how to id demantoid?

[partgypsy]

You guys (in colored stone forum) are so bad. I was trying to refrain from gem buying, but ended up on ebay bidding on a bunch of gemstones and in 2 different auctions winning two "demantoid garnet". The first I received and am pretty sure it is demantoid. The second one I just won, will take a couple weeks to arrive. But I have some concerns. It is advertised as new find - Madagascar demantoid. I know sphenes which also can have the green color and the great dispersion are found there, but only know of the Russian and Namibian demantoids. I even asked the seller how it was id''d and how know it''s not a sphene, seller replied that not a sphene, hardness is different and would refund my money if not a demantoid.

So it will probably take me a couple weeks to get it, but once it gets here I would love any comments of what to do to determine whether I bought an expensive sphene or an inexpensive demantoid!

 

[Barrett]

There actually was just a brand new find of demantoids in madagascar..brand spanking new. I would be a little wary for the simple fact that the seller must have a direct connection to madagascar and a dealer there to have acquired some cut stones already but on the other hand if the seller''s feedback is good and you know he is trustworthy(you dealt with him before or you just know) then it''s very plausible that your stone is the real deal. Those stones have not hit the market in full force yet so you have one of the first(you know what I mean..not one of the first literally) batches of cut demantoids from there. As with most new finds and stones found in madagascar there is now like 20,000 people there trying to find more. I would be willing to bet you do have a brand new demantoid from there and the first PS''er to have one from that location. I know that large singles and crystal clusters have been found there with some reaching up to 2cm. They have excellent tranparency too. Very cool. Check with your loupe and see if it has any sembelance to russian with horsetail..probably not but still would be cool to check. Check the feedback carefully(if less than 100% read through until you find and negs and read those) if all looks good then..I am jealous as I love demantoids and I would love to own one from the new madagascar find.

 

[partgypsy]

It is a large volume power seller whom I have not purchased before; seller would have 100% but 6 recent negative feedback was from 1 person who said had not received 6 stones yet (reply was buyer in australia sometimes takes longer). But of those who received stones people seemed happy.
The stone is a light bright green color, 6.1 mm round. Does have some inclusions along the edges of the stone but otherwise pretty clear. When I''m at home I can attach a picture I took from the auction. Either way it won''t break the bank, won it for 137.

 

[Barrett]

awesome...I would love to see a pic..it will more than likely be the first cut madagascar dem that anybody on PS has seen..very cool...I heard they were very sharp to so it should twinkle like nobody's business..the only reason that I was or am a little skeptical is us mineral specimen junkies have not seen a min. spec. from there even though word is some awesome matrix specs. have been found..usually if some goods specs(for mineral dealers) have been found than they are whisked out of there and to the big timers here across the US..might have to go search and see if I can find any specs. for sale..maybe I am a little behind on the times ..so take what I said at face value until otherwise...

 

[partgypsy]

Thanks amethystguy for your info, very interesting there are demantoids coming from Madagascar, but sounds unclear whether it is in the market yet. The same seller has at least 1 other stone titled that way so you can do a search. Well I know I am taking a risk (doing stuff I advise other people not to do!) but it will be fun to see what it looks like in person.

 

[Barrett]

It''s just cool to know that you will be the first on your block to have one. I love those little green diamonds

 

[Richard M.]

Date: 6/25/2009 2:43:57 PM
Author: amethystguy
It''s just cool to know that you will be the first on your block to have one. I love those little green diamonds

A.G.: Has Madagascar''s ban on gem exports been lifted? Last I heard their President had made it illegal to export any gems until a problem over a large emerald sent to France had been settled. Not that smuggling doesn''t happen but the embargo raises a question.

Part Gypsy: There''s no way to absolutely ID the stone without the services of a qualified gemologist. Namibian demantoid can have some striking resemblances to green sphene and both gems are over the R.I. limits of standard refractometers. Garnet is singly refractive and sphene is double so that would be a quick way to separate them. Do you have the knowledge to do that? Even so the "demantoid" could be another type of garnet such as a Mali Grandite. You''re in tricky territory.

 

[Barrett]

I had no idea there was a ban to begin with...I ordered a small parcel fo rough back in febuary from Antananarivo..oops..does that mean I am a smuggler? Do you have access to a dichroscope..you could tell by using one of those.

 

[partgypsy]

Thanks Richard.
I was thinking maybe there was a way to compare dispersion, that sphene''s dispersion is more and can somehow be distinguished from demantoid but doesn''t sound like the case. I am rusty about the single/double. I remember when people were talking about moissanite how sometimes can tell doubly refractive by looking at the facet reflections inside the stone, and also that the "fire" is refracted twice as well, but I could be misremembering. If I went to a jewelry store that specialized in gemstones, would they be able to tell, or would it require specialized equipment?

 

[Richard M.]

Date: 6/25/2009 3:23:06 PM
Author: amethystguy
I had no idea there was a ban to begin with...I ordered a small parcel fo rough back in febuary from Antananarivo..oops..does that mean I am a smuggler? Do you have access to a dichroscope..you could tell by using one of those.

Did you ever receive the parcel? If so maybe they''ve relaxed the embargo although I doubt their Customs can check every parcel sent out. I can''t find any recent news but several cutters who went there on a buying trip not long ago had their purchases embargoed by the government.

Richard M.

 

[Richard M.]

Date: 6/25/2009 3:35:49 PM
Author: part gypsy
Thanks Richard.

If I went to a jewelry store that specialized in gemstones, would they be able to tell, or would it require specialized equipment?

Frankly, most retail jewelers don''t have the gemological knowledge to deal with that problem. Many might be able to tell single from double refraction but they probably couldn''t distinguish grandite (andradite) from demantoid. Many are just realizing that not all garnets are red. As for the dispersion difference, it can be measured but it''s not a simple job.

 

[partgypsy]

Thanks Richard. I guess my follow-up question would be what would be the least expensive way to send off the stone to get an gemological identification (doesn''t need to be detailed for insurance purposes or anything).

 

[Roger Dery]

Date: 6/25/2009 3:46:01 PM
Author: Richard M.

Date: 6/25/2009 3:23:06 PM
Author: amethystguy
I had no idea there was a ban to begin with...I ordered a small parcel fo rough back in febuary from Antananarivo..oops..does that mean I am a smuggler? Do you have access to a dichroscope..you could tell by using one of those.

Did you ever receive the parcel? If so maybe they''ve relaxed the embargo although I doubt their Customs can check every parcel sent out. I can''t find any recent news but several cutters who went there on a buying trip not long ago had their purchases embargoed by the government.

Richard M.

Hi Rick,
How are you??

When we left Tana last July, the restriction of rough was still in place. I tried to arrange for the balance of my rough to arrive in the US with Tom Cushman just before the Tucson show opened in early February, but he was unable to arrange it. So my goods are currently sitting in a safe. Just last week we sent US$300 (as a good will gesture) to ''assist'' with movement of rough, but I believe it is of no avail.

Since cut goods can readily leave the country, we are now thinking of having the balance of the rough faceted by the local cutters and then I will recut it once here. As they say.... it''s always somethin''.

Hope this answers your, and AmethystGuy''s question on what''s going on with rough from Madagascar.

Am leaving for Arusha in 5 days, not expecting any problems there....

 

[Richard M.]

Hi Roger,

Good to see you here. I guess I missed the distinction between rough and cut goods. I checked a number of sources but couldn''t find much written about the current Malagasy situation.

Wishing you the best of luck on your Tanzanian adventure.

Richard M.

 

[Richard M.]

Correction on my last post. Demantoid is a variety of andradite; grandite is a mixture of grossular and andradite.

I believe GIA does gem ID''s quite reasonably, looks like about $85 for a garnet under 3 ct. That''s all it is: an ID with little other data. You can Google GIA Gem Trade Lab. You might also fire off an email to AGL to see if they do such IDs as part of the Gem Brief program. They''ve recently undergone an ownership change: http://www.aglgemlab.com/

Richard M.

 

[partgypsy]

Here is a cropped pic.

 

[chrono]

I was wondering if you can send it to AGL for their lab brief which only costs $25?

 

[Richard Sherwood]

It does have the "look" of demantoid.

Pretty color, with nice intensity.

 

[chrono]

Generally how long does it take for a new find to hit the market?

 

[icekid]

Looks like a pretty stone- I was thinking the AGL brief might be the most economical, too, if that is an option.

 

[partgypsy]

This is a stupid question, but how do I submit it to AGL?

I think my plan of action is when I get it, see if I like it. If I don''t care to do anything with it, will not pursue (throw it in a drawer : ). If I like it enough to set, will do the very economical AGL id.

 

[partgypsy]

nevermind I see the link

!

 

[Barrett]

I have no idea about cut gems but I am sure it is just as quick as specs. American dealers and European ones have networks of dealers in these countries that pounce at the first sign of something new...I am sure cut stones is pretty quick also..seems like those Thai guys are everywhere

 

[partgypsy]

Sorry for taking so long but I only got the gemstone today! Over the holiday weekend apparently they put the slip of paper into someone else''s mailbox, and this was the first day I could pick it up!

First impression, is that it is more included than my original demantoid. It actually has a "chunk" of brownish something on one edge. Compared to the Namibian which was lime, almost with a little blue this one is more of a khaki type green, but very attractive fire. To my own uneducated eyes it does look similar to the demantoid purchased from trusted dealer. Also in the pics is a another smaller (.89 ct) demantoid I purchased from a different vendor. The smaller is the more preferred and a attractive color but slightly less fire (not sure if due to material, being darker or cutting).

 

[partgypsy]

Here is another picture, where the flash caught one stone but not the other, can see how the stone really likes the light. This also reiterates how crappy I am at taking pictures of gemstones. I try to get closer, but it is all blurry. Need to review some tutorials!

 

[partgypsy]

I am happy with the way it looks and would definitely not mind setting this into a pendant (simple bezel).
But as you may or may not be able to tell, has an inclusion along one edge. It doesn''t bother me that it has a visible inclusion, but concerned as it would be where it would be set, if it affects the integrity of the stone setting-wise and would not be able to set it.

I wonder if I should first see if it is settable, before trying to get that AGL id report?

 

[pitbullmom]

I get a lot of magazines and emails alerts from various colored stone publications/writers etc and have read some very brief info on the
new find in Madagascar of demantoids which had me interested since they are one of my favorite colored stones to collect and design with.
I'm no professional, but have spent a lot of time reading, studying GIA textbooks and learning from others that are considered experts along with a few GIA's as well, and my jewelry design is strictly for myself and my daugthers or friends.

I got email from one of the big gem dealers on Ebay about the new stones listed and among them were the Madagascar Demantoids so
I had to buy one to see what it was all about. Unfortunately I'm not home, on road with husband for our business so my daugther did
open the packages of the first 2 that arrived and described them to me, and louped them but she does not know how to use my
various testing equipment at home, commented when she went to my box of Demantoids that they were very similar to my Namibian's vs.
the Russians, nice color and a lot of flash and sparkle with some hints of red flashes when light hit the stones the right way. She did scan them and email it to me but it did not come out the best, but good enough to have that tell tale flash and glimmer of a demantoid which
is very unique to it, yes they resemble sphene but they do have some physical properties that seem to be unique to them.

I was doing more research online about the Madagascar stones when your site came up and I thought ; heck I check here often for info so why not register. I also came across this recent article.. Its photo # 5 and 6 down of the Madagascar crystal rough.. thought some of you might enjoy seeing this at http://www.crystalclassics.co.uk/news-story.php?id=54.

Once home I'll test mine and if time permits take it over to a local GIA that can test further for me depending on what his immediate
reaction is since they are one of his favorite stones as well.

My daughter said the one that arrived today before she was leaving my office had a color very similar to my Namibian but much more electic and brighter and it was just glistening and sparking in the sunlight and under the office ilghts.. I'm excited to see and test it since they seem to come in larger sizes as well, the last one was about 2.88 carat. The dealer I've bought them from I've dealt with many times over the past years and his stones have always been what were advertised and often better than the photos and descriptions. When it comes to Ebay feedback you really have to read the negatives to be fair. I know a couple of the big colored stone dealers quite well over the years
and most of their feedback that was negative was from scammers or people that had no clue about what to look for and how to collect. One of the dealers was so upset over the first and ONLY negative feedback he's ever received, fedex'd me the stone to prove his point.. it
was exactly as his photo showed and his text described.. I guess the buyer didn't know what I3 meant... even though this dealer like
all the reputable ones have the standard grading scales listed. So often the dealer sellers are being honest but some of the negative feedback clients are clueless.

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[partgypsy]

Thanks pitbull mom for that link beautiful pictures! I originally come from Illinois which is not known for gems but does have alot of fluorite (though those blue and purple ones are great!).

Although the piece I won is definitely not perfect due to the inclusions, you don''t really notice them in person due to the great play with color.

Please post again when you have a chance to look at your new treasures. I''d love to see pics and also the results of your investigation.

 

[T L]

Demantoids are on the soft side for garnets (hardness 6.5), so make sure you use a skilled benchperson to do the job. Most benchpeople are only familiar with diamonds and corundum (sapphires, rubies).

 

[demanspark]

hi everyone...
sorry i was jus reading pitbullmom''s post and was wondering if you guys have recommendations on those "big gem dealers on Ebay"

I was kinda oogling at stuff they have posted.. but never really knew who to buy from..