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.

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
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.

D - BLOCK TANZANITE

Looking to buy finest D Block Tanzanite? See our unparalleled D Block Investment Collection.

What is D Block Tanzanite? - Traditionally, the very finest Tanzanite comes from the famed D Block Mines. This is not to say that top grade stones don’t come from Blocks A,B and C but generally, the very finest material is mined in D Block. 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 have been found in block D and today, when the finest 1% is extremely hard to find, Block D still produces them albeit in much smaller quantities than in the past. We specialize in these rare pieces and buy almost exclusively from block D for our world renowned investment collection.

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

Lapigems Gem Company is a member of / staff hold qualifications from the following leading Gemological Organizations