Fine tanzanite’s strong pleochroism and intense violet-to-blue face up colors help identify the gem and provide a large part of its value. Paler colors are more commonly found and less valued. Eye visible inclusions also cause a drop in value.
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What To Look For
Due to tanzanite’s strong pleochroism, each fashioned gemstone usually displays a mix of both blue and violet hues depending on viewing angle. The majority of tanzanites mined are light to medium purple and blue colored stones. However, the gem is generally famed for the small number of intensely saturated, bluish-violet stones which usually occur in sizes above 5 carats.
Eye-visible inclusions decrease the value of tanzanite, particularly in lighter colored stones, where they’re more visible against the gem’s bodycolor. Any inclusions that might pose durability problems—such as fractures—lower tanzanite value greatly.
Tanzanite is available as fine, larger pieces with strong color or lighter material cut to standard sizes for use in mass market jewelry. Tanzanite color is less saturated in smaller sizes. Gems must be above 5-cts. in size to have deep, fine color.
Tanzanite Quality Factors: The Comprehensive Guide
Tips & Advice
1. Size and color are related.
Tanzanite usually has to be larger than five carats to reach a deep saturated violetish blue or bluish violet color. Small accent stones less than two carats in size are commonly a lighter color.
2. Consider a protective setting.
With a hardness of 6 to 7, tanzanite is softer than many gems. Exercise a little caution with tanzanite rings. A setting that surrounds the tanzanite with metal or gems will help protect it.
3. Don’t compromise on cut.
The quality of the cut can make a big difference in beauty and brilliance. Your tanzanite should sparkle in a lively way, reflecting light back evenly across the entire gem. Poorly cut gems are much less marketable and sell at a discount.
4. Work with a knowledgeable jeweler.
Because tanzanite is an unusual gem, make sure you choose a jeweler who has gemological knowledge and expertise. A jeweler who knows and loves tanzanite should have a selection to show you so you can see quality differences side by side.