Size matching Demantoid gemstone to diamond sides

[perry]

I''m on the 20th or so revision of an engagment ring.... (as if I''m actually counting).

Green center stone, and using the "side" diamonds I have.

Not interested in synthetic emerald, glass, or other things. If I''m going to do it - I want something that looks great and is easily identifiable as natural (and rare) by someone who knows gems. It also has to be reasonably durable...

Thus, Demantoid - Russian Demantoid pops up. Interesting stone - you can read about them here:

www.gemstone.org/gem-by-gem/english/demantoid.html

www.pgrgem.com/color/datasheets/pgrdgar.html

And saving the best for last (and my understanding: the main - if not the only source - for Russian Demantoid):

www.palagems.com/demantoid_garnet.htm


I have two problems to resolve: The actual selection of which one (It''s not like jewelers have a selection to chose between - most jewelrs have not even heard that it is again available (in limited quantities -even if the have ever heard of it). I''m working on that (withoug flying to the west coast).

But more imporatant: Non-Diamond gemstone sizeing is different than diamonds. Often they are cut deeper in order to maximize their color and brillance.

So you cannot go by weight of the stone like you can with superideal cut diamonds when matching a center stone to side stones.

I have two 1/4 carat diamonds @ 4 mm diameter (from GOG). I want the Demantoid centerstone to stand out - and be accented by these diamonds.

Thus, do I need a centerstone that is 6 mm or larger diameter if chosing a round (note in the diamond world a round 3/4 carat daimond would be 5.9 mm - which is what I considered the smallest diamond to properly ballance 1/4 carat sides).

What about an oval or cushion cut: would I need to have the minor dimension (the thin side of the oval) be at or more than the diameter of the round diamonds.

Or - would I need to have a larger Demantoid Centerstone in order to prevent the dazzling diamonds from overshadowing it?

Let me know.

Perry

ps: for those wondering: yes, after all the frustration last year - "D" and I are again talking - and have discussed what happened and why: The "Slug" is gone.

 

[valeria101]

Hm... don't think color and diamonds would 'compete' - they make a great match whichever way it turns(white center or sides, whichever shape). Between diamonds and dems, I'd rather give center stage to the green stone, sure that! Besides any abstract order of priorities, diamonds do better in small stones than demantoid garnets - tiny demantoids have greater chance to look not quite so bright and probably less nicely colored to boot, while tiny diamonds still deliver bright pinfire. There should be some smart explanation for this I am afraid to speculate about right now - this is just a personal impression; if you have a chance to see for yourself, you might well disagree... who knows.

Re weight: 6mm may be a bit above 1 carat (1.3-ish perhaps) and I would not shy away from deeper cut round stones as long as they are brilliant. A fancy shape may take more, depending on what it is. Spready ones are not too common, as far as I know. Did anything catch your attention online just yet?

As far as I know....

Now, speaking of greens, 'thought you might like to see how a few great green stones match up

Link to source

Easy to guess which your favorite is! IMO, the two garnets there stand out like a brilliant thumb

Just make sure the ring has a sensible setting and it never gets near any jewelry cleaning device other than a small soft brush & soap.

Btw. to the nice list of references about demantoid, I would add one for the record - about how and where dems come out of the ground and where they rank among garnets: demantoid gallery at Mindat

 

[perry]

Thanks Val:

It would be a green center stone. As far as which one.... "D" gets to pick as soon as I can arrange to have a selection here when she is here.

If you go to the Palagem site (my last reference), and find the search feature on the upper left for gemstones - and do a search for Garnet - Demantoid - I don''t think you will be disapointed in the selection (or for may other gems as well). My understanding is this is all (or almost all) Russian Demantoid - which can be easily seen by loupe inspection of the stones (and adds price as well).

My understanding is that these folks tend to stay on the better cut - higher class - stones available (we all know that there are a lot of junk stones out there). Wink Jones sent me to their site (one of his sources).

Hope you enjoy the search.

Perry

 

[Gemklctr]

Perry, you might want to check the stone below out a AJS Gems (for some reason the photo does not post). Demantoid is one of my personal favorite stones and would make a unique and very special engagement ring. I think the proportions of the stone below would work well with 1/4 ct diamonds. I have only seen one round demantoid over one carat in almost 20 years of gem shows. Good luck.

http://www.ajsgems.com/GDT/GDT-00018.htm
Demantoid Garnet - 1.29 cts. Cushion

Natural Demantoid Garnets - Loose Urals Mount, Russia Demantoid Garnet
previous page Demantoid Garnet Index


Weight:1 pc. - 1.29 cts. Size: 7.7 x 5.1 x 4.3 mm
Shape: Cushion Cut: Diamond Cut
Clarity: Loupe Clean Enhancement: Unheated
Type: Demantoid Garnet Origin: Urals Mount, Russia
Lot #: GDT-00018 Stone Price: $2,700.

 

[perry]

Thanks for the link GK:

However, Wink Jones is my preferred jeweler for this purchase as he has been working with me on this (unless he were to recommend another who just happened to be local to me). We just need to manage the logistics of having some relevant samples in my hand the next time "D" comes to visit so she can pick what she wants.

Perry

 

[colormyworld]

Just curious ia there any reason why it will be a demantoid.

 

[Amandas_Jewels]

What a nice choice!

 

[perry]

Colormywold asked:

Just curious ia there any reason why it will be a demantoid.


Several. First, "D" does not want to spend the $ for a larger diamond centerstone and wants a emerald green stone . Quite honestly - she would be happy with a $10 piece of colored glass. Add to that is the fact that high quality natural emerald is on par or more expensive than diamond (so is high quality natural Ruby: In the order of things - pricewise I think it goes for top of the line stones: Ruby (most expensive), Emerald, Diamond, Russian Demantoid (or at least I am not aware of any other semiprecious stones that can cost as much as Russian Demantoid).

Of course, there are several emerald synthetics out there - which would work for "D". But....

I want something that is easily identifiable as a natural stone; something that when people ask - "is that real" both of us can say yes (even if they don't understand what the gem is).

As an added bonus: Demantoid has great "fire" in comparison to many other gems. Admitedly not as spectacular for the deeper greens - but still I am told that they stand out compared to other semi-precious gems.

How can a person tell if the emerald they are wearing is real? (D and I looked at some "natural" emerald E-Rings rings - judging from the price I think that are lab naturals - but the sales person - who hasn't worked there long enough to get business cards and admitted that she did not know that much about jems - was sure that they were "real" and not lab grown). How do you tell? Yes some of the lab ones have been doped to florese under long wave UV - but it also seems that that some of them have not (I am quite sure that everyone carries a long wave UV light with them when shopping for gems... just to check on the sales person's claims....

). They have even come up with a synthesis process that creates the correct kind of inclusions that are eyevisiable in natural (and hydrothermal process) emerald.

There will never be a question with Russian "horsetail" Demantoid. No one can synthesize the horsetails.... (even though garnet can be sythesized).

Now I was not buying top of the line diamond (D IF) - and won't be buying a top of the line Demantoid: I save money (a concern of D's) and have a great green stone that is easily identifiable as natural.

Not that I have no problems with synthetic gems (or even colored glass) for lesser jewelry. But the engagment ring is special... I want it to be real.

Perry

 

[MJO]

Date: 4/17/2006 7:53:04 AM
Author: perry
Colormywold asked:

Just curious ia there any reason why it will be a demantoid.


Several. First, ''D'' does not want to spend the $ for a larger diamond centerstone and wants a emerald green stone . Quite honestly - she would be happy with a $10 piece of colored glass. Add to that is the fact that high quality natural emerald is on par or more expensive than diamond (so is high quality natural Ruby: In the order of things - pricewise I think it goes for top of the line stones: Ruby (most expensive), Emerald, Diamond, Russian Demantoid (or at least I am not aware of any other semiprecious stones that can cost as much as Russian Demantoid).

Of course, there are several emerald synthetics out there - which would work for ''D''. But....

I want something that is easily identifiable as a natural stone; something that when people ask - ''is that real'' both of us can say yes (even if they don''t understand what the gem is).

As an added bonus: Demantoid has great ''fire'' in comparison to many other gems. Admitedly not as spectacular for the deeper greens - but still I am told that they stand out compared to other semi-precious gems.

How can a person tell if the emerald they are wearing is real? (D and I looked at some ''natural'' emerald E-Rings rings - judging from the price I think that are lab naturals - but the sales person - who hasn''t worked there long enough to get business cards and admitted that she did not know that much about jems - was sure that they were ''real'' and not lab grown). How do you tell? Yes some of the lab ones have been doped to florese under long wave UV - but it also seems that that some of them have not (I am quite sure that everyone carries a long wave UV light with them when shopping for gems... just to check on the sales person''s claims....

). They have even come up with a synthesis process that creates the correct kind of inclusions that are eyevisiable in natural (and hydrothermal process) emerald.

There will never be a question with Russian ''horsetail'' Demantoid. No one can synthesize the horsetails.... (even though garnet can be sythesized).

Now I was not buying top of the line diamond (D IF) - and won''t be buying a top of the line Demantoid: I save money (a concern of D''s) and have a great green stone that is easily identifiable as natural.

Not that I have no problems with synthetic gems (or even colored glass) for lesser jewelry. But the engagment ring is special... I want it to be real.

Perry

Hello Perry,

Demantoids are wonderfully bright stones but are expensive and go up substantailly in price per 1/2ct incremients. Have you considered tsavorites which are a bit harder so are better for everyday use? You can also get a bigger stone for the money.

BTW you said garnets can be sysnthetic? I have not heard this. Where did you see it?

If you are sure you want a demantoid Michael at Gemlineinc just got a round bright 1ct+ chrome green with horsetails seen only under heavy magnification. He has been dealing directly with a Russian Miner. I know Michael is out of town right now visiting an ill father so you might not be able to reach him. I have a picture of the stone he sent me because I am thinking of getting it but the picure is too large to upload here. I will see what I can do to make it smaller. I''m not very good at this.

Happy End of Tax Season,
Maurice

 

[movie zombie]

glad you survived Tax Season, MJO! and glad to know you''ll have more time to participate here re color stones.

i, too, have never heard that garnet can be synthetic....but anything is possible, i guess. the other plus about garnet is the lack of treatment.

movie zombie

 

[Richard M.]

Date: 4/17/2006 10:49:05 AM
BTW you said garnets can be sysnthetic? I have not heard this. Where did you see it?

At present there are no commercially available synthetic garnets. There are man-made stones called "garnets" but they are not synthetic garnets. A synthetic must be chemically and physically identical to its natural counterpart.

Yttrium Aluminum Garnet (YAG) and Gallium Gadolinium Garnet (GGG), for instance, are called "garnets" because they have cubic crystallization. But natural garnets are silicates and GGG, YAG and some of the newer entires like YIG (Yttrium Iron Garnet) are not. Their chemistry and properties like R.I., S.G., spectra, etc. are entirely different than natural garnets.

That said, I have a pair of green YAGs given to me by Judith Osmer, former producer of Ramaura Ruby, that''s very hard to distinguish from natural demantoid by eye. I have them carefully marked so I don''t accidentally mistake them for a nearly identical natural pair I own.

Richard M.

 

[MJO]

Date: 4/17/2006 1:42:28 PM
Author: Richard M.

Date: 4/17/2006 10:49:05 AM
BTW you said garnets can be sysnthetic? I have not heard this. Where did you see it?

At present there are no commercially available synthetic garnets. There are man-made stones called ''garnets'' but they are not synthetic garnets. A synthetic must be chemically and physically identical to its natural counterpart.

Yttrium Aluminum Garnet (YAG) and Gallium Gadolinium Garnet (GGG), for instance, are called ''garnets'' because they have cubic crystallization. But natural garnets are silicates and GGG, YAG and some of the newer entires like YIG (Yttrium Iron Garnet) are not. Their chemistry and properties like R.I., S.G., spectra, etc. are entirely different than natural garnets.

That said, I have a pair of green YAGs given to me by Judith Osmer, former producer of Ramaura Ruby, that''s very hard to distinguish from natural demantoid by eye. I have them carefully marked so I don''t accidentally mistake them for a nearly identical natural pair I own.

Richard M.

Hello Richard,

Thanks that is what I thought. Below is a picture of the new stone Gemlineinc got in.

 

[pricescope]

Date: 4/17/2006 7:53:04 AM
Author: perry


There will never be a question with Russian 'horsetail' Demantoid. No one can synthesize the horsetails.... (even though garnet can be sythesized).

Perry

Coincidentally just 3 day ago we were having dinner with our college friend in NYC who is in research field of semiconductors growing for the last 25 years (he deserves Guiness for that)
.
Funny enough, horsetail in demantoids was my last card to play, and he said "Honey you forgot everything they taught us...

" (and i did).
He said "Russians now can grow Degas's Races in garnet if you pay enough for the research".

Hee hee, it would be still Russian tails though.

Said that, please lets stay within natural stones in PS threads.

 

[colormyworld]

Perry the reason I asked was demantoid is a little less hard than tsavorite as MJO pointed out. A tsav. will not have a play of color like a demantoid but a darker green demantoig will not show as much color as you have said. I think if you can another choice might be a very good alexandrite. I have seen some that look similar to emerald in day light with the added bonus of looking purple red in indoor lighting. Alexandrite is right below sapphire in hardness also. that woul be very unique. Lots of luck with what ever you choose and congrats.

 

[Richard M.]

Date: 4/17/2006 4:39:23 PM
Author: colormyworld
Perry the reason I asked was demantoid is a little less hard than tsavorite as MJO pointed out. A tsav. will not have a play of color like a demantoid but a darker green demantoig will not show as much color as you have said.

Demantoid is the softest of the garnets (about 6.5 Mohs) and I don''t consider it a good choice for a ringstone unless it''s in a protective setting. Tsavorite (green grossular) runs 7 - 7.5 and would be a better choice IMO. Dark green demantoids don''t show much dispersion ''fire'' anyway: the deep color masks it, as colormyworld says.

Demantoid ''fire'' is at its best in the lighter green to yellowish-green colors. Tsavorite greens aren''t quite the same as demantoid greens though. Demantoid is colored by chromium, green grossular usually by vanadium. They''re both pretty but different.

Richard M.

 

[perry]

Concerning synthetic garnets: The information I saw only mentioned that "real chemical match" synthitic garnets had only been done in a lab - and their was no commercial production of the product. I''m not even sure if they had done it for gemstone purposes (the most common reasons for growing various crystals is industrial - not gemstones). Whatever - it did not work for whatever they did it for - or it wasn''t considered cost effective. Just that someone knows how to do it if they want to.

I had seen similar information as what Richard M mentioned above about the other "non-chemical match" so called garnets in production.

Perry

 

[valeria101]

Date: 4/17/2006 4:39:23 PM
Author: colormyworld

Alexandrite is right below sapphire in hardness also. that would be very unique.

Hei, that''s precisely what I was thinking! (natural stone, a distinct look, at least some of the time green

). Not much less expensive than diamonds though.



Adding a vote for tsavorite garnet being more wearable to what everyone says. ''Gues demantoid would not be disaster, but this one is well into carefree territory, IMO.

 

[FireGoddess]

Perry I don''t know much on the demantoid front but I do want to say that I''m glad things worked out for you and D, that the slug is gone, and that you both have taken the time to work through things....I hope she loves and treats you as much as you deserve, which is a LOT.

 

[icekid]

Perry- I''m so glad to hear things are working out for you and D.

And I totally can''t wait to see what you come up with for the ring. I love all things green, and I think tsav, demantoids...

any gorgeous colored stone will make a stunning ring w/ the side stones that you picked out!

 

[WinkHPD]

Date: 4/16/2006 10:17:40 PM
Author: perry
Thanks for the link GK:

However, Wink Jones is my preferred jeweler for this purchase as he has been working with me on this (unless he were to recommend another who just happened to be local to me). We just need to manage the logistics of having some relevant samples in my hand the next time ''D'' comes to visit so she can pick what she wants.

Perry

Thank you for your vote of confidence and support, it is very welcome and greatly appreciated.

In the example of the demantoid that Maurice posts above you can see orange, yellow, blue and green dispersion. Yes, it is more subtle because of the strong green color of the demantoid, but it is visible. You have been correctly advised that your wife will have to be careful with this gem, but she would also have to be careful with emerald, tsavorite or even the green glass that you mention that she would be happy with. With normal care it should wear for many years, and so long as there is no major damage, she should be able to have it repolished in when it becomes necessary with only minimal weight loss.

Wink

 

[Richard M.]

Date: 4/17/2006 6:15:59 PM
Author: Wink
In the example of the demantoid that Maurice posts above you can see orange, yellow, blue and green dispersion. Yes, it is more subtle because of the strong green color of the demantoid, but it is visible.

That particular stone is a lighter-toned yellowish-green. Deep chrome green demantoids often display no dispersion even in direct sunlight. But their color is wonderful -- it''s a trade-off. As for demantoid durability as a ringstone in an unprotected setting, opinions and experiences vary. I''m the conservative sort.

Richard M.

 

[perry]

I am aware of the potential durability issues with garnet, emerald, and other non-diamond gemstones. Guess that''s one reason they make custom rings.... More protection than normal can be built in. Also, Demantoids (and other gemstones) tend to be deeper than diamonds so just using a setting designed for a diamond may not be appropriate.


Anyway, thanks for all the advice.

In the end I''ll probably work with Wink on a setting as well.


Also for those who have noted my progression with "D" - thanks...

Perry

 

[WinkHPD]

Date: 4/17/2006 6:45:39 PM
Author: Richard M.

That particular stone is a lighter-toned yellowish-green. Deep chrome green demantoids often display no dispersion even in direct sunlight. But their color is wonderful -- it''s a trade-off.

Richard M.

That is certainly true, the color of a nice demantoid is spectacular. If they are well cut, even the dark green can display dispersion. But some of them are so beautiful that I would take them with or without the dispersion, just for the color.

Wink

By the way, one of the most dispersive stones I have ever seen was a daaarrrrrrkkkkk green almost black chrome tourmaline, but worn in the sun it became a blazing ball of reds, yellows, and greens in a deep dark green back ground. I sold it to a lady who only wears it to garden parties in the spring and summer, as it is lifeless in any other lighting.

 

[Hest88]

I know you really can''t see any real colors in this picture (and my bad photography skills), but these are my three demantoids that are on the darker side of green. Under sunlight, they actually have quite a nice play of red and green flashes. My larger one, which is an even more olive green, also has the same effect. The dispersion is definitely not as obvious as with lighter stones, but still lovely and the stones themselves are noticably "bright" when side by side with other colored stones.

 

[pricescope]

How''s your project going Hest?