Color change gemstones

[mara82]

Are there any other color change gemstones other than alexandrite, color change garnet, color change sapphire, and zultanite?

 

[ma re]

CC spinel, CC tourmaline (both rare), probably some more but I can''t remember right now.

 

[LD]

Fluorite
Chameleon diamonds

 

[Lady_Disdain]

Date: 2/3/2010 6:22:55 AM
Author: LovingDiamonds
Fluorite
Chameleon diamonds

Aren''t chamaleon diamonds tenebrescent, though? I tought they changed colours after exposure to light/low heat (like a hackmanite), not according to wave length.

 

[zeolite]

The picture below shows, left to right:

CC sapphire, 2 matched CC tourmalines from the same crystal, CC spinel, two CC garnets, CC disapore. The picture is optimized for all gems together. Individual pictures would show a stronger change, for the tourmalines in particular.

 

[zeolite]

Below is another CC tourmaline, showing both lights at the same time (daylight fluorescent on one side, GE reveal incandescent bulbs on the other).

 

[zeolite]

Another view of same CC tourmaline. I have a 10 th CC garnet, from Wundanyi Kenya, that is finished, but I haven’t gotten around to photographing it yet.

 

[mara82]

Thanks everyone for your help. I''ve unintentionally have a color change collection just through buying stones I love. I so fare have all the stones I asked about but was wondering if there are any others out there I haven''t seen yet.

 

[LD]

Lady D - you''re right but chameleons change colour according to light only and don''t need heat as well (which is what all the others do) so I''d call them a colour changer! When I get mine out in the morning he''s green and after exposure to light becomes an orangey yellow.

Zeolite - how much colour correction have you used on those photos please?

 

[Kim Bruun]

There are also colour changing tanzanites, and colour shifting in blue and purple spinels does not seem too unusual. I have a grayish lavender spinel that shifts to a richer amethyst purple in tungsten light, and a grayish blue spinel that shifts to a grayish lavender.

 

[LD]

Date: 2/3/2010 1:46:06 PM
Author: Kim Bruun
There are also colour changing tanzanites, and colour shifting in blue and purple spinels does not seem too unusual. I have a grayish lavender spinel that shifts to a richer amethyst purple in tungsten light, and a grayish blue spinel that shifts to a grayish lavender.

Isn''t this just part of the pleochroism/trichroism? I''ve seen CC Tanzanites being sold and in truth they don''t colour change they just show two or three colours as you rotate the gem!

 

[Kim Bruun]

I don''t know - but I''ve seen tanzanites being sold online as colour change tanzanites. I remember one where I definitely did not get the impression that it was simply a question of pleochroism, but rather the gem appearing more pinkish under incandescent light. Sorry I can''t offer something more substantial.

 

[LD]

Date: 2/3/2010 2:17:24 PM
Author: Kim Bruun
I don''t know - but I''ve seen tanzanites being sold online as colour change tanzanites. I remember one where I definitely did not get the impression that it was simply a question of pleochroism, but rather the gem appearing more pinkish under incandescent light. Sorry I can''t offer something more substantial.

I think you''ll find this is a "marketing" ploy. Unless somebody would like to disagree, I''m pretty sure there''s no such thing as a colour change Tanzanite. It''s purely down to pleochroism/trichroism.

 

[chrono]

A true blue to purple colour change spinel isn’t all that common. The change is a lot stronger than the usual blue/violet spinel shift from outdoor to indoor. I have handled a few true blue to purple spinel colour changer and there’s no way they can be mistaken for the usual blue spinel colour shift. The shift is very dramatic and both colours are very strong and vivid. I have also not come across any colour change tanzanites but wonder if the vendor is trying to romanticize the pleochroism as a selling point to make it stand out among other tanzanites?

Zeolite,
How true to life are your pictures? Are the stones as saturated on both end of the colour changes/shifts?

 

[zeolite]

Date: 2/3/2010 2:11:53 PM
Author: LovingDiamonds

Date: 2/3/2010 1:46:06 PM
Author: Kim Bruun
There are also colour changing tanzanites, and colour shifting in blue and purple spinels does not seem too unusual. I have a grayish lavender spinel that shifts to a richer amethyst purple in tungsten light, and a grayish blue spinel that shifts to a grayish lavender.

Isn''t this just part of the pleochroism/trichroism? I''ve seen CC Tanzanites being sold and in truth they don''t colour change they just show two or three colours as you rotate the gem!

Pleochroism/trichroism is seeing different colors when viewing the gem in different directions in the same light.

Color change is seeing different colors when viewing the gem in the same direction in different types of light (daylight, incandescent)

 

[zeolite]

Date: 2/3/2010 2:47:07 PM
Author: LovingDiamonds

Date: 2/3/2010 2:17:24 PM
Author: Kim Bruun
I don''t know - but I''ve seen tanzanites being sold online as colour change tanzanites. I remember one where I definitely did not get the impression that it was simply a question of pleochroism, but rather the gem appearing more pinkish under incandescent light. Sorry I can''t offer something more substantial.

I think you''ll find this is a ''marketing'' ploy. Unless somebody would like to disagree, I''m pretty sure there''s no such thing as a colour change Tanzanite. It''s purely down to pleochroism/trichroism.

Yes, it is a marketing ploy. No, it is not pleochroism. See above. Yes, the color movement is real. Remember the two colors of my huge Asscher cut tanzanite, one in daylight, one in incandescent? The color movement is real. Yes, all tanzanites move somewhat more than most gems, as do amethysts and other purple gems.

I use the term "movement" as a term that indicates a difference in color, but not how much. All gems shift color somewhat in different light. The question is how much. That is difficult to accurately quantify.

Increasing levels of movement might be:

All gems in different light
Purple gems (see below)
Color shift gems (shifting to adjacent color on color wheel).
Color change gems (shifting to opposite side of wheel (ex.- red to green)

Purple gems: All purple gems will shift more strongly than other colors when viewed in different light sources (daylight , incandescent). This is a result of physics. In one sense, purple is not a spectral color. That is, purple is the only color than cannot be created by choosing a single wavelength of light.

See the CIE chart below. If you travel from the bottom left upward around the two rounded sides of the curve, you see numbers representing the increasing single light wavelength required to create that color. Notice that purple does not lie on the two curved sides. It is on the bottom straight line, and there is no wavelength number shown there. This is because purple can only be created by mixing both blue and red light.

Since incandescent and daylight contain different proportions or red and blue light, it is intuitively obvious that purple must show a stronger shift from one light source to another.

 

[LD]

Thank you Zeolite - but I''m confused - I''m pretty sure we''re saying the same thing though. I know what pleochroism is and that''s what causes the differences in colour (in the same light) and to my mind that''s being exploited and behind the marketing ploy of saying there''s a colour change.

As you say, nearly all gemstones will exhibit slightly different colours in different lighting conditions (especially purples and blues). I think we''re saying the same thing but in two different ways?

 

[zeolite]

LD: Zeolite - how much colour correction have you used on those photos please?

Chrono: How true to life are your pictures?

Most people use point and shoot cameras that have a single, non-removable lens. The file output is .jpg, which means there is very limited picture adjustment that can be done in a program like Photoshop.

I use a very expensive DSLR camera with a dedicated macro lens. Much more importantly, I can shoot in Canon Raw format. These files are about 4 times as large as a .jpg file. But I can radically change the exposure level, the color balance, the contrast and the color saturation in the Canon Raw converter, AFTER the picture is taken. This is an incredibly powerful tool. After the raw conversion, I can still go into Photoshop and make more adjustments on the TIFF file.

So to answer the question, I shoot the picture in Raw format, load the picture into my computer, place the gem with correct light source next to my monitor, and adjust the monitor picture until it matches the gem I am looking at. Yes, there is a lot of manipulation, but all manipulation is done to match reality, not to make it look better or more valuable.

The group pictures are not as accurate, because I must choose the one single color setting that represents the entire group. When I’m photographing only one gem, I can tweak the color to match that one gem, without worrying that it distorts the color of an adjacent gem.

Even with this computer expertise, it is impossible to match computer monitor phosphor colors to the actual gem. The actual gem always has much more contrast and often more color saturation than the monitor is capable of producing. So I can accurately say that every one of my gems looks better than my pictures show.

Chrono: Are the stones as saturated on both end of the colour changes/shifts? Garnets in particular, tend to have a weak, low saturation daylight color and a strong incandescent color. My new Wundanyi garnet is a very pastel blue-purple daylight color and a strong intense pink incandescent color.

 

[Lady_Disdain]

Date: 2/3/2010 1:40:13 PM
Author: LovingDiamonds
Lady D - you''re right but chameleons change colour according to light only and don''t need heat as well (which is what all the others do) so I''d call them a colour changer! When I get mine out in the morning he''s green and after exposure to light becomes an orangey yellow.

Zeolite - how much colour correction have you used on those photos please?

LD - I would say most tenebrescent gems don''t need heat (it just makes the change faster, as long as you don''t over do it). Neither my hackmanites nor my tugtupite need heat (I am afraid of heating them ,actually

), but my zircon does get a little heat sometimes, if he is sluggish.

 

[LD]

Date: 2/3/2010 4:13:20 PM
Author: Lady_Disdain

Date: 2/3/2010 1:40:13 PM
Author: LovingDiamonds
Lady D - you''re right but chameleons change colour according to light only and don''t need heat as well (which is what all the others do) so I''d call them a colour changer! When I get mine out in the morning he''s green and after exposure to light becomes an orangey yellow.

Zeolite - how much colour correction have you used on those photos please?

LD - I would say most tenebrescent gems don''t need heat (it just makes the change faster, as long as you don''t over do it). Neither my hackmanites nor my tugtupite need heat (I am afraid of heating them ,actually

), but my zircon does get a little heat sometimes, if he is sluggish.

I will confess that I''ve heated to a diamond to see the colour change! Held my breath ALLLLLLLLLLL the way but it was such fun!

 

[LD]

Date: 2/3/2010 4:07:29 PM
Author: zeolite

LD: Zeolite - how much colour correction have you used on those photos please?

Chrono: How true to life are your pictures?

Most people use point and shoot cameras that have a single, non-removable lens. The file output is .jpg, which means there is very limited picture adjustment that can be done in a program like Photoshop.

I use a very expensive DSLR camera with a dedicated macro lens. Much more importantly, I can shoot in Canon Raw format. These files are about 4 times as large as a .jpg file. But I can radically change the exposure level, the color balance, the contrast and the color saturation in the Canon Raw converter, AFTER the picture is taken. This is an incredibly powerful tool. After the raw conversion, I can still go into Photoshop and make more adjustments on the TIFF file.

So to answer the question, I shoot the picture in Raw format, load the picture into my computer, place the gem with correct light source next to my monitor, and adjust the monitor picture until it matches the gem I am looking at. Yes, there is a lot of manipulation, but all manipulation is done to match reality, not to make it look better or more valuable.

The group pictures are not as accurate, because I must choose the one single color setting that represents the entire group. When I’m photographing only one gem, I can tweak the color to match that one gem, without worrying that it distorts the color of an adjacent gem.

Even with this computer expertise, it is impossible to match computer monitor phosphor colors to the actual gem. The actual gem always has much more contrast and often more color saturation than the monitor is capable of producing. So I can accurately say that every one of my gems looks better than my pictures show.

Chrono: Are the stones as saturated on both end of the colour changes/shifts? Garnets in particular, tend to have a weak, low saturation daylight color and a strong incandescent color. My new Wundanyi garnet is a very pastel blue-purple daylight color and a strong intense pink incandescent color.

Thank you for your explanation. The reason I asked is because I own a number of (very good) Diaspore and also colour change Garnets and yours look almost too good to be true in the photo!!!! I''d love to see the photo before the messing around because that''s how the majority of us on here take photos. I''ve never even been near Photoshop (although it looks like good fun)!

 

[zeolite]

Date: 2/3/2010 3:29:58 PM
Author: LovingDiamonds
Thank you Zeolite - but I''m confused - I''m pretty sure we''re saying the same thing though. I know what pleochroism is and that''s what causes the differences in colour (in the same light) and to my mind that''s being exploited and behind the marketing ploy of saying there''s a colour change.

As you say, nearly all gemstones will exhibit slightly different colours in different lighting conditions (especially purples and blues). I think we''re saying the same thing but in two different ways?

Because of the optical properties of the color purple, all (purplish - not green or pink zoisite) tanzanites move more than other colors. The exploitation is that they don''t bother to tell you that all purple gemstones have this same stronger color movement.

 

[LD]

Date: 2/3/2010 4:28:03 PM
Author: zeolite

Date: 2/3/2010 3:29:58 PM
Author: LovingDiamonds
Thank you Zeolite - but I''m confused - I''m pretty sure we''re saying the same thing though. I know what pleochroism is and that''s what causes the differences in colour (in the same light) and to my mind that''s being exploited and behind the marketing ploy of saying there''s a colour change.

As you say, nearly all gemstones will exhibit slightly different colours in different lighting conditions (especially purples and blues). I think we''re saying the same thing but in two different ways?

Because of the optical properties of the color purple, all (purplish - not green or pink zoisite) tanzanites move more than other colors. The exploitation is that they don''t bother to tell you that all purple gemstones have this same stronger color movement.

So we ARE saying the same thing! Phew I thought I was losing the plot there!

 

[zeolite]

Date: 2/3/2010 4:25:23 PM
Author: LovingDiamonds

Date: 2/3/2010 4:07:29 PM
Author: zeolite

LD: Zeolite - how much colour correction have you used on those photos please?

Chrono: How true to life are your pictures?

Most people use point and shoot cameras that have a single, non-removable lens. The file output is .jpg, which means there is very limited picture adjustment that can be done in a program like Photoshop.

I use a very expensive DSLR camera with a dedicated macro lens. Much more importantly, I can shoot in Canon Raw format. These files are about 4 times as large as a .jpg file. But I can radically change the exposure level, the color balance, the contrast and the color saturation in the Canon Raw converter, AFTER the picture is taken. This is an incredibly powerful tool. After the raw conversion, I can still go into Photoshop and make more adjustments on the TIFF file.

So to answer the question, I shoot the picture in Raw format, load the picture into my computer, place the gem with correct light source next to my monitor, and adjust the monitor picture until it matches the gem I am looking at. Yes, there is a lot of manipulation, but all manipulation is done to match reality, not to make it look better or more valuable.

The group pictures are not as accurate, because I must choose the one single color setting that represents the entire group. When I’m photographing only one gem, I can tweak the color to match that one gem, without worrying that it distorts the color of an adjacent gem.

Even with this computer expertise, it is impossible to match computer monitor phosphor colors to the actual gem. The actual gem always has much more contrast and often more color saturation than the monitor is capable of producing. So I can accurately say that every one of my gems looks better than my pictures show.

Chrono: Are the stones as saturated on both end of the colour changes/shifts? Garnets in particular, tend to have a weak, low saturation daylight color and a strong incandescent color. My new Wundanyi garnet is a very pastel blue-purple daylight color and a strong intense pink incandescent color.

Thank you for your explanation. The reason I asked is because I own a number of (very good) Diaspore and also colour change Garnets and yours look almost too good to be true in the photo!!!! I''d love to see the photo before the messing around because that''s how the majority of us on here take photos. I''ve never even been near Photoshop (although it looks like good fun)!

The ability to cheat in CC gem photography is unlimited. I can take a ruby and make it green in photoshop. Besides manipulating the picture, a careful choice of light sources can exaggerate the color change. The change is actual, but some could consider it cheating.

A purist could state that only sunlight and candle light is the true measure of color change. The seller of my Wundanyi garnet used a (bluish) white LED penlight to exaggerate the color change.

Since my computer CRT monitor is heavy and inside, I have to use a fluorescent light as a stand-in for daylight when I''m comparing the actual gem to my computer monitor when adjusting the color. Daylight fluorescent gives a stronger than daylight color change, while excella fluorescent is about as true to daylight as you can get, using fluorescent tubes, I''ve always be very straightforward as to the light sources I use in my pictures.

Below are two rows of my CC garnets. The top row shows daylight fluorescent, and bottom, incandescent (picture name-dfinc)

 

[zeolite]

The next picture, top row shows excella fluorescent, and bottom, incandescent (picture name-excellainc).

If my CC gems seem good, that is partly a result of 25 years of gem selection of millions of gems offered at Tucson, plus buying the estate of a gem connoisseur with an extremely good eye for CC gems.

 

[LD]

What''s interesting to me (and I own many colour change gemstones) is that your top photographs look "real" and I can identify with the colours I''m seeing. The bottom rows in both look unnatural somehow. A bit too super-enhanced. I''m sure they''re not and I''m not criticising at all because it''s lovely (and very interesting) to see the same gems photographed in different lighting conditions and using different techniques. Do you also do something (particularly in the bottom photos) to enhance the look of the gem? I don''t quite know what I mean, but perhaps sharpen them up????? Does that make sense?

 

[zeolite]

Date: 2/3/2010 5:10:22 PM
Author: LovingDiamonds
What''s interesting to me (and I own many colour change gemstones) is that your top photographs look ''real'' and I can identify with the colours I''m seeing. The bottom rows in both look unnatural somehow. A bit too super-enhanced. I''m sure they''re not and I''m not criticising at all because it''s lovely (and very interesting) to see the same gems photographed in different lighting conditions and using different techniques. Do you also do something (particularly in the bottom photos) to enhance the look of the gem? I don''t quite know what I mean, but perhaps sharpen them up????? Does that make sense?

As I said, I use GE Reveal incandescent bulbs. From the gelighting.com website:

What Makes GE Reveal® Incandescent Bulbs Different
GE Reveal bulbs make colors "pop" in a way they don''t with standard incandescent bulbs.
Why? The rare earth element neodymium that''s in the glass. (It''s what gives these bulbs their distinctive blue color when unlit.) When these bulbs are lit, the neodymium provides a pure, clean light by filtering out much of the dulling yellow cast common from ordinary light bulbs.

Throw out your trashy yellow bulbs and use these. No, no special sharpening.