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hey ChronoDate: 2/16/2010 10:05:51 PM
Author: Chrono
Hey DF,
Welcome to CS.
Are you fussed about emerald treatment (oiled, filled, etc?).
Your choice of lab reports varies from GIA, GRS, Gubelin, AGL, AIGS, Burapha, Tokyo Gem Lab and many more.
No, the terminology for coloured gemstones is a little different and can vary depending on who you talk to. However, I still prefer the GIA coloured stone terminology to describe colour (tone, saturation and hue), clarity (type I, II, etc) and etc.
And yes, a 1 ct emerald usually looks big due to their specific gravity.
how much for a decent 1ct?Date: 2/16/2010 10:15:02 PM
Author: Gailey
How much moolah are you prepared to spend?
Welcome to the darkside! I warn you, you might never leave!
BG...she wants a emerald,but if emerald cost too much $$$ then i''ll go back to diamond.Date: 2/16/2010 10:52:57 PM
Author: Burberrygirl
Hey DF!Ditto to what the others said, have you considered Pala?
Yup, gem buying is not like painting by numbers that''s for sure. Lot of good advice in this thread DF.Date: 2/17/2010 10:15:34 PM
Author: Dancing Fire
thanks guysfor confusing mei better think this over.
Gailey...she don''t wanna read about emeralds,she just want one.Date: 2/17/2010 10:54:41 PM
Author: Gailey
Yup, gem buying is not like painting by numbers that''s for sure. Lot of good advice in this thread DF.Date: 2/17/2010 10:15:34 PM
Author: Dancing Fire
thanks guysfor confusing mei better think this over.
Might I suggest, while you are digesting it all, you consider getting Mrs DF a book:
Emeralds: A Passionate Guide
But I warn you, you may be on the hook for a stone larger than 1ct afterwards.
Epoxies and polymers are used on high quality emeralds as well. My emerald has epoxy, and I know one dealer that sold a very high quality emerald that was sued because he didn't disclose the epoxy filler to the client he sold it too, and this was many years ago as well (probably 12 to 15 years ago). Oils, resins, epoxies are routinely used on emeralds, and perhaps Joshua can correct me on this, but I don't believe African stones or other locations aside from Columbia are exempt for routine enhancement with these fillers.Date: 2/17/2010 2:48:12 PM
Author: jleb
One misconception about emeralds that people have is that clarity is as important as it is in diamonds. This is really not the case. When designing and cutting gemstones, the options range typically from emeralds on one side of the curve, and diamonds on the other. The design for emeralds is emphasizing the depth of color and glowing richness of the stone. For the emerald aficionado it is all about color. So the designs are usually step cut, sometimes with even the keel facet under the critical angle to darken the stone and pull the eye in. Diamonds on the other hand, are about colorlessness. I had a 3.5 carat L Vs1 diamond out of the mount... from the side it looked like a straw L.. face up, it looked like a G-H!! That's what a diamond cut does, removes as much of the color from the presentation as it can. (This is why diamonds are always graded from the side!).
The 'jardin' or inclusions in an emerald, therefore become part of the lore and mystique. The 'jardin' is composed of minute calcite crystals, 2 and 3 phase inclusions and imperfections in the crystal structure. These all add up to give an incredible glow and light play in the emerald. I have one that doesn't look very good on the macro close up, but in the hand it even glows in indirect light. This is what you want your jardin to do, is to counterpoint the depth and richness of color found in the cut, with sparkle and life when moved. So, it's not always a good idea to go for the 'cleanest' you can but a balance between richness of color and play of light.
Because the chromium atom has difficulty integrating with the crystal lattice in the emerald, stress fractures, voids, cracks and other surface reaching inclusions are present. Vanadium emeralds from Zambia for example, have just as much green, but not the issues with crystal structure. That's why Zambian and afghan emeralds require no treatment.
So Columbian emeralds are a pain. Most faceters just hate dealing with them, since the moment you've got a facet polished, it just collapses into this void or crack that opens up. Howls are heard to the heavens with dire imprecations. Fortunately faceting machines are too heavy to hurl across the room! We have to dip them in wax and soak them, otherwise you'll be seeing white aluminum oxide lines in your stone that nothing can get out. So, to turn these into something stable/marketable, treatment is required. The typical Columbian treatment is to have them oiled with cedarwood. Done in a vacuum at moderate temperatures, the stone is de-gassed(a day or two), dropped into the oil under vacuum and and then the vacuum released driving the oil into the stone. This is accepted industry and store practice. What the oil does is to penetrate the surface cracks and voids, pushing the air out and bridging the refractive index of the stone across the gap, so the imperfections are not seen.
For really bad emerald, epoxy's and polymers are used to fill the stone and hold it together. These are not always disclosed. For the most part these are non removable and not particularly popular. This is a big problem in the Columbian trade at the moment.
Zambian emeralds have a higher iron content in them than Columbian emeralds. This is why some of the Zambian emeralds have a bluish cast to them. Down the center of the crystal for example, they look deep blue green, where as Columbian emeralds do not. So be aware of the blue overtone when looking at the Columbian stones. The ones from Afghanistan do not have this issue, it seems limited to Zambian stones.
I can talk about this more and post pictures, but I don't want to overload the post, so let me know if you'd like the extras..
I just got bought this book from Barnes and Noble online store. There is a substantial discount and free shipping when I bought it from their site a few days ago.Date: 2/17/2010 10:54:41 PM
Author: Gailey
Yup, gem buying is not like painting by numbers that''s for sure. Lot of good advice in this thread DF.Date: 2/17/2010 10:15:34 PM
Author: Dancing Fire
thanks guysfor confusing mei better think this over.
Might I suggest, while you are digesting it all, you consider getting Mrs DF a book:
Emeralds: A Passionate Guide
But I warn you, you may be on the hook for a stone larger than 1ct afterwards.
Yes polymers, epoxies, and oils are used on all grades of emeralds, from the very poor, to the extremely expensive, no matter their source. Unfortunately 12-15 years ago none of this was disclosed as it should''ve been. Nowadays there are modern polymers that have excellent stability that many high tier customers are preferring over oil, since oil degrades gently over time. What separates the qualities of emeralds is the amount of treatment. African emeralds ''in general'' tend to be cleaner and lighter in saturation that Colombian, but can and definitely are treated also.Date: 3/31/2010 4:23:16 PM
Author: tourmaline_lover
Date: 2/17/2010 2:48:12 PM
Author: jleb
One misconception about emeralds that people have is that clarity is as important as it is in diamonds. This is really not the case. When designing and cutting gemstones, the options range typically from emeralds on one side of the curve, and diamonds on the other. The design for emeralds is emphasizing the depth of color and glowing richness of the stone. For the emerald aficionado it is all about color. So the designs are usually step cut, sometimes with even the keel facet under the critical angle to darken the stone and pull the eye in. Diamonds on the other hand, are about colorlessness. I had a 3.5 carat L Vs1 diamond out of the mount... from the side it looked like a straw L.. face up, it looked like a G-H!! That''s what a diamond cut does, removes as much of the color from the presentation as it can. (This is why diamonds are always graded from the side!).
The ''jardin'' or inclusions in an emerald, therefore become part of the lore and mystique. The ''jardin'' is composed of minute calcite crystals, 2 and 3 phase inclusions and imperfections in the crystal structure. These all add up to give an incredible glow and light play in the emerald. I have one that doesn''t look very good on the macro close up, but in the hand it even glows in indirect light. This is what you want your jardin to do, is to counterpoint the depth and richness of color found in the cut, with sparkle and life when moved. So, it''s not always a good idea to go for the ''cleanest'' you can but a balance between richness of color and play of light.
Because the chromium atom has difficulty integrating with the crystal lattice in the emerald, stress fractures, voids, cracks and other surface reaching inclusions are present. Vanadium emeralds from Zambia for example, have just as much green, but not the issues with crystal structure. That''s why Zambian and afghan emeralds require no treatment.
So Columbian emeralds are a pain. Most faceters just hate dealing with them, since the moment you''ve got a facet polished, it just collapses into this void or crack that opens up. Howls are heard to the heavens with dire imprecations. Fortunately faceting machines are too heavy to hurl across the room! We have to dip them in wax and soak them, otherwise you''ll be seeing white aluminum oxide lines in your stone that nothing can get out. So, to turn these into something stable/marketable, treatment is required. The typical Columbian treatment is to have them oiled with cedarwood. Done in a vacuum at moderate temperatures, the stone is de-gassed(a day or two), dropped into the oil under vacuum and and then the vacuum released driving the oil into the stone. This is accepted industry and store practice. What the oil does is to penetrate the surface cracks and voids, pushing the air out and bridging the refractive index of the stone across the gap, so the imperfections are not seen.
For really bad emerald, epoxy''s and polymers are used to fill the stone and hold it together. These are not always disclosed. For the most part these are non removable and not particularly popular. This is a big problem in the Columbian trade at the moment.
Zambian emeralds have a higher iron content in them than Columbian emeralds. This is why some of the Zambian emeralds have a bluish cast to them. Down the center of the crystal for example, they look deep blue green, where as Columbian emeralds do not. So be aware of the blue overtone when looking at the Columbian stones. The ones from Afghanistan do not have this issue, it seems limited to Zambian stones.
I can talk about this more and post pictures, but I don''t want to overload the post, so let me know if you''d like the extras..
Epoxies and polymers are used on high quality emeralds as well. My emerald has epoxy, and I know one dealer that sold a very high quality emerald that was sued because he didn''t disclose the epoxy filler to the client he sold it too, and this was many years ago as well (probably 12 to 15 years ago). Oils, resins, epoxies are routinely used on emeralds, and perhaps Joshua can correct me on this, but I don''t believe African stones or other locations aside from Columbia are exempt for routine enhancement with these fillers.