GIA GEMOLOGIST ARTICLE

The Definitive Tsavorite Buying Guide

As with all gemstones, Tsavorite quality is defined by a number of factors. This article looks at these in detail and tell you all you need to know.

Antony Zagoritis

GIA Graduate Gemologist
ICA Ambassador to Kenya


  • When purchasing Tsavorite there are several factors you need to consider in order to judge quality - these are the 4 c's - Color, Clarity, Carat Weight and Cut.

    TSAVORITE COLOR

    Color is the most important of the 4 C's when considering Tsavorite 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. Also, Tsavorite has a variety of colors which are considered top and this can be confusing most especially when trying to make comparisons. We have tried to help make this clearer by displaying a suite of Tsavorites below demonstrating color quality:

    Tsavorite top grade.jpg
    A suite of top Tsavorites showing excellent saturation and tone levelsTsavorite color light.jpg

    A suite of low grade Tsavorites showing low saturation and tone levelsTsavorite too dark.jpg

    A suite of low grade Tsavorites showing over saturation and tone levels

    From the above images it is clear how the top colors show how a top level of saturation of color produces a vivid deep color and when combined with top levels of tone produce a beautiful gemstone.
      
    The other pictures indicate what happens when the color is desaturated or oversaturated and have high tone levels.

    The GIA Color Grading System

    The GIA color grading system is the most widely accepted color grading system for colored stones and was developed around grading saturation and tone levels. It is still the most widely used system in the trade and one of the only ones with a solid scientific basis. 

    The chart below demonstrates how tone and saturation combine in this system:

    GIA Tsavorite Color Chart.jpg


    GIA Grades Compared

    The table below demonstrates quality categories and how they relate to GIA grades:

     

    GIA GRADES CONSIDERED 

    TOP QUALITY

    GIA GRADES CONSIDERED 

    TOO LIGHT

    GIA GRADES CONSIDERED 

    TOO DARK

     

    Tone & Saturation
    levels of

    6/6, 6/5, 5/5


     

    Tone & Saturation
    levels of

    5/4, 4/4, 4/3, 3/3, 3/2

     

    Tone & Saturation Levels of

    7/6, 7/7


    Hence, the finest Tsavorites have tones in the 5-6 range and saturations in the 5-6 range so if you are looking for the finest stones these are the grades you want to look out for.



    CLARITY

    Clarity is the second most important of the 4 c's when considering Tsavorite 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. Tsavorite is classed as a Type 2 gemstone by the GIA and as such is grouped amongst stones regarded as "usually included". This means that because of Tsavorite's geology, the majority of stones have some inclusions. Unlike Tanzanite, which is a Type 1 gem, it is not essential that it is loupeclean.  Below is a chart showing the GIA clarity grading system.

    VVS : This is the top grade in the GIA system. Tsavorite is classed by the GIA as a "Type 2" gem which means it is graded less strictly than Type 1 gems like Tanzanite but more strctly than Type 3 gems like Emerald. VVS Stands for Very very slightly included and whilst many VVS Tsavorites are loupeclean they can contain minor inclusions classed as somewhat easy to see with a loupe (10x magnification) and usually invisible to the unaided eye. Typical minor inclusions may be small included crystals, fine needles, liquid inclusions (known as fingerprints), tiny feathers.


    VS : This stands for Very Slightly Included and these stones are characterised by noticeable inclusions of moderate size which are easy to see under 10x magnification and sometimes visible to the unaided eye. Typical inclusions may be liquid inclusions, needles, small feathers, small chips.


    SI1 - SI2 : This stands for Slightly Included and these stones are characterised by obvious inclusions which are large and/or numerous under 10x magnification. In SI1 they are apparent and SI2 very apparent to the unaided eye. Typical inclusions are large included crystals, large liquid inclusions, feathers, dense clouds. As a rule, if you can see inclusions in the photograph displayed on gem sites (such as in those displayed below) then the stone is most likely an SI or lower.


     


    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.



    CARAT WEIGHT


    Tsavorites are not generally available in large sizes. even 1 carat fine stones are rare. On average, it takes over 1 ton of gem bearing rock to extract under 5 carats of fine 1 carat pieces. Fine stones over 2 carats are rare and over 3 carats they become very rare in the fine qualities. Many stones are cut to retain weight and sacrifice quality for size so be careful when buying large stones that you are not buying simply for size and that the clarity and color are also fine. Carat weight affects the price generally as weight increases stones in the same quality bracket will cost more per carat. In Tsavorite, because of the huge rarity of large stones, this price jump is marked.



    CUT

    Although it has the least impact on value of the 4 C's cut is still important. In the market, Tsavorites 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. 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.


    TSAVORITE PRICES

    Tsavorite prices have shown a steady upward trend for the past decade. The graph below illustrates the value increase in pricing for 2-5 carat stones since 2010.

    Graph

    Price per carat : Tsavorite has a much larger increase in price per carat as carat weight increases compared to most other colored stones. 



    OTHER CONSIDERATIONS


    FAKES / SYNTHETICS / IMITATIONS : Tsavorite has never been synthesized, but a number of imitations exist. The most common is green glass. Another is synthetic Spinel (a manmade imitation) Laymen can easily be fooled so always buy from a reputable dealer, preferably a member of the ICA (International Gemstone Dealers Association) which has a strict code of ethics.


    ENHANCEMENTS : None. Tsavorite is one of the most "honest" of all gems on the market today. It is simply cut, there are no treatments, enhancements or synthetics. It is one of the most endearing features of this wonderful gemstone.


    WHAT IS KURANZE TSAVORITE? : There are a number of Tsavorite mines in East Africa. The majority of deposits contain Tsavorite colored by Vanadium. However, one deposit, in a place called Kuranze, also contains Chromium. This gives the stones from this deposit exceptional color, often with a trace of blue in the green like the finest Muzo Columbian Emerald. This mine does not produce many stones and most that it does produce are small but material from this deposit is considered a cut above the rest.




IS TSAVORITE A GOOD INVESTMENT?

The short answer is "Yes". Tsavorite prices have been on a steady upward trajectory for decades now and the past decade particularly, has seen substantial price growth. The Financial Times article entitled "Tsavorite Connoisseurs spot the value of the rare green gem" touches on the stone's potential.

ABOUT THE AUTHOR Antony Zagoritis, Bsc, GG

Antony completed his GG (Graduate Gemologist) in 1998 at the Gemological Institute of America in California after a degree a Business at the University of Bath, in England. He has extensive experience in the colored gemstone trade with over 20 years buying rough at the source. He is currently the Ambassador to Kenya for the ICA (International Colored Gemstone Association) in New York which is the worldwide body for colored gemstones.

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