This stone was represented as Topaz (imperial) but I was pretty sure the Imperial designation was incorrect still the color was what we were looking for. The RI comes up as 1.544 which was id'd by the performing gemologists as Quartz. Are there any other suspects? As always input is greatly appreciated. https://postimg.cc/gallery/JygFgDS
I think you're right! I didn't make the association when it was labelled "Quartz" because I didn't know the RI's but I found after posting that Citrine IS Quartz! Please forgive the brain fart...
I'm sorry to revive this thread but looking at this stone with a 10x loupe we noticed some parallel "graining" that was visible only through a certain axis and wondered if this is an inclusion and if it was more common in Citrine or Topaz. I found an example of the "graining" here... http://www.johnbetts-fineminerals.com/j ... inclusions
If the refractive index is accurate at 1.54 then it is quartz. The striations or needles your seeing can also be in quartz.
Thanks for the quick response. The thing is after talking to my wife who was with the "gemologist" when the test was done said she never saw him reset the refractometer after a previous test which we were pretty sure was quartz and the same jewelry store did make a mistake on a large Tanzanite labelling it "synthetic Corundum". We are looking for a decent lab closer than AGL to perform another test to satisfy the vendor prior to a refund. All that said the "better half" is also a better photographer so here is a pic showing the streaks/graining which disappears when the stone is shifted as in the above example.
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
One does not need to "re-set or re-calibrate" a refractometer.
Perhaps you are confusing the instrument with an unreliable REFLECTOMETER. The tanzanite being misidentified as syn. corundum illustrates that they are worthless tools.
Any gemologist worth his NaCl will (or should) have an actual refractometer for optical testing.
If this gemmo doesn't have one, I certainly would not personally trust their findings.
That is not what is depicted in your previous as striations, that looks more like color zoning. I may be wrong though.
Those lines correspond with striations similar to the ones in the previous link. They disappear in the same way the striations do when stone is shifted but are visible from opposite side of stone. Out of curiosity until I find an open lab does color zoning like this indicate anything of interest?
Joined: Tue Apr 05, 2016 7:58 pm Posts: 1424 Location: San Marcos, CA
Barbra is right and she is the expert here. I think you do not have much confidence in as well. If you visit the GIA website and research in the Gems and Gemology publication archives in the fall of 1986 edition on page 138, there is an image of an amethyst that I believe is what your seeing in your stone. Color zoning or banding. It's a interesting article as well to read. There is nothing interesting in it to me and actually degrades the value monetary wise.
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Hello again. For me the color zoning is a very good sign. Why? The great majority of citrine is heated amethyst. The majority of amethyst we see in the market today was made synthetically. Synthetic amethyst/citrine does not exhibit color zoning of this nature. Therefore your stone is likely an earth mined stone; not made in a lab. But I would bet dollars to donuts that the stone started out as an amethyst and was heated to turn it golden.
Below is a picture of similar color zoning in natural, earth-mined amethyst. Notice the similarities.
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zoning.jpg [ 59.88 KiB | Viewed 2880 times ]
Here is the article that glhays was referring to (and where I snatched the amethyst pic)
Just to clarify my confidence statement, it is not directed at Barbra but the person who gave you the R.I. test.
Gottcha! I took it in for a quick confirmation and it raised more questions. Unfortunately it looks like it will take a full blown ID to satisfy us AND the vendor to settle it once and for all ( I will say he agreed to pay for the report if it does turn out Citrine). As I said in OP we like the stone but not at the price point of topaz if it's Citrine. I really should have taken it to a lab from the get go but live and learn as they say! Thank you both for the input and I'll post the results. Barbra I think your bet is likely safe! Happy holidays and thanks again!
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