
GIA “Tanzanite Reports” – Do You Need One? And How To Read One
GIA Diamond Reports Are the Gold Standard.. (But Less so for Tanzanite)
For diamonds, GIA reports may be the gold (or even diamond!) standard. But you many surprised to learn that, for most people, a GIA report on tanzanite isn’t especially useful.
That's because the GIA Colored Stone reports are far less detailed than their reports on diamonds. So if you’re hoping to see a GIA report that guarantees your tanzanite’s color grade or clarity grade, you’ll be sorely disappointed, as the GIA does not provide these details for tanzanite—or in fact, for any colored gemstone.
This is frustrating because those are exactly the details most buyers want for peace of mind, especially when shopping online. In reality, the most practical thing such a report can confirm is whether the stone is genuine. Even then, with tanzanite, the risk of a fake is extremely low—unlike sapphire or ruby, there has never been a quality synthetic version of tanzanite created.
Still, let’s take a closer look at what a GIA certificate for tanzanite actually offers.
Does the GIA issue tanzanite reports?
Yes. The GIA issues Gem Identification Reports for tanzanite and other colored gemstones, but these differ significantly from their famous diamond reports.
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The GIA offers full grading reports for diamonds only. They do not grade tanzanite—or any other colored gemstone—for color, clarity, or cut.
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A GIA Gem ID Report lists a gemstone’s weight, measurements, shape, cutting style, and color, confirms if it is natural or synthetic, and notes any detectable treatments.
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Unlike GIA diamond reports, GIA colored stone reports are not a guarantee of quality and cannot be used as a basis for determining value.
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These reports never state color, clarity, or cut grades for tanzanite, ruby, sapphire, or any other colored stone.
What does a “GIA Tanzanite Report” look like?
A typical report includes the details above and might look like this example describing a lovely 10.92-carat tanzanite:
Why are color or clarity grades not noted?
The GIA has a grading system for colored gemstones, taught to gemology students and used worldwide by many labs and appraisers. However, GIA does not apply it in their official reports for tanzanite—or for any other colored stone—because they believe grading color and clarity consistently across such a wide range of gemstones is too challenging.
As a result, a GIA tanzanite report will only note:
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Basic body color: blue-violet or violet-blue
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General clarity: transparent, semi-transparent, or opaque
It also won’t say whether the color is pastel or deep, or whether there are inclusions visible to the eye—details that many buyers wish were included.
Can GIA verify “unheated” tanzanite?
No. There is no globally recognized scientific method to determine whether a tanzanite was heated naturally underground or artificially after mining. For this reason, GIA and other major laboratories will not certify a tanzanite as “unheated.”
Note: while the prestigious Gübelin Lab in Switzerland has conducted some research in this area, their approach has not been adopted by any other leading labs.
As a result, all tanzanite is generally assumed to have been heated in some way—but this does not affect its value. Unlike sapphire or ruby, where heating can significantly impact price, this is not a factor for tanzanite.
Does GIA provide appraisals?
No. The GIA is an education and research institute. They do not value or price gemstones and jewelry. Their reports simply describe the gemstone’s characteristics, and appraisers may use this information when determining value. If you want an appraisal, you’ll need to contact a registered appraiser.
Do Tanzanite Direct stones come with a GIA certificate?
No, but we can procure one for you on request, for a fee of $150 USD. After purchase, we will send the stone to GIA, with certification usually taking 1–2 weeks.
Note that all loose tanzanite gemstones from Tanzanite Direct do come with a full Gemological Certificate and Guarantee of Authenticity & Origin, issued by a GIA-trained gemologist and registered jewelry appraiser.
What certification do Tanzanite Direct stones have?
Every loose tanzanite gemstone from Tanzanite Direct is accompanied by a complete gemological report from our GIA Graduate Gemologist, Linda Kennedy. We use the GIA Colored Stone Grading System to assess color and clarity internally.