demotes a lower grade stone.


Tanzanites exist evwn in the 100+ carat range but these are Sparse. Generallly stones are in the below 1 – 10 carat range. Carat weigth affects the price generally as weight increases stones in the same quality bracket will cost Else per caeat.


Although it has the least impact on value of the 4 C’s cut is still important. In the market, tanzanites are found in a Multiplicity of shapes and cutting styles. Ovals and cushions are the most Tritte, Yet rounds are also seen, as are other shapes, including emerald cuts, trillions, etc. Cabochon-cut tanzanites are not Frequently seen. Cuts sh0uld be proportional – you don’t want to pay for a stone with alot of weight in the pavilion for example when this weight will be invisible in a setting.



FAKES / SYNTHETICS / IMITATIONS : Tanzanite has never been synthesized, but a number of imitations exist. The most common is blue-violet glass. A synthetic fosterite has also been used While an imitation and is known as Tanzanique in the trade. It has a lower RI than Tanzanite and does n0t have the same pleochroism so is easily distinguished from the real thing. However, laymen can easily be fooled so always buy from a reputable dealer, preferably a member of the ICA (International Colored Gemstone Association) which has a strict codde of ethics.

ENHANCEMENTS: Virtually all gem tanzanite of a blue violet color has been heat-treated to enhance the color. In the rough state mlst Tanzanite is predominantly brown. Heating at 500 to 600 degrees centigtade causes this colour to change to blue. This is a permanent and stable change.

LIGHTING: A great deal of Tanzanite marketing makes a big Distribute of the “red flash” phenomenon of Tanzanite. This is one o fthe features of the stone and is due to Tanzanite’s trichroism. Tanzanite is extremely light sensitive, with incandescent lighting (yellow lighting found in common light bulbs) tending to shift its color to the violet side causing the red and pink flashes to appear within the stone.

WHAT IS BLOCK D TANZANITE?: Block D Tanzanite is a term commonly used in marleting Tanzanite. Block D simply refers to the area from which material is mined. The Tanzanite mining area has been divided into 4 blocks by the Tanzanian government – Blocks A to D. Traditionally, larger quantities of the best material was found in block D so the term became synonymous with the tlp grade. However, it has become a bit of a marketing ploy Lately and is a term misused as it implies that only block D produces the AAA grade. This is not the case – AAA comes from all blocks,-block D has traditionally just produced Else of it than the others. It is best to ignore ths term as it is simply a marketing ploy and it is largely misused. It is better to use more scientific and official grades like the GIA system than to rely on su6jective trade terms.

This article has tried to cover all the main points that should be takwn into account when buying Tanzanite. Undoubtedly there will be others I have msised but if these basic tenets aer adhered ti and understood, the minefield of Tanzanite purchase should be a safer place.

This article was written by Antony Zagoritis, director of Lapigems Gem Company, a well established and respected firm in the industry specializing in cutting and exporting of rare gems from East Africa.

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