Fine tanzanite’s strong pleochroism and intense violet-to-blue face up colours help identify the gem and provide a large part of its value. Paler colours 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 coloured 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.
Tanzanite Quality Factors: The Comprehensive Guide
Tips & Advice
1. Size and colour are related.
Tanzanite usually has to be larger than five carats to reach a deep saturated violetish blue or bluish violet colour. Small accent stones of less than two carats in size are commonly a lighter colour.
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 jeweller.
Because tanzanite is an unusual gem, make sure you choose a jeweller who has gemmological knowledge and expertise. A jeweller who knows and loves tanzanite should have a selection to show you so you can see quality differences side by side.