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TANZANITE 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 universally accepted and most documented system is the GIA system but there 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. Tanzanite is classed by the GIA as a "Type 1" gem which means it is graded very strictly. Stands for Very very slightly included and whilst most VVS Tanzanites are flawless they can contain minute inclusions which are difficult to see with a loupe (10x magnification) and invisible to the unaided eye. Typical minute inclusions may be very fine needles, tiny hairline feathers, very faint clouds and percussion marks.
VS : This stands for 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 needles, small feathers
SI1 - SI2 : This stands for Slightly Included and these stones are characterised 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, large 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 either 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 lesser clarity grade will affect the value downwards and denotes a lower grade stone.
MORE TANZANITE INFORMATION
The 4 C's of Tanzanite
Tanzanite History & Care
Tanzanite FAQ's
You may also like to read more about Tanzanite on the ICA website. The ICA (International Colored Gemstone Association) is a non profit institution dedicated to educating the public about colored gems. It has a strict code of ethics.Our company has been a member for many years.
Or alternatively we can offer some select AAA Tanzanite for discerning buyers:
Buy AAA Tanzanites from our private collection
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TANZANITE GUIDE
When purchasing Tanzanite there are several factors you need to consider - these are the 4 c's - Color, Clarity, Carat Weight and Cut.
TANZANITE COLOR
Color is the most important of the 4 C's when considering Tanzanite quality. It can also be one of the most confusing aspects as you surf the web as so many different sites use different terms/grading systems and it is difficult to effectively compare one with another.
COLOR GRADING SYSTEM FOR TANZANITE
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 surfing 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 denote the very top grade of Tanzanite - the very deeply saturated exceptional stones.
Below is a suite of Tanzanite loosely representing the color grades as they descend. We have used the GIA system but included some of the other trade grades often used to help with comparison purposes.Of course there are many other colors which fit in between these but it serves as good basic guide to color.
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GIA GRADE
bV 6/5 or vB 6/5 |
GIA GRADE
bV 6/4 or vB 6/4 or bV 5/5 or bV 5/5 |
GIA GRADE
bV 4/4 or vB 4/4 or bV 5/3 or vB 5/3 |
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OTHERS
AAAA
AAA
vB 1+
bV 1+
Investment Grade
Exceptional
Vivid Exceptional |
OTHERS
A
AA
vB 1
Fine |
OTHERS
B
vB 2
bV 2
Fancy 1 |
Click here for a chart showing Tone and Saturation levels in Tanzanite
TANZANITE CONSUMER PROTECTION NOTE
Whilst many sites proclaim to be selling AAA stones from Block D, most are actually dealing in the A range. Prices are considerably lower for this material and it has become a marketing ploy to represent lower cost material as AAA (bV 6/5 vB 6/5) at low prices. True block D AAA material is very rare and difficult to get. Less than 1% of all Tanzanite production is true AAA and it is considered exceptional. It is thus at a premium price right from the mouth of the mine to the very few highly selective and high end jewelers who have access to it. Beware of sites offering this exceptional material at prices too good to be true. Chances are you will be buyng a grade to several grades lower. This is fine as even lower grade Tanzanite is very beautiful, but it shouldn't be misrepresented as AAA.
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CARAT WEIGHT
Tanzanites exist even in the 100+ carat range but these are rare. Generally stones are in the below 1 - 10 carat range. Carat weight affects the price generally as weight increases stones in the same quality bracket will cost more per carat.
CUT AND TANZANITE
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 variety of shapes and cutting styles. Ovals and cushions are the most common, but rounds are also seen, as are other shapes, including emerald cuts, trillions, etc. Cabochon-cut tanzanites are not often seen. Cuts should 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.
OTHER CONSIDERATIONS FOR TANZANITE
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 as an imitation and is known as Tanzanique in the trade. It has a lower RI than Tanzanite and does not 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 code of ethics.
ENHANCEMENTS : Virtually all gem tanzanite of a blue violet color has been heat-treated to enhance the color. In the rough state most Tanzanite is predominantly brown. Heating at 500 to 600 degrees centigrade causes this color to change to blue. This is a permanent and stable change.
LIGHTING : A great deal of Tanzanite marketing makes a big deal of the "red flash" phenomenon of Tanzanite. This is one of the 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. The 2 images below of the same stone show it under white (daylight) and under incandescent light:
Under white light |
Under incandescent light |
WHAT IS BLOCK D TANZANITE? : Block D Tanzanite is a term commonly used in marketing 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 top grade. However, it has become a bit of a marketing ploy recently 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 more of it than the others. It is best to ignore the 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 subjective trade terms.
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