WHAT IS TSAVORITE?

Tsavorite is actually a Green Grossularite Garnet. It is a Calcium Aluminum Silicate (like its sister stone, Tanzanite) with a chemical composition of Ca3Al2Si3O12. Its intense green hues are caused by the presence of Vanadium and sometimes Chromium. 

WHAT FACTORS SHOULD I CONSIDER WHEN JUDGING QUALITY IN TSAVORITE?

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.

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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:


A suite of top Tsavorites showing excellent saturation and tone levels

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

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 Grades Compared

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

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 among 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 loupe-clean to be considered top grade. 

VVS is the top grade in the GIA colored stone clarity grading system.  VVS stands for Very very slightly included and whilst some VVS Tsavorites are flawless / loupeclean they are still graded as VVS. In the GIA Diamond grading system they would be awarded a Flawless or Internally Flawless grade.

The ISG has written a great article on GIA Clarity Grading which may help you understand the subject further. 

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 a lot 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 2 decades. The graph below illustrates the value increase in pricing for the very top grades since 2004 for different size ranges.

Graph Showing Tsavorite Price Trajectory 2004 to 2020

OTHER CONSIDERATIONS

IS TSAVORITE A HARD GEMSTONE? : Yes, Tsavorite is 7 1/2 on the Mohs Scale and as such is considered a durable gemstone. It is often used in engagement rings for this reason, and Tsavorite Jewelry is featuring more and more on the world stage,

FAKES / SYNTHETICS / IMITATIONS : Tsavorite has never been synthesized (Lab created), 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.