tanzanian spinels

[Aoife]

Bright Ice - if it's already on its way to AGL then perhaps, in this case, it's better to just let it go ahead as I'm not sure whether it would be possible to cancel the work (presumably you've already instructed them to do it)? I appreciate that this is a considered purchase for you and so for peace of mind, in this instance, it may be worth it. On the plus side, you've now got more information about lab reports and when it might be worth getting one and so can decide in the future what you want to do.

I had another thread about this exact topic that I started the other day as I was considering whether or not to send for one. I wish others had chimed in at that time.

I feel comfortable that I can reverse the work order as they don't have my money yet!

Bright Ice, if you recall, I did ask you why you wanted to get a report on your spinel. I find that on PS sometimes reports are bandied about as though they confer some kind of glow on a gemstone, and, as LD and Gene have noted, they really don't, unless, like corundum, the species of gemstone is frequently subject to treatments that impact value. You seemed to be looking for peace of mind, which is legitimate, but I do think several posters indicated that a report was probably unnecessary.

Regarding "old" vs. "new" Mahenge material, I honestly do not give a flying fig. It's about the color,color color. If something happened to the Mahenge spinels I currently own, and I had to replace them, the last thing I would be asking about would be whether the replacement stones were old or new mined: I'd be looking for the color, and only the color.

 

[bright ice]

Bright Ice - if it's already on its way to AGL then perhaps, in this case, it's better to just let it go ahead as I'm not sure whether it would be possible to cancel the work (presumably you've already instructed them to do it)? I appreciate that this is a considered purchase for you and so for peace of mind, in this instance, it may be worth it. On the plus side, you've now got more information about lab reports and when it might be worth getting one and so can decide in the future what you want to do.

I had another thread about this exact topic that I started the other day as I was considering whether or not to send for one. I wish others had chimed in at that time.

I feel comfortable that I can reverse the work order as they don't have my money yet!

Bright Ice, if you recall, I did ask you why you wanted to get a report on your spinel. I find that on PS sometimes reports are bandied about as though they confer some kind of glow on a gemstone, and, as LD and Gene have noted, they really don't, unless, like corundum, the species of gemstone is frequently subject to treatments that impact value. You seemed to be looking for peace of mind, which is legitimate, but I do think several posters indicated that a report was probably unnecessary.

Yes, you are correct Aoife. What I should have said was that I had hoped there had more people swaying me against a lab report. Hind sight is always 20/20 as they say. I trust those of you who have been in CS much longer than myself.

I am going to cancel the work order Tuesday and have the gem sent back to Victor for completion of my ring. I hate that I even had him send it for me. I was so on the verge of not doing so. But, oh well, lesson learned. I do see the need for corundum.

 

[LD]

Bright Ice - if it's already on its way to AGL then perhaps, in this case, it's better to just let it go ahead as I'm not sure whether it would be possible to cancel the work (presumably you've already instructed them to do it)? I appreciate that this is a considered purchase for you and so for peace of mind, in this instance, it may be worth it. On the plus side, you've now got more information about lab reports and when it might be worth getting one and so can decide in the future what you want to do.

I had another thread about this exact topic that I started the other day as I was considering whether or not to send for one. I wish others had chimed in at that time.

I feel comfortable that I can reverse the work order as they don't have my money yet!

Bright Ice, if you recall, I did ask you why you wanted to get a report on your spinel. I find that on PS sometimes reports are bandied about as though they confer some kind of glow on a gemstone, and, as LD and Gene have noted, they really don't, unless, like corundum, the species of gemstone is frequently subject to treatments that impact value. You seemed to be looking for peace of mind, which is legitimate, but I do think several posters indicated that a report was probably unnecessary.

Regarding "old" vs. "new" Mahenge material, I honestly do not give a flying fig. It's about the color,color color. If something happened to the Mahenge spinels I currently own, and I had to replace them, the last thing I would be asking about would be whether the replacement stones were old or new mined: I'd be looking for the color, and only the color.

Ditto + 1000!

 

[Swala Gem Traders]

Crasru, I never thought you were referring to any of my stones nor to our website. I just thought your post was an interesting one to which I had something to add

ooo~Shiney!, thanks. Beautiful ring !

Gene is right. So far, there is no such thing as new and old Mahenge spinels. Production, for various reasons, has been very poor for the past year or so. However, some top Mahenges have been mined recently. At some point perhaps there won't be any top Mahenge spinels "left" but we're not there yet... Far from it.
Prices have gone up quite a bit as the market has recognized how beautiful the Mahenge spinels were. Demand has gone up. And you now know about recent production...

I'm not quite sure how the insurance companies work and Gene's questions seem to be spot on. I think the only valuable document you'll need if ever something happens to an insured gem is an invoice. But perhaps I'm wrong.

NKOTB: no, you can not tell when a Mahenge spinel was mined. Read above comment.
However, when I see a spinel somewhere (in a shop, in a booth etc) and say "it's a Mahenge", I'm almost always right. They usually have distinct features.

 

[Pandora II]

I happened to be talking to a representative at a UK insurer that specialised in jewellery and I posed the 'I buy a $10k ruby and insure it with you for $10k, it goes missing/stolen... do you give me $10k to buy a new ruby or do you say here's a nice chunk of corundum that cost us $200' conundrum to them.

They are going away to check for sure, but they think that it would be based on information on the receipt. So if you buy your $10k ruby and can produce a receipt for $10k then they will honour that. The problem arises when you buy a $10k ruby for $100 on eBay and they are supposed to believe an apprasial document. So, it appears that bill of sale may trump lab reports and appraisals...

I will report back when I have had the email from this guy - who has gone off to talk to the powers that be.

 

[bright ice]

I happened to be talking to a representative at a UK insurer that specialised in jewellery and I posed the 'I buy a $10k ruby and insure it with you for $10k, it goes missing/stolen... do you give me $10k to buy a new ruby or do you say here's a nice chunk of corundum that cost us $200' conundrum to them.

They are going away to check for sure, but they think that it would be based on information on the receipt. So if you buy your $10k ruby and can produce a receipt for $10k then they will honour that. The problem arises when you buy a $10k ruby for $100 on eBay and they are supposed to believe an apprasial document. So, it appears that bill of sale may trump lab reports and appraisals...

I will report back when I have had the email from this guy - who has gone off to talk to the powers that be.

Thanks Pandora. This sounds logical and acceptable. Hope it is the case.

 

[Aoife]

Yes, you are correct Aoife. What I should have said was that I had hoped there had more people swaying me against a lab report. Hind sight is always 20/20 as they say. I trust those of you who have been in CS much longer than myself.

I am going to cancel the work order Tuesday and have the gem sent back to Victor for completion of my ring. I hate that I even had him send it for me. I was so on the verge of not doing so. But, oh well, lesson learned. I do see the need for corundum.

I empathize with this, Bright Ice, but my personal perspective is that while I am willing to give an opinion, or a what-would-I-do, I really don't want to be responsible for strongly pushing a dissenting opinion (I'm differentiating between fact and opinion here) because there aren't too many hard and fast rules about this stuff. It seemed that you felt a need to send your spinel for a report, and you're the one who needs to be able to sleep at night! On issues like this, you are more qualified to do "the right thing" than anyone else posting on the forum, because it's your gemstone and your ring. That's my philosophy, anyway.

 

[NKOTB]

I happened to speak with my insurance company last week about what might be needed in the event of a claim. While I only have one more expensive item (under 4K, and I don't insure it individually), my overall collection value is what I had been inquiring about. At first, I was told that all of the receipts I have (almost all of my stuff was bought online, so I have Paypal invoices) would be sufficient, but then the woman checked with someone, and came back and told me that I would need an appraisal, with one report listing all of the individual items and their values. Nothing was ever mentioned about lab reports.

Now, if you were planning to resell the stone, could you not get a lab report done then?

As well as "new" and "old" terminology, there is a fair bit of mention of "top colour". Is this not subjective? I have three Mahenge spinels, two of which are considerably lighter than the other one, but all are beautiful. Perhaps this is just as some like medium-toned stones when medium-dark is the "ideal"...

I do wish I had been around for the "old" Mahenge spinels, though, if for no reason other than the old prices!

 

[Arkteia]

It's about the color,color color. If something happened to the Mahenge spinels I currently own, and I had to replace them, the last thing I would be asking about would be whether the replacement stones were old or new mined: I'd be looking for the color, and only the color.

Than is what I am trying to figure out. What do I have to ask for instead of inquiring about "a Mahenge". It may take me a while. I am reading about Tanzanian spinels trying to understand what I buy, why what I buy commands high prices and if I ever see a Mahenge of the quality that made the name famous.

I hope that their era is not gone... But this is another story.

P.S. Sorry for initial misspelling... I think I coined the name "Morongo" from "Matombo" and "Morogoro". Morongo is in California, and it has a casino.

 

[Harriet]

Mahenge or Morongo. Technically, old material and new material is different. But I have many pieces that have been sold as Mahenge (by different vendors) and they do look like "new material". Certificates (not fast track) offer no info about the exact origin. Where should I send them for proof of origin? Would AGL prestige report tell me the exact origin?

No. It just gives the country of origin, not the mine nor the region.

 

[LD]

Mahenge or Morongo. Technically, old material and new material is different. But I have many pieces that have been sold as Mahenge (by different vendors) and they do look like "new material". Certificates (not fast track) offer no info about the exact origin. Where should I send them for proof of origin? Would AGL prestige report tell me the exact origin?

No. It just gives the country of origin, not the mine nor the region.

IF and it's a big IF, they can determine it!

 

[Harriet]

That goes without saying. Neither technology nor scientists are infallible. That's why any statement about origin is prefaced by a qualifier.

 

[LD]

That goes without saying. Neither technology nor scientists are infallible. That's why any statement about origin is prefaced by a qualifier.

Absolutely!

 

[Barrett]

This may not apply to Mahenge material but their is a definite difference between old mine and new mine material in many locations. The variables involved in the formation of gem minerals can vary from one meter to the next during formation. Chemical make-up, pressure, temperature, etc. can all vary greatly in the matter of minutes or meters during mineral formation. Whether it's a primary deposit or a secondary alluvial, colluvial, or elluvial deposit the quality can vary greatly during extraction and mining. Take for instance the Batalha mine in Paraiba Brazil. No copper bearing[as a chromophore] tourmaline was found that was of any significant note until the heitorita trend was struck at 35 meters. Thats when the finest and best quality cuprian tourmaline was found. Anything above and below was secondary to the material found there. So if you dug stright down and hit some so-so cuprian tourmaline then you hit the heitorita trend you would say..." all the old mine material was crap or sub-par to this new mine material". So everything above 35 meters was "old mine" crap and everything at 35 meters and below was "new mine" fantastic.[what do you say once you get back into crappy material ..LOL]

This is especially true with alluvial deposits and I have seen it a number of times while excavating alluvial aquamarine here in GA as well as digging primary veins of amethyst deposits out east. I know nothing of the Mahenge deposits but as they[the miners] dig deeper the morphology of the deposit will certainly change for the better or the worse.

Speaking of Mahenge does anyone know where the neon pinks come from?? Epangko, Baraganga, or Luande mines?

 

[Barrett]

Take for instance this spinel mine in mahenge. As the miners get deeper in the alluvial deposit the morphology changes according to the layout and makeup of the primary deposit they washed down from. Of course you will get a ton of variables that can screw up the overall idea of it but in general and considering all variables equal you could find that older mine material which was near the surface of the alluvial deposit was richer in Chromium when it formed in the primary deposit. As the miners dig deeper they find material which was poorer in chromium when it formed during it's initial primary phase or vice versa. This is just an example and may not and probably does not apply to mahenge material but it's easily understood and readily happens. Hence the term "old mine" and "new mine" to derlineate good or better stones and worse or poorer stones.
The Epangko mine below could have better material in the first 15 meters than it does in the material they are digging today...more chromium in the older st8uff than the newer stuff and all dependent on the formation and chemical makeup of the original primary deposit

 

[chrono]

In general, usually gemstones mined in the earlier stages are of better colour and overall quality than what comes out later. This is probably where the terms "new" and "old" come from. Of course, even stones that are mined from the same mine on the same day can vary greatly in quality but I am talking in generality here. When a consumer is aiming to purchase though, the terms "new" and "old" do not really matter because colour quality is far more important. I've read of some vendors claiming they sat on this particular parcel for years or had it stashed away and etc. but all that is of lesser importance than the actual colour of that parcel of gemstones. I've seen stones where the vendor claims is of "old" mine, yet the colour looks poor or "ordinary" for the type.

Lab reports - again, it depends on the type of stone and the purpose of the owner. I self insure so I do not often need to have a lab memo although I do have some for a select few stones. However, if I do insure under my homeowner's, I will NOT do so without a full AGL write up and will insure only for like replacement or cash out. The way most insurance companies work, even what an appraiser provides isn't necessarily sufficient for the owner to be satisfied with the final payout. Under most insurance plans, the replacement is often of poorer quality because they only go by gemstone type, shape, carat weight, clarity, colour and that's pretty much it. The more details the customer provides, the closer the replacement stone will be. If going for the cash option, be sure you have all the documentation needed and that it is reviewed often enough for inflation or whatever else. I have heard that you need to get your ducks in a row because the receipt isn't always enough. The insurance company might feel that the customer overpaid for the stone (based on the very limited information provided) and thus pay out only a fraction of the original price.

 

[Arkteia]

I need to make some calls and find out more. The more I read, the more I realize how little I know.

I pulled out all my Mahenges, photographed them, then turned upside down and photographed again. What is interesting, that upside down, unpolished, it is all similar material. The difference is in the saturation, and of course, poor cut, with windows, can make even a saturated stone look ugly, likewise, you can hide some ugliness with a nice cut (I have such a stone). Some stones are not included and look very bright, some are included and while pretty, look sleepy, which (to me) takes away from the beauty of the stones. My eyes hurt from looking at photos in my camera. One of them, I hope I shall be able to pull it out sooner or later, looks especially telling. Three stones side by side, and you can see what a difference good saturation makes. "Hot pink" material, in fact, is of the same origin as dull-brown.

The only thing I can not fathom is where the brown comes from. Is it iron or manganese?

And BTW, you can find desaturated material at a very high price. I just watched a video...

 

[Pandora II]

I need to make some calls and find out more. The more I read, the more I realize how little I know.I pulled out all my Mahenges, photographed them, then turned upside down and photographed again. What is interesting, that upside down, unpolished, it is all similar material. The difference is in the saturation, and of course, poor cut, with windows, can make even a saturated stone look ugly, likewise, you can hide some ugliness with a nice cut (I have such a stone). Some stones are not included and look very bright, some are included and while pretty, look sleepy, which (to me) takes away from the beauty of the stones. My eyes hurt from looking at photos in my camera. One of them, I hope I shall be able to pull it out sooner or later, looks especially telling. Three stones side by side, and you can see what a difference good saturation makes. "Hot pink" material, in fact, is of the same origin as dull-brown.

The only thing I can not fathom is where the brown comes from. Is it iron or manganese?

And BTW, you can find desaturated material at a very high price. I just watched a video...

LOL, I remember looking at the FGA course theory notes - two thick files that weighed over 10lbs each - and thinking wow, when I've learnt all this I will know a heck of a lot. Now I know them all, I've realised that while I have learnt a lot, I have merely touched the tip of the iceberg of many different things!

Regarding chromophores - Mahenge spinels are coloured by chromium which also gives them their fluorescent nature. There may also be manganese in the make-up - manganese generally gives a pink colouration. Iron is the destroyer of fluorescence and also lends a brownish tinge to a lot of red/pink stones - it's what makes Thai and Cambodian rubies less glowy and browner than their Burmese, Sri Lankan and Vietnamese counterparts.

Ruby and spinel are very similar beasts - ruby is aluminium oxide and spinel is magnesium alumium oxide and they are often found growing together (Mogok for example) as the ruby starts to form from the leftovers once the supply of magnesium has run out! Hence they often share the same chromophores.

 

[bright ice]

I need to make some calls and find out more. The more I read, the more I realize how little I know.

I pulled out all my Mahenges, photographed them, then turned upside down and photographed again. What is interesting, that upside down, unpolished, it is all similar material. The difference is in the saturation, and of course, poor cut, with windows, can make even a saturated stone look ugly, likewise, you can hide some ugliness with a nice cut (I have such a stone). Some stones are not included and look very bright, some are included and while pretty, look sleepy, which (to me) takes away from the beauty of the stones. My eyes hurt from looking at photos in my camera. One of them, I hope I shall be able to pull it out sooner or later, looks especially telling. Three stones side by side, and you can see what a difference good saturation makes. "Hot pink" material, in fact, is of the same origin as dull-brown.

The only thing I can not fathom is where the brown comes from. Is it iron or manganese?

And BTW, you can find desaturated material at a very high price. I just watched a video...

Is this a video that can be viewed somewhere?

 

[Arkteia]

If you go to a well-known website that sells expensive Mahenges, with videos, and watch one very carefully, you'll see a stone that in my mind is lacking in saturation. Or at least is not saturated enough to justify the price. JMO

 

[Barrett]

Great post chrono!