TANZANITE GRADING - THE FULL GUIDE

It is extremely important for a tanzanite gemstone to be expertly cut, as the cut impacts not only the brilliance and fire of your stone, but also the overall quality. A fine cut tanzanite will typically yield up to 30% premium over stones cut with weight maximization techniques. Cut is thus a very important factor to consider when purchasing tanzanite. A poorly cut tanzanite can make the best quality gemstone look inferior and often gemstones are cut to maximise their weight and not their beauty. All Shimansky Ayanda Queen of Tanzanite loose stones, as well as the stones set in tanzanite jewellery creations, are cut to perfection, ensuring the best quality tanzanite available.

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There are a few things to be aware of when looking at a tanzanite’s cut, the first of which, is windows. A window is a “dead” area in the middle of the gemstone which resembles a hole or empty space, as it has no light reflection. Windows come about when the stone is cut too shallow, or when it is cut too heavy in the back. Some tanzanite gemstones are cut with bulges in their pavilions to maximise the stone’s weight retention. This weight-saving technique ensures a larger carat weight, but has a negative impact on the cut grading, as a tanzanite cut for weight has to sacrifice some of its beauty. Even a tanzanite of beautiful colour can appear lifeless if it has been cut for weight preservation, making this a cutting technique best avoided.

An excellent cut ensures that the stone’s facets reflect light to create maximum brilliance and scintillation. To create an excellent cut, the angles on the table of the stone, and the angles of the pavilion of the stone must be perfectly proportioned and calibrated. When wearing your tanzanite ring or tanzanite necklace, you should notice a “bouncing” of light, or sparkling, with your movements. The more the gemstone sparkles, the better it has been cut. If tanzanite is cut too deep or too shallow, the radiance will deflect through the sides of the stone, thus limiting its brilliance. Depth percentage is calculated by dividing the depth of the stone by the stone’s girdle diameter. The ideal range is 60% to 80%.

Only fine cut stones are selected for Shimansky tanzanite jewellery creations. As such, Shimansky stocks only the best cut Ayanda tanzanite, and all tanzanite gemstones are graded for their cut as part of the certification process.

A tanzanite cutter spends a lot of time examining the rough stone to determine how it can be cut in an orientation that will yield the maximum face-up blue colour.

Good quality tanzanite has a deep royal blue or violet colour. Colours range from rich royal blues or vibrant violet to paler shades. The colour dominance depends on whether the gem is cut and polished from the long or the short axis of the crystal shaped rough tanzanite; and the more intense the colour the better the quality.

The depth of colour, or tone, in a tanzanite gemstone refers to the stone’s lightness or darkness and ranges from Intense (AAA+) to Faint (A). The saturation of the stone’s hue is often considered the most important factor when grading tanzanite. Saturation refers to the level to which colour “fills” the stone.

Clarity measures the incidence of natural inclusions found in a tanzanite stone. High clarity gives the stone added fire and brilliance, and the fewer the number of inclusions the more rare and valuable the tanzanite is. Significant inclusions have the potential of putting a gemstone’s structure at risk, as pressure on such a stone could result in a crack, and even breakage.

When it comes to colourful gemstones such as tanzanite, experts are most concerned that inclusions should not be visible to the naked eye. Though tanzanite gemstones are clarity graded in a manner similar to diamonds, less emphasis is placed the number of inclusions visible when viewed through a scope. With tanzanite, the most important thing, is that the gemstone is “eye clean,” meaning that flaws cannot be seen with the unaided eye. The Gemological Institute of America (GIA), classifies tanzanite as a Type I gemstone, which means it is usually flawless to the naked eye.

The location of the inclusion plays a significant part in the tanzanite’s clarity grading. An inclusion located in an inconspicuous place, such as near the stone’s girdle, will have less of an effect on the gemstone’s quality, than if the inclusion was located directly under the table facet. However, a significant inclusion located near the culet or corner of the gemstone, will put the gemstone at larger risk of breakage than an inclusion located deeper into the stone.

When selecting your tanzanite gemstone, be sure to understand your gemstone’s clarity grading, and ask the jeweller if you can look at the stone through a magnifying scope. It is important to be certain that your tanzanite does not contain a significant inclusion in a compromising area, and that it does not have any inclusions visible to the naked eye. Your tanzanite ring, or any other jewellery creation for that matter, will soon become a valuable heirloom to be passed down to future generations. Purchase yours from a reputable jeweller who will help you find the highest quality tanzanite gemstone to fit your budget.

In ancient times, before standard units of weight were implemented, diamond traders compared the size if diamonds to the seeds of the carob tree. Carob seeds had a uniform weight of 200 milligrams (one fifth of a gram), which they rarely deviated from. Hence, they determined the weight of the diamond. Though used for diamonds to begin with, carat weight is, today, the unit of measurement for all precious gemstones. The carob seeds were the start of the carat weight measurement, and today, state-of-the-art weighing mechanisms are used to determine a tanzanite’s carat weight.

The larger the tanzanite gemstone, the higher its value, and the higher its price. Large tanzanite gems are extremely rare, as larger crystals take much longer to grow. Large tanzanite gemstones over five carats generally have a deep blue or violet colour, which is more desirable than the paler lavender or medium blue colour associated with smaller tanzanite gems. Tanzanite weighing over 50 carats is deep blue in colour, and tanzanite weighing over 100 carats is dark blue-black in appearance. These large, dark coloured types of tanzanite are extremely rare and very sought-after by investors and collectors.

Similarly, two diamonds of equal carat weight could vary significantly in price if one were to have a higher cut, clarity or colour grading.

When selecting a tanzanite gemstone, it is important to find the perfect balance between all four Cs. A tanzanite gemstone with a big carat weight, but with poor colour or a poor cut, may very well be less valuable than a tanzanite with a smaller carat weight, but with excellent colour, clarity and cut. Carat weight plays an important role in your tanzanite’s value, but without support from the other Cs, “size” is not the most important factor. When purchasing a tanzanite ring, or tanzanite necklace in South Africa, be sure to ask for the certificate upon viewing the gemstone. This certificate ensures that the weight you are told in-store, is the actual weight of the tanzanite, recorded for your peace of mind.

The Shimansky Ayanda Queen of Tanzanite collection offers a wide variety of loose tanzanite stones and tanzanite jewellery creations in various carat weights. From delicate tanzanite rings to larger loose stones suitable for investment, Ayanda Queen of Tanzanite offers the finest hand-picked tanzanite straight from the Maasai tribe in Tanzania.

Extremely rare, tanzanite is only found in the Merelani Hills, a tanzanite mining area of about 4km, in Tanzania. About 16km south of the Kilimanjaro International Airport, the area lies at the base of Mount Kilimanjaro. As this is the only known source of tanzanite in the world, the gemstone is believed to be around a 1 000 times more rare than diamonds, making it extremely sought-after.

When buying tanzanite in South Africa, be sure to select a reputable jeweller that is able to provide certification for your tanzanite gemstone, and who has a strong reputation for dealing ethically in gemstones. Your tanzanite jewellery creation will become a precious heirloom to be enjoyed for many generations to come. Knowing that it was sourced ethically and conflict-free ensures a peace of mind, and appreciation for your beautiful tanzanite jewellery creation, for years to come.