Understanding Tanzanite Grading: The Key to Unlocking the Value of this Rare Gemstone
Tanzanite Grading: Understanding the Quality of this Rare Gemstone
Tanzanite is a rare and precious gemstone that has surged in popularity since its discovery in Tanzania in 1967. While it may not have the long history of other gems like diamonds, rubies, and sapphires, tanzanite’s stunning blue-violet color makes it a highly sought after stone for fine jewelry and luxury accessories. However, like any precious gemstone, the value of tanzanite depends on its quality and grading. In this post, we will explore how tanzanites are graded and what factors affect their value.
The Four Cs of Tanzanite Grading
Like diamonds, tanzanites are graded based on four criteria known as “the four Cs” – color, clarity, cut, and carat weight.
Color: The most important factor affecting the value of a tanzanite is its color. Tanzanites come in various shades ranging from pale blue to deep violet-blue with hints of red or purple. The most valuable stones have a vivid blue-violet hue that appears rich even under low light conditions. Stones with too much brown or grey undertones are considered lower quality.
Clarity: Clarity refers to the presence or absence of internal flaws (inclusions) or external blemishes (blemishes) on the surface of the stone. In general, high-quality tanzanites should be free from visible inclusions to the naked eye.
Cut: How well a tanzanite is cut affects both its beauty and value. A well-cut stone should maximize its brilliance while minimizing windowing (where light passes through without being reflected back). It should also enhance the natural color saturation while maintaining good proportions.
Carat Weight: Carat weight measures how heavy a gemstone is; one carat equals 0.2 grams. Generally speaking, larger tanzanites are rarer and more valuable than smaller ones. However, carat weight alone is not the most critical factor in determining a stone’s value.
Grading Systems Used for Tanzanites
There are different grading systems used to evaluate the quality of tanzanites. The most commonly used system is known as the “Tanzanian Grading System,” which grades stones from A (the rarest and most valuable) to D (the least valuable). Here’s how it works:
Grade A: These are the top-quality stones that have a vivid blue-violet color with no visible inclusions or blemishes. They are also well-cut and weigh over one carat.
Grade B: Stones in this category have good color with some slight inclusions, but they’re still eye-clean. They may be slightly less well-cut than Grade A stones or weigh under one carat.
Grade C: These stones have noticeable inclusions or blemishes that affect their appearance. They may also have weaker colors than higher-graded stones, making them less desirable.
Grade D: These are low-quality tanzanites that may have heavily included surfaces or weak colors. They’re often cut poorly and may weigh under 0.5 carats.
Another grading system used by some gemologists is the Gemological Institute of America’s (GIA) colored stone grading system, which assigns grades based on color, clarity, cut, and carat weight using a scale ranging from Excellent to Poor.
Factors That Influence Tanzanite Value
The demand for fine quality tanzanite has been steadily increasing over time due to its rarity and unique beauty. As such, several factors can influence its value:
Color Intensity: The more intense the blue-violet hue of a tanzanite is, the higher its value will be.
Clarity Level: In general, if a stone has fewer inclusions or blemishes, it will be more valuable.
Cut Quality: A well-cut tanzanite maximizes its natural beauty and can enhance its color.
Carat Weight: As mentioned earlier, larger stones are rarer and more valuable than smaller ones. However, the quality of the stone’s other factors (color, clarity, cut) may outweigh carat weight when determining overall value.
Origin: Tanzanites from certain mines may have a higher value due to their rarity or unique color characteristics. For example, tanzanites from the Merelani Hills mine often have a deeper blue hue that makes them more desirable to collectors.
Conclusion
Tanzanite is a beautiful gemstone with an interesting history and unique properties. Its grading system is similar to that used for diamonds but has some differences specific to tanzanite’s characteristics. Understanding how tanzanites are graded can help buyers make informed decisions about purchasing these rare gems while also ensuring they get good value for their investment. When shopping for tanzanites, keep in mind that high-quality stones should have vivid colors with no visible flaws and be well-cut regardless of their carat weight or origin.