Can Someone Identify This Stone? Maybe Tanzanite?

I purchased 4 gemstones from an auction house that I have never seen before. After some research online, I “think” it might be Tanzanite but would be grateful if someone could tell me for sure. The gems appear mostly blue but when you look at them from another angle they appear as having alot of purple and yellow/green colors to them. I have attached an image of the stones.

If, my suspicion is correct and they are Tanzanite, what price range would they go for retail? The larger oval is 6.63 carats, the second oval is 2.80 carats and the other two are 2-4 carats each. I saw some similar stones online that were about 5-7 carats each and sold for $6,000.00 but on the other end I had one person tell me they were not worth much Hmmm!!

Any information would be a huge help to me at this point! Thanks.

These are very pretty. Couldn’t you just pay the $85 for GIA to do an identification? Seems like it would be money well spent if there’s a chance they are tanzanite.

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I thought about doing just that but was discouraged when a jeweler told me it would probably be a waste of time since he felt the stones were nothing more than “low quality” tanzanite!! But I think I will go ahead and send them to GIA anyway.

Thanks for your reply!

If you do get an ID report, please let us know what you find out. I’m curious to know what stone could be so pretty if not tanzanite! :slight_smile:

Hi abrugger- I decided to send the stones to GIA for identification even though all my research points toward the stones being Tanzanite. I will let you know what the results are once I receive them. Thanks

These are better images of the stones…

Hi abrugger- I had the two oval stones tested by a gemologist and he confirmed them as (Zoisite) Tanzanite. So my suspicions were correct for those two stones. I didn’t get the other two greenish-blue-grey stones tested but I think they are just low-quality Tanzanite. Just thought I would let you know! Thanks.

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I’m excited for you and what a great auction find! Thanks for sharing your results!

Hi, just thought I would throw my 2 cents worth in, in regard to the greenish, blue, grey gems that you suggest may be low grade.
natural unheated tanzanite is trichroic and have similar colours, I would suggest that these are probably natural unheated tanzanite.
nothing low grade about that, so you can keep them as is or try and find someone who knows what they are doing and have them heat treated.


Hi, Here’s my guess (emphasis on guess). i have several stones I picked up on a TV gem shoe. They called them Ocean or Seafoam Tanzanite. Yes, they were worth less than the blue, but there is a market for them. Good luck. They are worth something!

I agree with Lynne
I have a couple greenish blues
not so much of a red flash as older tanzanite
I personally really like these ocean Tanzanites
when I bought mine it was labeled bi color zoisite
but that is what they look like

In regard to heat treating tanzanite, unheated stones are trichroic and heated ones are dichroic. Also, heat treating usually results in stones which have the brown removed, but are lighter rather than darker. I understand that most of the good tanzanite coming out of the mines presently is “diesel” which is a deep brown color. When the brown is removed by heat treating, the blue is left. While there are better ways to do it, often the rough is treated in aluminum foil over a propane cook stove, locally. I don’t think heating the stones under discussion is going to result in a better color.

Hi my father used to heat treat tanzanite in our back yard with a small wood fire for several hours in a crudely made crucible with an inert powder substance to pack the tanzanite in, worked quite well. Although in saying that I tried once with heat beads in a crucible and put a blower on the heat beads to get more heat. guess what the Tanzanite blew up and I had a lot of small pieces left. Just a warning to those who may want to try to heat treat Tanzanite and softer gemstones.

It’s hard to determine a stone from a picture but these looks like spinel

While it is impossible to say with 100% certainty from a photo alone, my opinion is natural unheated bi-color zoisite aka Tanzanite.

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Dear Chris

I accept your apology. Feel free i was not offended i just wanted to answer to your concern.

Hi I do not know much about Tanzanite , but i have seen stones like these in the last few weeks on Ebay ( ya I know ) going at action for over 2k . Same cut style and size.Let us hope these are real bids not just shills, just to run up the price in the market. But it feels to me like their may be a lot of this size materiel out there being put on the market.some one is selling their non investment med level stock now the prices are up . Ps this is not to say the stones you bought are not a good buy. Just my opinion of the market.

707chrisa, the stones which are shown are from Tanzania. they are real. When you want please let us talk.
Thank you.

Sorry every one I did not wish to sound critical of any of the stones posted in this thread .