I can't believe what the IGS did

So I mentioned in my last post that I had won one of the Garnets in the promotion drawing that they just did. I s[date=2024-03-09 timezone=“America/Los_Angeles”]tated I would let you guys know what showed up because I really did not know what to inspect. Well I opened the mail today and there it was

When I read the card I was shocked. I never thought they would send a color change garnet I have school and a very busy week so I haven’t had time to run it through it’s paces under every kind of light source.So I will and post the pictures when I have some free time.but until then I’m curious to see if anyone can guess what colors it will produce under what types of light. Or if anyone recognizes what type it is called in the industry like for example purple to Green color change Garnett. And if anyone from the iGS comes across this thank you guys for everything I’ve learned so much off of the community and you guys as well the knowledge in your courses and everything you produce especially your price guide is the industry standard for the United States but I know I don’t have to tell you guys that
Thank you,
John Buchan


Congrats John!

Looking forward to seeing the measurements and research on the stone… it looks really nice!


I’m betting red and green as the color change. I could be wrong but I just purchased some color change garnet and that’s what it changes to. It also might be red and purple or pink. Looking forward to learning what it really does.

Congratulations on your win from IGS. I am looking forward to finding out what all the gemstones that I have won through various auctions and sales ARE, and are worth. Some have been certified, but most (over 350) have not. Again, congratulations on your win. L.W.McQueary / oldtroll57@gmail.com /

My guess it goes from a red in incandescent, to a rich purple in LED or fluorescent?

So I appreciate all the guessing some of the colors I’ve observed have been mentioned so I think it’s time for a hit as well as a little bit of education that I have learned from receiving this gift the picture was supposed to be informative if you paid enough attention the picture is in front of a window that has direct sunlight coming in when I first opened the envelope that contain ed the jam I assumed it was an ordinary almondine and pyrope garnet and then my jaw dropped when I read the card and seen that it stated it was a color changing Garnett first thing I did was grab my cheap gem light I’m sure we all have one it has all led type lights it is double sided one side has a white light yellow light and a blue light the other one has a uv in the 365 & 395range but no filter so it’s not that great of a uv as well as a red light. So normally I use it I check most gems just in case they have a color change property normally you’ll see some kind of change between the White and the yellow type light it’s basically simulating a 65k daylight light and then a warm approximately 27k light. When I did this I didn’t see much of a change so I started checking a couple other sources I have a box I built that has a transformer on it that can produce an actual light source at the flick of a switch that is 65k, 60k, 55k, 47k, 34k, 30k,and27k so I placed it in a box ran through all the different options seen a little bit of change but nothing that I would consider a color change so I held it up to the window real quick didn’t change any color that could be centered more than a color s*** a color change I believe is described as two spaces in the color wheel so put it in a standard 1" round clear gem container w/weight foam then went in to out side to abserve it in direct sunlight while I pointed what it was exactly as well as look at the cut as and polish so after assessing the cut with a loop I noted the cut and polish where executed with very high persitioin but it had a shorter crown than most faceting diagrams recommend for cuts I have done similar possibly identical so I put my loop down to see the :fire: this mod to the cut produced to my surprise I could no longer see through the stone it Had slowly become almost black & opaque so there’s I think I’d consider those more than hints because you now have the information that I do except to take the picture for this formI put it in a dark space like an envelope and then put it up to the window with direct sunlight waited till it was changing and almost done and took the picture this weekend I will post pictures of it in every light source that I can if you read about color changing Garnett’s a lot of people believe them to be one of the most spectacular color changing gems cuz of the fact a lot of them seem to have a property where they shift or change in multiple sources of light I’m curious to see what else it produces hopefully you are too I encourage everyone to keep guessing this Stone taught me so far a huge lesson I read an article in the IGS about stones with similar properties they take a while to change they can be affected by temperature light sources excedera but it’s nothing close to instantaneous when I read the IGS article about this reaction I checked a couple of stones in my inventory it it’s hard to remember the color they originated as before I tested them for half an hour and then recheck them at the end so I would suggest if you test after reading the article take a picture before you run the test and then take a picture after so you have comparison.

If anyone knows the name of the article please post it so people can check it out thanks :+1:

Dang what are winning over 350+ stones from
And what’s the best one you’ve ever won not highest value your personal favorite and can you post a pic I will e to see your baby

Everyone post a pic of you favorite gem value not considered it can be anything uncut cabed ex. I want to see your baby and why is it your baby?

Unheated Tanzanite Crystal
13.44g (67.2ct)
27 x 27 x 12mm (at base)

It’s not easy finding blue tanzanite rough that has not been heat treated. This crystal displays the green tint along with the blue and a deep purple when viewed through the side. It’s definitely one of my favorites… :grin:

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The over 350 stones are NOT from one place or at one time. They were acquired “winning by the highest bid” at several auctions over the past 10 years, mainly estate auctions. Some were group (varying lots of stones from 2 to 30), some were individual stones, from internet gemstone auctions. None were contest or sweepstakes won. As an amateur collector, I have only had the funds to be able to have 13 certified. Have not sold any as of yet, but have considered it to finance getting others certified.


My wife loves watching the estate auctions for jewelry and gems we’ve never gotten screwed except for recently we bid on a emerald a Sapphire and Ruby the pictures look great when they got here the Ruby either wasn’t a ruby or it was so filled with glass that it was not reading as a ruby it was so fractured that I couldn’t even tell if it started its life is corundum this Sapphire was better but definitely misrepresented in the pictures it was dark so it did better than the translucent Ruby supposedly and then we bought an emerald these were all at the same time from the same auction and we brought from this auction house multiple times they always use it thermal conductor to show you the reading on the stones this time none of them read the exact same as theirs did when I test them with mine just left your nasty taste my mouth so I don’t do that that often anymore I haven’t done it since then but I’m sure my wife’s been on there sneaking around she does a good job she’s come up with some really good stuff for amazing prices and up until the last event it all tests you real even the gold. So let’s see a picture of your favorite

Cheese and rice 67 carrots and it’s beautiful I think that makes you the forms tanzanite professional so if it hasn’t been heated it’s tricloic and displays three different shades at three different areas or faces and then when you heat it it goes to you presenting two colors correct I believe that’s what I read I haven’t had much experience with tanzanite I think it’s really beautiful I’ve just recently seen pictures of other colors then the normal heated very beautiful blues so when you’re looking at it are the colors different enough to be as drastic as Andralusite. What is it present just three different shades where am I completely wrong and she’s one color like I said I’m not as well diverse intense night as I probably should be. I actually don’t even know the crystal structure is your specimen a natural crystal shape and are you going to keep it as a specimen or what are your plans for it?


Thanks but I’m no where near being a professional (am working on the Gemology Course though)…

Just an ordinary rockhound/metalsmith that had a short stroke of luck, winning an auction. I set a low number (because my wallet would have melted otherwise) and I was sure others would have raised the bid x10 over. When that didn’t happen and the stone was in my hand… I was in complete disbelief. My wallet was a tad bit lighter, though…

Admittedly, the 67 carat value I posted, is probably not an appropriate unit to use, since the stone is rough. There is a significant amount of material that would not produce a cut gem. So the realized weight would be much smaller for produced cut gems.

I have no intention of cutting this one… it’s my precious… :grin:

As for the trichroic behavior, you are correct, most unheated natural should show the blue, purple, and red in the three optical axis. This crystal barely shows the red and I believe that is because along the c-axis, the crystal terminates at an edge, so it is very weak. (The tip is almost razor sharp)

I have two other crystals that do show the red in the c-axis. They do not completely terminate, so there’s an exterior surface available to view into that plane.

Hi Matthew,

Thanks, it was definitely an unexpected treasure find. I made a pact with myself. When a customer requests a stone material that I haven’t used before, I put it on my list to collect a specimen for two reasons…

One: So I can remember that I have actually done something with the material… (helps having a physical reminder)

Two: It provides a backdrop for the commissioned piece when I provide the authenticity certificate to the customer. Plus I can use it for future jewelry designs when I make them using the material.

Adds a signature touch to my artwork… (or the attempt at art… :grin: )


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Ok I would not have mentioned this but it now I feel like it’s relavint so I have.never purchased a gem on eBay because I’ve heard about all the scams that have happened and I know that some still do. With that info I don’t know how some sellers are maintaining an 98% 5 star rating with 5000+ sales.so 3 weeks I decided to check it out for my self by trying to win a auction for Alexandrite I didn’t want to spend a lot just t receive a paste gem (fAke) I lost 5 times being out bid 6th time was a charm so my question is who has won or purchased gemstones from eBay and received what they ordered tested it and it was exactly what they expected has anybody been ripped off using eBay and how would they ripped off what did you receive what did you order( has anybody ever sent one to gia what do you come back at) my pizza alexandrite should be here on the 5th of April so I post a picture in case you wouldn’t really I can’t be a piece of Alexandrite for $40 or maybe you can I’ll find out who’s from the seller with good ratings and a lot of sales

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Looking forward to seeing your purchase!

I have purchased stones, both faceted and rough, from eBay, etsy and others. It is definitely a gamble and honestly, some purchases have ended up becoming decorations in an aquarium… :slight_smile:

I mostly purchase rough cabbing material anymore. I have only bought a few facet rough parcels in the past few years, but haven’t had them tested… they are now going to be my guinea-pigs for practicing what I learn here.

Discovered a long time ago that the feedback ratings are not trustworthy, even if you really dig down into the pile of a seller’s reviews, reading as many as possible. Its very time consuming! I will always contact the seller with questions about the stone. If they respond, that could be a good sign… but how they respond is even better. Their response can tell me a lot about how much I am bothering them for details… if they don’t want to talk…I look elsewhere.

But even that method is not fool-proof… since my fish has all the bling it has never wanted or needed… :smirk:

Ok I’ve made everyone wait long enough these picks are taken in different light sources two picks per light source one with the face of the gem facing the right the color in the cute is the actual best interpretation of the color the next ones are back lit the light is shined in from the back just off center lighting the face through the side of the cullet the cut and polish are amazing but if you look at the proportion of the crown it is very low I believe this is down on purpose so that the right is not coming back up and being more saturated tendency to look black or just way too dark but what was amazing is no right returned to the crown that’s why I was showing the right in these two different ways but for some reason for shining incandescent light straight down the table it returned in my main facets beautiful kind of confuses me because I facet and if you’re passing the right through and why would one light switch come back the I have read that most color changing garnettes are the reddest and most transparent under incandescent lights and that maybe the reason but the knowledge and cutting to be able to get such impressive return under a incandescent light :heart_eyes::fire: to the cutter of my new baby respect and thanks pic#1 incandescent through the crown #2 3 incandescent #45 LED hashtag#67 indirect Sun right

Hi I have been purchasing faceting rough on eBay for over ten years. Unfortunately I only buy from one person. He is a retired rough seller and is well known in the trade. His name is Carl Barney. His store is called lapidary tonewoods and flyfishing. He is also a very well known luther. He is in his 80s now and trying to get rid of all the stuff he has left from years of collecting selling and building guitars. He lives in Connecticut and is a very good person and talented individual.