Several factors contribute to determining the value of tanzanite. The following characteristics are generally considered important in assessing the value of tanzanite:
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Color: The most valuable tanzanite displays a vibrant, intense blue-violet color. Gems with a medium to dark tone, vivid saturation, and strong saturation of blue and violet hues are highly sought after. Stones with a rich and saturated color are typically more valuable than lighter or less saturated ones.
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Clarity: Tanzanite with higher clarity grades, meaning fewer visible inclusions or blemishes, is generally more valuable. However, it's important to note that tanzanite commonly contains inclusions, and some are more acceptable within the gemstone's grading standards. Eye-clean or slightly included stones are usually considered desirable.
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Carat weight: Larger tanzanite gemstones are rarer, and their prices increase exponentially with size. As a result, larger tanzanite specimens tend to command higher prices, assuming the other quality factors are also favorable.
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Cut and Shape: Well-cut tanzanite gemstones that maximize their brilliance and color are valued more than poorly cut stones. Precise faceting and appropriate proportions ensure optimal light reflection and overall visual appeal. The shape of the tanzanite, such as oval, round, emerald, or pear, can also impact its value based on market preferences.
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Origin and Rarity: Tanzanite sourced from the original mining area near Mount Kilimanjaro in Tanzania is typically considered more valuable due to its authenticity and association with the gem's discovery. Additionally, tanzanite is a relatively rare gemstone, and as the known deposits near the mining area are projected to deplete in the coming decades, its rarity adds to its value.
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Treatment: Most tanzanite undergoes heat treatment to enhance its color and improve its appearance. Heat-treated tanzanite is widely accepted and does not significantly affect its value. However, unheated or untreated tanzanite, particularly those with exceptional color and clarity, can command a premium.
It's important to note that these factors interact with one another, and the overall balance of color, clarity, size, and cut determines the value of a specific tanzanite gemstone. When assessing the value of a tanzanite, considering these factors in conjunction with market demand and prevailing prices will help determine its worth.