GIA “Tanzanite Reports” – How to read one

The GIA (Gemological Institute of America) is the leading laboratory in the diamond and gemstone industry, and their reports are known for their consistency and accuracy. However, GIA colored stone reports are quite different from their diamond reports and do not offer the same details to consumers looking for tanzanite grading information. Below are some commonly asked questions about the GIA’s tanzanite reports.

Does the GIA issue Tanzanite Reports?

• The GIA issues “Gem Identification Reports” for tanzanite and other colored stones. These are in many ways different from their well-known diamond reports.

• The GIA offers full grading reports for diamonds only. The GIA does not grade tanzanite – or any other colored gemstone – for color, clarity, or cut.

• A GIA Gem ID Report assesses the characteristics of a colored gemstone (weight, measurements, shape, cutting style and color), specifies whether the gemstone is natural or synthetic, and indicates any detectable treatments.

• Unlike GIA diamond reports , GIA colored stone reports are not a guarantee of a colored gemstone’s quality and cannot be used as a basis for value.

• Unlike GIA diamond reports,  GIA colored stone reports never, ever, state the color grade, clarity or cut grades for a ruby, sapphire, tanzanite or any other colored stone.

What does a “GIA Tanzanite Report” look like?

This is an actual GIA Gem Identification Report for a 19.31 carat tanzanite.


Why are tanzanite color or clarity grade not noted in GIA reports?

It should be noted that the GIA has developed a system for grading the fine details of colored gemstones, which is taught to GIA Gemological Students and used worldwide by many Valuers and Gem Laboratories. However, the GIA itself does not use that system when issuing reports for tanzanite.

This is not limited to tanzanite: the GIA does not issue reports stating the color, cut or clarity grades of any colored gemstone. They believe it is too hard to apply color and clarity grades consistently across the many varieties of colored stones.

When reading a GIA report, a customer can expect to find information about the tanzanite’s basic body color: blue-violet or violet-blue; and a broad definition of its clarity: transparent, semi-transparent, or opaque. Further details, like depth of color (whether the stone is pastel colored or dark blue) or details of clarity (whether it has any eye-visible inclusions) are not noted. These broad terms can be extremely frustrating for consumers looking for more detail and reassurance regarding clarity or color grades.

Can I get a report which verifies unheated tanzanite?

There is currently no way of scientifically proving whether tanzanite was heated naturally underground by geological forces, or above ground by man after mining. The GIA – or any other leading laboratory – will never verify an “unheated” tanzanite.

I want to know how much my tanzanite is worth. Does GIA provide appraisals?

As an education and research institute, GIA does not provide gem or jewelry appraisals. The GIA is not involved in jewelry or gemstone pricing in any way. Through their laboratory reports, GIA provides an independent, objective opinion of a gemstone’s quality, and appraisers often refer to this information when determining the monetary value of a gem. Finally, while GIA may also provide the necessary gemological training to appraisers, the organization itself does not value or appraise gems or jewelry. If you would like an appraisal, you need to contact a Registered Valuer in your area.

Does the tanzanite from this store come with a GIA certificate?

GIA Gem Identification Reports are included in the purchase price for tanzanite stones weighing over 25.00 cts.
For stones or jewelry under 25.00 cts, a GIA Gem ID report can be ordered after purchase for $150.00 USD – please contact customer service to order a report.

In both cases, we will submit your tanzanite to the GIA for certification after purchase, which usually takes between 1-2 weeks.

Note: All loose tanzanite gemstones from Tanzanite Direct come with a full Gemological Certificate and Guarantee of Authenticity & Origin, completed by a qualified GIA trained Gemologist and a trained and registered Jewelry Valuer.

What gemological certification does loose tanzanite from Tanzanite Direct have?

All of our loose tanzanite gemstones are accompanied with a full gemological report, completed by our GIA trained Graduate Gemologist, Linda Kennedy. We use the GIA Colored Stone Grading System to grade our tanzanite.