Buyer's Guide
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.
Eye-visible inclusions decrease the value of tanzanite, particularly in lighter coloured stones, where they’re more visible against the gem’s body colour. Any inclusions that might pose durability problems - such as fractures - lower tanzanite value greatly.
Tanzanite is available as fine, larger pieces with strong colour or lighter material cut to standard sizes for use in mass market jewellery. Tanzanite colour is less saturated in smaller sizes. Gems must be above 5 cts. in size to have deep, fine colour.
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.
Questions & Answers
Is tanzanite tough enough for rings?
Tanzanite is not as tough as ruby and sapphire, but many people love their tanzanite rings. If you are active, consider a setting that protects the stone or choosing tanzanite for a ring you don’t wear every day.
Is predominately blue tanzanite rarer than violet?
Tanzanite shows different colours from different crystal directions. Because the blue colour is usually located on the short axis of the crystal, it’s often more difficult to cut a large, predominantly blue gem. Cutters have to decide whether to cut a larger, predominantly violet gem or a smaller blue one. As a result, tanzanites that face up blue are rarer than those that are predominantly violet.
Is there such a thing as pink or green tanzanite?
In rare cases, zoisite is found in pink, green and yellow. Although some refer to these colours as tanzanite, GIA calls them zoisite.
What’s AAA-quality tanzanite?
Although individual companies might create their own quality descriptions, like AAA, AA or A to denote the range of quality of their goods, no standard quality grading scales exist for tanzanite.
Does GIA grade tanzanite?
GIA doesn’t grade tanzanite. GIA Gemological Identification Reports assess the characteristics of a mounted or loose tanzanite (weight, measurements, shape, cutting style and colour), say whether it is natural or synthetic, and indicate any detectable treatments.
Find out more
Tanzanite: Questions & AnswersCaring for Your Tanzanite
Keep your tanzanite beautiful by following simple care and cleaning guidelines.
Durability
With proper care to avoid hard blows, tanzanite can be worn in all styles of jewellery.
Care and Cleaning
Warm soapy water is always safe.
Treatment
Other than heating, tanzanite is rarely treated, but might have fractures. Only clean fracture-filled gemstones with warm, soapy water.
