Do Emeralds change color under "blacklights"?

[soberguy]

Will natural emeralds look different under blacklights? Was an incandescent "blacklight" bulb. My emerald looked yellowish to reddish (depending on where I set it near the bulb... reddish toward the top). It doesn't fluoresce like a few of the diamonds I have, just seems to change color... Bit odd, thought I'd ask lol!

 

[soberguy]

Like this: Fig 5:

http://www.ruby-sapphire.com/heat_seeker_uv_fluorescence.htm

 

[LD]

I'm not sure about yellow but certainly some of my Emeralds will fluoresce a pale pink. I have both treated and untreated Emeralds and both do this. I believe it's due to the Chromium(?) element that may be found in Emeralds. I'm sure TL can clarify because I always forget which element is responsible!

Here's a photo of an Alex and how red that looks (next to an Emerald) and below it is a better photo of the Emerald so you can compre the "redness"! The Emerald is one of mine that I believe is oiled:

 

[RockHugger]

As long as it doe ant glow bright red, I would guess it's ok. Bright red flor can mean synthetic. I recently purchased an emerald myself that glows a med pinkish color under uv, and it threw me off because the inclusions and such don't look synthetic. I researched it in my books a little and found that there are some Colombian emeralds that glow pink to med red. They are from the chivor mine in Colombia, and are colored more by chromium then vanadium. They are a blueish green color, instead of the yellow green color of Muzo emeralds.

My muzo emeralds have no flor.

Eta, by the pictures I think it's fine. If it lit up like the Alex I would be concerned, but the faint flor looks just like natural flor.

Eta again, oops that was another poster!

 

[T L]

I'm not sure about yellow but certainly some of my Emeralds will fluoresce a pale pink. I have both treated and untreated Emeralds and both do this. I believe it's due to the Chromium(?) element that may be found in Emeralds. I'm sure TL can clarify because I always forget which element is responsible!

Here's a photo of an Alex and how red that looks (next to an Emerald) and below it is a better photo of the Emerald so you can compre the "redness"! The Emerald is one of mine that I believe is oiled:

Yes, LD, an expert told me that chromium is the element that makes some emeralds fluoresce.

 

[LD]

I'm not sure about yellow but certainly some of my Emeralds will fluoresce a pale pink. I have both treated and untreated Emeralds and both do this. I believe it's due to the Chromium(?) element that may be found in Emeralds. I'm sure TL can clarify because I always forget which element is responsible!

Here's a photo of an Alex and how red that looks (next to an Emerald) and below it is a better photo of the Emerald so you can compre the "redness"! The Emerald is one of mine that I believe is oiled:

Yes, LD, an expert told me that chromium is the element that makes some emeralds fluoresce.

Thank you TL I was sure it was but I've got foggy brain at the mo!

Another question - I'm equally positive that while Emeralds with chromium typically hail from Muzo, there are other Emerald finds that also contain Chromium (i.e. Siberia?) etc, so seeing a faint fluor doesn't necessarily indicate locality, lack of or use of treatments etc. It simply indicates that the Emerald has some Chromium content???? Also, I believe that if an Emerald glows red under a backlight (typically and not 100%) it COULD signify that it's a synthetic????

 

[RockHugger]

LD, chromium emeralds don't come from muzo, they mainly come from the chivor mine in Colombia. Muzo emeralds are usually colored by vanadium. I say usually because of course, each mine can have variations. That's why muzo emeralds rarely florescence.

 

[soberguy]

The only difference I see TL is that the inclusions (and there are several, one that surfaces on the table...) are not a different color. They are the same color as the body.

 

[chrono]

I don't think an emerald will show much fluorescence; if it has chromium, then it will glow pinkish red under a Chelsea filter. A vanadium bearing emerald will show no reaction when viewed under the filter.

 

[soberguy]

I bought the same kind of bulb. Alexandrites and rubies are red, the emerald is very much pinkish compared to them. They kind of scream, the emerald does not.

 

[soberguy]

I can't get a picture with this bulb... if I take it in a room with other light, the color doesn't show up, in the dark, I get hardly anything at all. Is there a fluorescence tool I could buy? LD, what did you do?

 

[LD]

Not sure what bulb you're using?????

The easiest way is to get a small pocket UV penlight from Ebay - they're quite cheap. The way I then take pictures is to go into a room that is partially lit at one end and semi-dark in the other. In the semi dark part, I put the gem on the table and the UV pen shining onto it about 4-6 inches in front. I then take a photo with the camera sitting over the penlight (so it doesn't get in the picture).

Hope that helps.

 

[soberguy]

this is like and incandescent bulb, and it is not working for pictures lol! I'm going to look on Ebay right now.

 

[serenitydiamonds]

Natural emeralds should not fluoresce under black light, however they can under visible light slightly. Colombian Emeralds, or Type I Emeralds, contain Chromium primarily as an impurity with the possibility of trace amounts of Vanadium. Fine Colombian emeralds typically contain large amounts of Chromium, whether from Muzo or Chivor.

The chromium is what will cause them to glow a noticeable (but not too noticeable) red through a Chelsea filter, and fluoresce red under very bright visible light. Note, under visible light, not UV.

--Joshua

 

[serenitydiamonds]

LD, chromium emeralds don't come from muzo, they mainly come from the chivor mine in Colombia. Muzo emeralds are usually colored by vanadium. I say usually because of course, each mine can have variations. That's why muzo emeralds rarely florescence.

This is incorrect. All Colombian emeralds have large amounts of Chromium.

--Joshua

 

[soberguy]

then how do you explain LD's emerald?

 

[LD]

Thank you Joshua for clarifying. However, as Soberguy said, how do you explain my Emerald? It's definitely NOT synthetic. Admittedly the fluor you see with a UV is very very slight - you can see that in the photos. If I recall, when I last looked (and TL may remember this because she and I were discussing and doing experiments together at the time), under the Chelsea filter this Emerald and others I have, look a sort of peachy/pink/red - not a bright red.

Just as a FYI - some of my Emeralds show this slight pink under UV, others show none but all turn a form of red under the Chelsea filter.

 

[RockHugger]

LD, chromium emeralds don't come from muzo, they mainly come from the chivor mine in Colombia. Muzo emeralds are usually colored by vanadium. I say usually because of course, each mine can have variations. That's why muzo emeralds rarely florescence.

This is incorrect. All Colombian emeralds have large amounts of Chromium.

--Joshua

The GIA books tells me different. And why wouldn't emeralds fluor if they have chromium in them when chromium is a fluorescent element. I hear people say iron kicks back the fluor, but not all emeralds contain iron.

 

[serenitydiamonds]

Thank you Joshua for clarifying. However, as Soberguy said, how do you explain my Emerald? It's definitely NOT synthetic. Admittedly the fluor you see with a UV is very very slight - you can see that in the photos. If I recall, when I last looked (and TL may remember this because she and I were discussing and doing experiments together at the time), under the Chelsea filter this Emerald and others I have, look a sort of peachy/pink/red - not a bright red.

Just as a FYI - some of my Emeralds show this slight pink under UV, others show none but all turn a form of red under the Chelsea filter.

I'm not sure, has it been to a lab? Some treatments will fluoresce...

--Joshua

 

[serenitydiamonds]

LD, chromium emeralds don't come from muzo, they mainly come from the chivor mine in Colombia. Muzo emeralds are usually colored by vanadium. I say usually because of course, each mine can have variations. That's why muzo emeralds rarely florescence.

This is incorrect. All Colombian emeralds have large amounts of Chromium.

--Joshua

The GIA books tells me different. And why wouldn't emeralds fluor if they have chromium in them when chromium is a fluorescent element. I hear people say iron kicks back the fluor, but not all emeralds contain iron.

Do GIA books say they fluoresce under UV light (not visible), or that Muzo Emeralds don't contain Chromium? Which book are you referring to? There's a wonderful article in Rapaport Sep 2009 that goes into fair detail as to what impurities are present in Emeralds based on their location and how they are typed. All emeralds from Colombia contain Chromium, and large amounts of it. That is why Colombian's are prized for their color, and not other locations with different impurities.

--Joshua

 

[LD]

Thank you Joshua for clarifying. However, as Soberguy said, how do you explain my Emerald? It's definitely NOT synthetic. Admittedly the fluor you see with a UV is very very slight - you can see that in the photos. If I recall, when I last looked (and TL may remember this because she and I were discussing and doing experiments together at the time), under the Chelsea filter this Emerald and others I have, look a sort of peachy/pink/red - not a bright red.

Just as a FYI - some of my Emeralds show this slight pink under UV, others show none but all turn a form of red under the Chelsea filter.

I'm not sure, has it been to a lab? Some treatments will fluoresce...

--Joshua

This one hasn't been to a recognised lab - it was assessed by a valuer from the Birmingham Assay Office in the UK (who are highly qualified and the Assay Office does issue lab reports if you pay). It had some tests run on it but not extensive. I believe this Emerald is treated and it's highly included as you can see. It's not a great Emerald but has a lovely colour (hence the reason I bought it). I believe it to be Colombian and the colour (blue green) suggests as much. Can certain types of oiling fluoresce?

 

[serenitydiamonds]

Thank you Joshua for clarifying. However, as Soberguy said, how do you explain my Emerald? It's definitely NOT synthetic. Admittedly the fluor you see with a UV is very very slight - you can see that in the photos. If I recall, when I last looked (and TL may remember this because she and I were discussing and doing experiments together at the time), under the Chelsea filter this Emerald and others I have, look a sort of peachy/pink/red - not a bright red.

Just as a FYI - some of my Emeralds show this slight pink under UV, others show none but all turn a form of red under the Chelsea filter.

I'm not sure, has it been to a lab? Some treatments will fluoresce...

--Joshua

This one hasn't been to a recognised lab - it was assessed by a valuer from the Birmingham Assay Office in the UK (who are highly qualified and the Assay Office does issue lab reports if you pay). It had some tests run on it but not extensive. I believe this Emerald is treated and it's highly included as you can see. It's not a great Emerald but has a lovely colour (hence the reason I bought it). I believe it to be Colombian and the colour (blue green) suggests as much. Can certain types of oiling fluoresce?

Yes different treatments fluoresce in different ways. I use UV light to find (and/or avoid) certain types of fillers when buying. Another point is, how pure is your UV light? Does it have a set wavelength?
--Joshua

 

[LD]

No idea Joshua but the UV penlight has warnings all over it not to look in the light!!!

Let me take a few more picture of some of my Emeralds together and then you can see what you think.

 

[LD]

Ok - as you'll see from the time it's taken me these are REALLY rough and ready photos! So apologies in advance.

Explanation: The only Emerald out of this lot that seems to have any fluor is the pear. The others don't show any at all. I've included a Ruby that has strong fluor as a reference point only. The Emeralds are of differing quality but the darker green emerald cut one I believe has had no treatments (ever). This is a very blue/green in real life and although my Valuer believes it to be Colombian I'm pretty sure I remember something about it being Siberian (it's inherited and very old). The other two emerald cuts are definitely Colombian but don't fluoresce. The pear was sold as Colombian but I have nothing to verify providence.

Don't know if this tells you anything or nothing but maybe it indicates that the pear has had a treatment of some kind. Perfectly possible.

 

[soberguy]

Ok, the emerald I have put up a couple of times that I bought from the local Gem and Mineral show is the reddish pink one. The Zambian emerald is doing nothing. From what I have read that could be a result of the Vanadium vs Chromium... Pretty cool! From what I have found online red fluorescence DOES occur in natural emeralds, so I'm a bit confused...

 

[LD]

Just found this that indicates Emeralds may fluoresce under short wave UV but are inert under long wave. I have no idea whether the following is valid or not but thought it might be good for discussion. Interestingly, I've read a ton of conflicting statements on the web and this feels a bit like "what came first, the chicken or the egg" scenario!

How to identify the Emerald Gemstone
By: Erum Qureshi

Fluorescence

Another test to determine synthetics from natural emeralds is exposing it to Ultraviolet radiation (or UV rays). Synthetic emeralds transmit UV light more than natural emeralds. There are two common ultra-violet rays used for fluorescence. Those are short wave and long wave rays. Short-wave rays are ones with smaller wavelengths but with lighter frequencies and power in terms of penetration to the gemstone. Exposed to short-wave rays emeralds may show reddish fluorescence and when exposed to long-wave rays neutral fluorescence.

Alternatively the Chelsea Filter (an apparatus used by gemologists through which when an Emerald is viewed it appears red due to its chrome content) may be used to determine specific red fluorescence under short wave.


On the Ronald Ringsrud website it says:

" ........The Colombian emerald is blessed with a chemistry of color that is near perfect: mainly chromium, a little of vanadium and very little or no iron. It is the chromium that gives the green color as well as the red fluorescence. Vanadium creates the green emerald color but without the red fluorescence. Iron atoms in the emerald will blunt the red fluorescence and also make the green less pleasing by adding yellowish or bluish where it is not needed........"

 

[T L]

It's weird, because I have a Columbian emerald that does not fluoresce, but shows a weak red color under the chelsea filter.

 

[soberguy]

Oy lol! Well if nothing else, this is pretty exciting and interesting.

 

[serenitydiamonds]

They will fluoresce red, but under visible light, that is what Ron is talking about. If you shine very bright white light through a high quality emerald you will see red fluorescence. I think that's where the confusion lies. They do fluoresce red, but in visible (white) light. When you speak of fluorescence in gems, it doesn't just refer to UV, it can refer to any wavelength of light, visible, infrared, or UV.

Definition of fluorescence:
The emission of electromagnetic radiation, especially of visible light, stimulated in a substance by the absorption of incident radiation and persisting only as long as the stimulating radiation is continued.

The stimulating radiation can be any frequency. Some material fluoresce with UV (Diamonds), some with visible (Emeralds), etc.

http://gemologyproject.com/wiki/index.php?title=Emerald:
"The chromium will cause a fluorescence in natural daylight, but the iron content that is present in emeralds from certain locations dulls or totally suppresses that. Hence, there will be a different (not red) reaction to the Chelsea Filter."

If it's only a little red through the Chelsea that means you're Colombian is a good color. If it's a great color you'd see more red. If it's not red through the filter, there's no Chromium. If it's super glowy red it's probably synthetic.

--Joshua

 

[serenitydiamonds]

LD, yours responds so lightly to UV it could be treatment, impurities (since it's heavily included), etc, especially since your other emeralds don't react.

--Joshua