Emeralds - Can they be coated?

[anne_h]

Hi,

I have just received my first piece of emerald jewelry (the appraisal is tomorrow).

In the mean time, a question... The emerald has some inclusions, which I am fine with. However, the color looks... fake. Like, a very pleasing green and really uniform. Note that the stone was sold to me as natural (not synthetic).

I know of the concept of gemstone coating to enhance color. Have we heard of this being done on emeralds?

Or what else could make the stone look so "good"?

Thanks for any info,

Anne

 

[chrono]

Emeralds are generally oiled and some are filled with resin to lessen the appearance of the inclusions. Sometimes, the oil and resin are coloured, thereby improving the natural colour of the emerald.

 

[anne_h]

Thanks Chrono!

For colored oil or resin filling... would that give the entire stone a uniform color? I always assumed just the filled fractures would have their color altered (?)

To me, this stone''s color is seeming *too* pretty and uniform to be true, for the price I paid. I am also paranoid that the facet junctures seem slightly think (coated??)

Open to any ideas!

Anne

 

[SB621]

Hi Anne,

I''m not an expert but I believe it does. Emeralds can also be heated to help improve the color which will give it that uniform look as well.

 

[serenitydiamonds]

Date: 12/10/2009 2:16:49 PM
Author: Chrono
Emeralds are generally oiled and some are filled with resin to lessen the appearance of the inclusions. Sometimes, the oil and resin are coloured, thereby improving the natural colour of the emerald.

Very rarely are the oils colored or dyes and it would be on very very low quality emeralds. Because of how emerald inclusions are, it would be very obvious and unattractive this way.

--Joshua

 

[serenitydiamonds]

Date: 12/10/2009 11:12:57 AM
Author:anne_h
Hi,


I have just received my first piece of emerald jewelry (the appraisal is tomorrow).


In the mean time, a question... The emerald has some inclusions, which I am fine with. However, the color looks... fake. Like, a very pleasing green and really uniform. Note that the stone was sold to me as natural (not synthetic).


I know of the concept of gemstone coating to enhance color. Have we heard of this being done on emeralds?


Or what else could make the stone look so 'good'?


Thanks for any info,


Anne

Usually the 'too good' stones are synthetic. Coating the emerald would not remove the internal inclusions that are normally present. If the stone has no inclusions that typically means it is synthetic. Coated emeralds are very rare.

--Joshua

 

[serenitydiamonds]

Date: 12/10/2009 6:14:03 PM
Author: Sarahbear621
Hi Anne,


I''m not an expert but I believe it does. Emeralds can also be heated to help improve the color which will give it that uniform look as well.

Emeralds cannot be heated to improve the color.

--Joshua

 

[T L]

Date: 12/10/2009 6:37:16 PM
Author: serenitydiamonds

Date: 12/10/2009 11:12:57 AM
Author:anne_h
Hi,


I have just received my first piece of emerald jewelry (the appraisal is tomorrow).


In the mean time, a question... The emerald has some inclusions, which I am fine with. However, the color looks... fake. Like, a very pleasing green and really uniform. Note that the stone was sold to me as natural (not synthetic).


I know of the concept of gemstone coating to enhance color. Have we heard of this being done on emeralds?


Or what else could make the stone look so ''good''?


Thanks for any info,


Anne

Usually the ''too good'' stones are synthetic. Coating the emerald would not remove the internal inclusions that are normally present. If the stone has no inclusions that typically means it is synthetic. Coated emeralds are very rare.

--Joshua

Inclusion free stones are highly suspect of being synthetic, yes. However, they are making synthetic emeralds with inclusions to make them look more natural as well. Therefore, do not assume that a stone is natural just because it has inclusions.

 

[SB621]

Date: 12/10/2009 6:39:05 PM
Author: serenitydiamonds

Date: 12/10/2009 6:14:03 PM
Author: Sarahbear621
Hi Anne,


I''m not an expert but I believe it does. Emeralds can also be heated to help improve the color which will give it that uniform look as well.

Emeralds cannot be heated to improve the color.

--Joshua

Thanks Joshua- I thought they could, but I might be confusing them with other gemstones.

 

[serenitydiamonds]

Date: 12/10/2009 7:46:49 PM
Author: Sarahbear621

Date: 12/10/2009 6:39:05 PM

Author: serenitydiamonds

Date: 12/10/2009 6:14:03 PM

Author: Sarahbear621

Hi Anne,



I''m not an expert but I believe it does. Emeralds can also be heated to help improve the color which will give it that uniform look as well.

Emeralds cannot be heated to improve the color.


--Joshua

Thanks Joshua- I thought they could, but I might be confusing them with other gemstones.

No worries. Most emeralds contain small amounts of water and liquids inside... and when heated they will fracture and could explode, lol. Wouldn''t want that to happen to anyone. Rubies, Sapphires, Tanzanite are some gems that are heated.

--Joshua

 

[Nacre]

Tanzanites are not heat treated...

Green/brown Zoisite is heat treated to produce the blue colour called Tanzanite. Tanzanites are also showing on the market which have been coated (with I am assuming Be) but I am not certain on the coating material.

Emeralds can be Flux grown and Hydrothermally grown.

Both will show inclusions which can be mistaken for natural inclusions, seed plates and flux veils etc.

The most recognised natural inclusion in natural Emerald are the jagged three phase inclusions seen mostly in Columbian material. Synthetic Emeralds, to my knowledge, do not show these three phase inclusions, but they get better everyday with synthesis, so I could be wrong there!

Synthetic Emeralds as a rule show a lower RI, a lower SG and usually Flouresce strong red under LW and SW. Natural Emeralds are usually inert, or very weak under LW and SW.

If appraisal means certed, then you should know very soon anne_h!

I really hope things turn out okay for your stone. It''s always good to have a professional appraisal to keep your peace of mind though.

 

[serenitydiamonds]

Date: 12/10/2009 7:01:18 PM
Author: tourmaline_lover

Date: 12/10/2009 6:37:16 PM

Author: serenitydiamonds

Date: 12/10/2009 11:12:57 AM

Author:anne_h

Hi,



I have just received my first piece of emerald jewelry (the appraisal is tomorrow).



In the mean time, a question... The emerald has some inclusions, which I am fine with. However, the color looks... fake. Like, a very pleasing green and really uniform. Note that the stone was sold to me as natural (not synthetic).



I know of the concept of gemstone coating to enhance color. Have we heard of this being done on emeralds?



Or what else could make the stone look so ''good''?



Thanks for any info,



Anne

Usually the ''too good'' stones are synthetic. Coating the emerald would not remove the internal inclusions that are normally present. If the stone has no inclusions that typically means it is synthetic. Coated emeralds are very rare.


--Joshua

Inclusion free stones are highly suspect of being synthetic, yes. However, they are making synthetic emeralds with inclusions to make them look more natural as well. Therefore, do not assume that a stone is natural just because it has inclusions.

Yes, but be very suspect of a stone that has little or looks too good to be true.

--Joshua

 

[serenitydiamonds]

Date: 12/10/2009 10:13:29 PM
Author: Nacre
Tanzanites are not heat treated...


Green/brown Zoisite is heat treated to produce the blue colour called Tanzanite.

That is the definition of heat treatment. It is normal, and accepted among Tanzanite, but 99% is typically heated.

--Joshua

 

[Kismet]

Date: 12/11/2009 7:33:56 AM
Author: serenitydiamonds

Date: 12/10/2009 10:13:29 PM

Author: Nacre

Tanzanites are not heat treated...



Green/brown Zoisite is heat treated to produce the blue colour called Tanzanite.

That is the definition of heat treatment. It is normal, and accepted among Tanzanite, but 99% is typically heated.


--Joshua

I think Nacre is just being overly literal. He''s saying that the green/brown Zoisite is heated to BECOME Tanzanite and therefore the Tanzanite requires no (further) heating. If he''s selling his Tanzanite as all unheated I suppose it would be true in a sense but I would certainly classify it as deceptive advertising.

 

[serenitydiamonds]

Date: 12/11/2009 9:55:12 AM
Author: Kismet

Date: 12/11/2009 7:33:56 AM

Author: serenitydiamonds

Date: 12/10/2009 10:13:29 PM


Author: Nacre


Tanzanites are not heat treated...




Green/brown Zoisite is heat treated to produce the blue colour called Tanzanite.

That is the definition of heat treatment. It is normal, and accepted among Tanzanite, but 99% is typically heated.



--Joshua

I think Nacre is just being overly literal. He''s saying that the green/brown Zoisite is heated to BECOME Tanzanite and therefore the Tanzanite requires no (further) heating. If he''s selling his Tanzanite as all unheated I suppose it would be true in a sense but I would certainly classify it as deceptive advertising.

Yes, I understand that, and yes that is still heat treatment.

--Joshu

 

[LD]

Date: 12/10/2009 10:13:29 PM
Author: Nacre
Tanzanites are not heat treated...

Green/brown Zoisite is heat treated to produce the blue colour called Tanzanite. Tanzanites are also showing on the market which have been coated (with I am assuming Be) but I am not certain on the coating material.

Emeralds can be Flux grown and Hydrothermally grown.

Both will show inclusions which can be mistaken for natural inclusions, seed plates and flux veils etc.

The most recognised natural inclusion in natural Emerald are the jagged three phase inclusions seen mostly in Columbian material. Synthetic Emeralds, to my knowledge, do not show these three phase inclusions, but they get better everyday with synthesis, so I could be wrong there!

Synthetic Emeralds as a rule show a lower RI, a lower SG and usually Flouresce strong red under LW and SW. Natural Emeralds are usually inert, or very weak under LW and SW.

If appraisal means certed, then you should know very soon anne_h!

I really hope things turn out okay for your stone. It's always good to have a professional appraisal to keep your peace of mind though.

The coating is a cobalt coating and not BE diffusion that would permeate through the stone. The coating on Tanzanites is literally only on the surface and, thankfully, is not all that common.

You may find these interesting:

http://www.diamonds.net/news/NewsItem.aspx?ArticleID=23770
http://www.mayerandwatt.com/page/19

 

[anne_h]

Great news. I''ve had my appraisal by my usual reputed gemmologist and it''s all good!

The stone is natural. It''s been treated, but with colorless oil/resin. It has NOT been dyed or coated. The color I was so concerned looked fake is NATURAL (he was impressed also).

The inclusions indicate the stone is probably from Columbia (although I''m not super hung up on that).

The appraiser thinks I got an excellent deal for what I paid.

Of course the stone is not perfect, but I know it was not, and overall am happy with my purchase.

Yay!

Thanks everyone for all your info.

Anne

 

[T L]

DId he also indicate the level of treatment? Oil/resin filled emeralds can be lightly, moderately or heavily treated, and that does affect value.

 

[anne_h]

No, he didn''t specify level of treatment. I asked if I should be concerned about the treatment situation of the stone, and he said no. He just said colorless oil/resin treatments for emeralds is very normal and is industry accepted.

He said I should have no problem selling my ring for at least what I paid for it, if I ever wanted to.

A.

 

[T L]

Date: 12/11/2009 3:10:20 PM
Author: anne_h
No, he didn't specify level of treatment. I asked if I should be concerned about the treatment situation of the stone, and he said no. He just said colorless oil/resin treatments for emeralds is very normal and is industry accepted.

He said I should have no problem selling my ring for at least what I paid for it, if I ever wanted to.

A.

I would require the level of treatment in any emerald appraisal I was getting on a stone of high value. All other tings being equal (color, cut, carat weight), a lightly treated oiled emerald will be much more valuable than a highly treated resin filled one, in particular if that resin is not one of the newer accepted ones.

Emeralds are very tricky for gemologists to properly appraise. I would recommend sending it to a reputable gem lab like AIGS, for a true estimation of the treatment level. An appraiser can always assign a value to a stone, but if they do not know the level of treatment, or if they cannot even tell if it's oil or resin (doesn't sound like your appraiser did know which), then it's time to send it to a lab or a gemologist with better training on emeralds.

Even if oil/resin is accepted practice, some resins tend to dry out, or cause issues later on. It is important to know the kind of filler, and level of treatment when assigning a value to a stone. I personally disagree that all resins are acceptable. Not all, but some.

 

[anne_h]

Thanks.

I know what you mean, but this is not an investment stone or piece. And the ring itself was not terribly expensive (to me). So I personally am comfortable not pursuing further testing.

You are right - the gemmologist didn't indicate if it was oil or resin. But he felt confident it was colorless. I don't know what tests he was doing back there to be able to tell me that. lol. But I trust him.

Thanks again for your input.

Anne

PS - Since you seem to know a lot about emeralds, if/when I ever want to find a high-quality stone, who are some vendors you might recommend? I've seen Embassy Emeralds online...

 

[serenitydiamonds]

Date: 12/11/2009 4:59:00 PM
Author: anne_h
Thanks.


I know what you mean, but this is not an investment stone or piece. And the ring itself was not terribly expensive (to me). So I personally am comfortable not pursuing further testing.


You are right - the gemmologist didn''t indicate if it was oil or resin. But he felt confident it was colorless. I don''t know what tests he was doing back there to be able to tell me that. lol. But I trust him.


Thanks again for your input.


Anne


PS - Since you seem to know a lot about emeralds, if/when I ever want to find a high-quality stone, who are some vendors you might recommend? I''ve seen Embassy Emeralds online...

Colored oils are really obvious to detect in emeralds and for that reason they are very, very rare. I''m glad you found something wonderful for yourself. I''m sure I speak for a lot here, we''d like to see some pictures

--Joshua

 

[T L]

Date: 12/11/2009 4:59:00 PM
Author: anne_h
Thanks.

I know what you mean, but this is not an investment stone or piece. And the ring itself was not terribly expensive (to me). So I personally am comfortable not pursuing further testing.

You are right - the gemmologist didn''t indicate if it was oil or resin. But he felt confident it was colorless. I don''t know what tests he was doing back there to be able to tell me that. lol. But I trust him.

Thanks again for your input.

Anne

PS - Since you seem to know a lot about emeralds, if/when I ever want to find a high-quality stone, who are some vendors you might recommend? I''ve seen Embassy Emeralds online...

You''re very welcome.

I''ve never dealt with Embassy Emeralds, and I haven''t purchased an emerald in years since so many of them are treated, it turns me off. I''m sure there are some vendors that others can recommend.

 

[anne_h]

Okay, someone was asking for pics, so here goes.

In summary, my gemmologist concluded that the stone and its color is natural. There are some number of inclusions, which have been treated with colorless oil or resin. Which I am fine with.

Shot 1 is in natural daylight, no flash.
Shot 2 is same location, with flash.
Shot 3 is bathroom location, a little blurry, but shows those pretty sparkles from the diamond halo.

My finger is a size 4.5, but the ring is currently too large, which is why the prongs may appear off-center.

This ring is meant to be a statement piece, for parties and events, not for everyday. lol

If anyone has any questions, let me know!

Anne

 

[anne_h]

Shot 2:

 

[anne_h]

Shot 3:

 

[T L]

Anne,
To be honest, it''s so difficult to see your ring and the stone, it''s hard for me to comment on it. Do you know how to use the macro mode on your camera? I can see that it appears to be a very large stone in a halo, but other than that, it''s really hard to see details. I would love to see it more up close.

 

[anne_h]

Hi TL,

My husband has good camera with a macro lens, but it's currently being repaired. I had to use our ancient nearly-dead camera for the above pics. lol

At any rate, I'd say the ring is average quality, and the emerald, while large, is somewhat included and not ideally cut. But the color is nice, and overall it gives a good effect. I knew going in the stone was not perfect.

I'll post better pics if I can, but it may be awhile.

Thanks again for your interest!

Anne

 

[chrono]

I''m looking forward to the macro pictures; from what I can see...what a whopper of a stone and ring!

 

[Nacre]

Date: 12/11/2009 11:00:10 AM
Author: serenitydiamonds

Date: 12/11/2009 9:55:12 AM

Author: Kismet

Date: 12/11/2009 7:33:56 AM


Author: serenitydiamonds

Date: 12/10/2009 10:13:29 PM



Author: Nacre



Tanzanites are not heat treated...





Green/brown Zoisite is heat treated to produce the blue colour called Tanzanite.

That is the definition of heat treatment. It is normal, and accepted among Tanzanite, but 99% is typically heated.




--Joshua

I think Nacre is just being overly literal. He''s saying that the green/brown Zoisite is heated to BECOME Tanzanite and therefore the Tanzanite requires no (further) heating. If he''s selling his Tanzanite as all unheated I suppose it would be true in a sense but I would certainly classify it as deceptive advertising.

Yes, I understand that, and yes that is still heat treatment.


--Joshu

It is very important to be specific when it comes to treatments. The treatment of Zoisite is acceptable as it is permanent and it mimics nature.

You cannot say, therefor, that Tanzanite is heat treated to become blue. That is misleading and incorrect.

Most Tanzanite on the market has been heat treated. I have seen natural Tanzanite. Often they cut these stones to leave in the green Zoisite as well for rarity value.

And one more thing - I am a Gemmologist. I do not appreciate comments like this. "If he''s selling his Tanzanite as all unheated I suppose it would be true in a sense but I would certainly classify it as deceptive advertising."

Where is my advertising? Where am I selling Tanzanites again? I choose to remain avatar free and anonymous as I come to these forums to learn. If I have corrected you, build a bridge. This is a science and clients need to know facts about enhancements of gemstones.