Unexplained phenomenon that I hope some of you can explain

[Debbie K]

This topic is going to sound strange, but bear with me. I know nothing about the sun, astrophysics, astronomy or any of the related sciences. Sorry for the long post; I'm a longtime lurker here. Have in interest in sunspots and the solar minimum so have been checking in here for quite a while.

I am writing to report a phenomenon that I believe has something to do with the sun's activity; more specifically, solar flares. To give all of you a little background, I'm by way of being a gemologist (hands on variety) with some GIA training. I carve gemstones and do a little faceting. I came up with a different and innovative way of faceting a gemstone, and in the case I'm referencing, a piece of clear Arkansas quartz, in a way that would improve it's refractive index.

In the course of looking at it, out in the sunshine, I noticed an extremely peculiar phenomenon. On occasions, the white, clear stone would turn pinkish and then purple. I thought at first it might be the angle of the sun, the stone heating up; but it happened on hot or cool days and the color would come, go, and come again. I also tried it with standardly cut quartz (very faint reaction) and natural quartz crystals (no effect).

For those of you who do not know, amethyst, the purple variety of quartz, derives it's color from what are called “color centers” which is a distortion in the clear crystal lattice which is caused by gamma radiation. It occurred to me that perhaps the same thing is happening, on a much smaller level, in these gemstones.

I've discussed this with some other gemologists and mineralogists who were as mystified by this as I am. If I hadn't had another person observe it, too, I would have questioned my vision and observation. Unfortunately, I didn't record my observations as to the day and time. The other observer had cataract lens surgery, which means they were looking at it thru a UV filter (yes, the lenses have UV filters!) and I haven't and we were both able to see the colors.

Today, I took some of them outside as it is a pretty, sunny day (in Houston, Texas) and watched. No reaction for about 30 minutes, but at around 2:00 p.m. CST the color began to change and by 2:07 the color had gone from pale pink to pink to purple. It was no where near as intense as it was on prior (unknown) occasions, but noticeable nevertheless. At about 2:07 it reached maximum purple color and then slowly began to fade to pink then yellowish then colorless at 2:14.

I came on this website and saw that a small solar flare occurred about 47 minutes before I observed the phenomenon of the color change in my stone. I don't know how long it takes for radiation from a flare to reach earth and I'm hoping that someone can tell me if it's feasible that there is any correlation.

Unfortunately, a camera does not record the color. The mineralogist friend explained to me that it probably couldn't as it most cameras only register in certain ranges. I have tried to duplicate the color by exposure to infrared and long and short wave UV without any luck. I don't have access to anything to expose it to X-ray or gamma radiation, so can't test for that.

I know correlation doesn't necessarily translate to causation, but there is something odd going on. It seems to me that I may have inadvertently made some kind of device that registers something (?) coming from the sun. It occurs to me that if it does it may have some kind of practical application for someone somewhere. Do any of you know anyone who might have any interest in anything of this kind? It isn't a standard cut stone, so it doesn't really work with the regularly cut ones. I haven't tried the cut on anything but quartz as I was dealing with it's particular refractive index and making changes to try to shift it. Any input welcome.

[helios]

18 hours ago, Debbie K said:

I came on this website and saw that a small solar flare occurred about 47 minutes before I observed the phenomenon of the color change in my stone. I don't know how long it takes for radiation from a flare to reach earth and I'm hoping that someone can tell me if it's feasible that there is any correlation.

The xray radiation from a flare reaches earth in less than 1 second after it is detected by the GOES satellite.
Solar flares emit mostly EUV and xray radiation, both of which do normally not pass through the atmosphere, particularly in the small flares that we had in the past years.
So any change in light spectrum on ground level can almost only be explained by atmospheric phenomena.

Perhaps a spectroscope can help identify the change in color. I found some cheap gemology spectroscopes on ebay, but I have no idea about the quality of those.

[Debbie K]

Helios:

Thank you for your response. The time reflected on the solar activity chart is the time that it is detected by the GOES satellite, not the time it actually occurred? Then the one second arrival time makes perfect sense.

I have two spectroscopes; one is a diffraction grating and the other a prism. Neither will do anything to help in this particular case as they are only good at identifying particular elements with any degree of accuracy, and it wouldn't apply in this case as clear quartz crystal has no discernible elements, at least with that type of equipment. A Raman or FTR spectrometer might tell us a little more, but doubtful.

Do you have any idea about what kind of atmospheric phenomena could possibly account for what I am observing? I am not the only person mystified by what is occurring; this isn't a normal or even a previously commented upon reaction as far as I can tell. I've been reading all I can about quartz and crystal on the mineralogical and gemological sites that I can find to try to explain it without any luck. Color shift in crystals is by no means unusual, but is very unusual in any kind of quartz. It is observable in certain amethyst; there is a slight color shift from red-purple to blue-purple depending on the type of light; incandescent or fluorescent. Could atmospheric conditions change the incandescent light to the more selective and closer to UV fluorescent light? Since the color in amethyst is the result of the crystal's lattice deformation the change in color would have to be the result of type of light and the way it interfaces with the structure, not a chemical or elemental cause.

Like I say, I know not much about the sun and the different types of energy it emits, which is why I'm asking here. Thanks again for your reply!

[Archmonoth]

26 minutes ago, Debbie K said:

Since the color in amethyst is the result of the crystal's lattice deformation the change in color would have to be the result of type of light and the way it interfaces with the structure, not a chemical or elemental cause.

Like I say, I know not much about the sun and the different types of energy it emits, which is why I'm asking here. Thanks again for your reply!

 

Light bouncing around in minerals can change color based on temp, as well as conductivity. Some minerals increase in conductivity as they retain heat.

 

The thermal properties in quartz can be described as a conductive resistor, the amount of resistance can produce color. The wiki article on quartz describes pink/red as rare. The source of color is due to a microscopic fiber Dumortierite - Wikipedia 

 

The atmosphere is like a lens, and many of the attributes of light can be seen. Larger systems have MORE parts, and their complexity can be higher than the small system of a quartz prism. Your mystery might be a single property, or many properties of light acting in a different system. 

 

Perhaps this helps dim the light of your mystery a little. 

Edited August 3, 2021 by Archmonoth

[Debbie K]

Archmonoth:

Thank you so much for your reply. Is there anywhere you could recommend that I could find out more information about resistance and the color that it can cause? I did wonder about heat perhaps being a factor, not so much conductivity. The cut that I came up with bounces the light around inside the stone to a large degree; the result of trying to achieve a cut on quartz that would have the appearance of one with a far higher refractive index. Perhaps the retention of light, heat and conductivity is what is causing it.

Rose quartz almost invariably is "sleepy"; even the best of the best from Madagascar is not ever truly "clear"; the dumortierite inclusions interfere with the light which results in a scattering effect, be it ever so slight.  I will check and see if there is any dumortierite listed as any of the minerals that can exist in Arkansas quartz. There was a man who did a lot of irradiation experiments on various quartz back in the '70's; with the clear quartz from Arkansas it almost invariably turned gray, brown or black.

No, it doesn't dim the light, just makes me more determined to get to the bottom of it!

[helios]

There are two different types of immission from the sun shown on this page, which have different latencies.
But I think neither of those have anything to do with your discovery.

Clouds and aerosols can cause a change in the light spectrum very abruptly. A change in the UV spectrum is not necessarily noticed by eye.

I don't know enough about gemology to help finding an explanation for the phenomena. Perhaps you can try to block UV light (for example with a sheet of non-quartz-glass) and see if the color will change.

[Debbie K]

The color still changes under Tuftex polycarb roofing, which supposedly blocks UV light. The color change is only observable outside; when coming through a Pella window, it doesn't happen, and it's supposed to have 83% UV blocking.

I will take your advice, helios, and look for a UV blocking lens or glass and see what happens. I need a pair of cheap sunglasses, I guess.

[HalfFeralHuman]

I've got a thought here, and it's probably a long-shot, but it sounds like a long-shot is all anyone's going to have for what you're describing. My thought is that the effect is not caused by photons of light, rather it's caused by magnetic perturbations (which solar winds would cause). I'm thinking that what you're seeing is a side of the piezoelectric effect that gives crystal oscillators a stable and predictable frequency. We could be getting particular frequencies of magnetic pulsations that correspond to the resonant frequency, or a harmonic of the resonant frequency of the crystal you're observing this in. The result could be a temporary change in density or electron configuration, giving the effect you're describing.

Recently I've been looking into a somewhat odd phenomenon in geomagnetic field changes, not in the average field strengths as shown by most magnetometers, rather in faster oscillations in the geomagnetic field. I wanted to know if they're connected to the sun or other phenomena, and at present my best guess is that the cause could be related to solar activity, specifically either resonating magnetic reconfigurations in the solar winds or between objects in our solar system. Could is an important word here... it could be a geological, or could be... well anything, I don't have much to go on other than noticing a corresponding increase in wave patterns across the sun that do not seem to rotate with it, but that could be a red-herring. 

Anyway, one particular observatory I've been following is the Kiruna observatory in Sweden. Other than the usual magnetometer graphs, they also have a histogram type chart of ultra-low frequency magnetic oscillations (<=5 Hz, referred to as pulsations). What's particularly caught my attention are periods of harmonic oscillation that have been increasing in intensity, duration and quantity of detected harmonic bands. The fundamental frequency of these oscillations are too low for any explanation I've come across so far. One example ended today (2021-08-03) at around 13:45 UTC. The chart in question is the second at the bottom of the page.

While these kind of frequencies aren't likely to set up any relevant oscillations in your crystal, a much higher order harmonic of this potentially could, as could higher frequency oscillations that either aren't being measured or aren't being published as far as I know. I wonder if there's any correlation between patterns on that chart and your observations?

I'd be curious if anyone else has anything to add to add to what I'm seeing too.

[Debbie K]

HalfFeralHuman:

Really interesting post! I have a friend (a mineralogist who specialized in crystals, her doctoral thesis was on quartz, how lucky am I!) and she would probably be able to tell me if high frequency (or low, for that matter) magnetic oscillations could affect the structure of quartz. I need to re-read all of the information about the piezoelectric effects in quartz and if it actually displaces electrons in a way that could effect color. My friend was of the opinion that infrared light was a possible explanation, but subsequent exposure to an infrared light did not duplicate the effect.

I also need to facet more stones and keep careful notes about the axis' involved. From a gem-cutting point of view, you do the cut that provides you with maximum yield with the best color (a pointless thing when dealing with clear quartz), so I didn't really pay attention to the crystal orientation at the time. I could probably closely approximate the c-axis with a polariscope, but I seriously doubt that it will line up either horizontally or perpendicularly to the table of the stone. Some of the stones (I have about 7 clear quartz cut with this cut) react far more than others.

However, the color change does not occur to any observable degree indoors, so it seems to be light (or heat, or conductivity) that effects it. I took it outside around the time you're talking about and for the first time it appeared to turn to a yellowish green, but it didn't last for long. No pink or purple today. As it is high summer here, I don't stay outside too long. I cannot predict when it will occur; in the past it would be anytime roughly between 10 a.m. to 4 p.m., because those are the times when the sunlight isn't blocked by trees, and it occurs only occasionally. Most of the time it's just an unremarkable piece of clear quartz. One time the color was that of a hot pink sapphire and then deepened to a medium purple color. Very strange; and on that particular day the color was observable even when the piece was in the shade.

As a result of this discussion, I am going to make many more tests and keep a written log of anything I see and the time it occurs. I'm determined to figure this out if I can, and all of you have given me different directions to investigate and I'm truly grateful.

[Drax Spacex]

On 8/2/2021 at 3:55 PM, Debbie K said:

Unfortunately, a camera does not record the color. The mineralogist friend explained to me that it probably couldn't as it most cameras only register in certain ranges. 

Most CCD camera sensors can detect all wavelengths the visible light spectrum.  Perhaps you could apply post-processing on your photographs to increase color saturation (being careful not to introducing any artifacts you do not also see).

[HalfFeralHuman]

Debbie K:

I'd be really interested to know where you get to with that. I'm really intrigued by this post, and if there really is something here it strikes me that there could actually be something useable in this.

[Debbie K]

Drax Spacex:

The camera on my Samsung Galaxy 5 is supposed to be a CMOS. I don't know if that makes any difference, as I don't understand the difference between the two, and to be honest, never knew til now what kind my phone had. Unfortunately, I don't know how to do any post-processing, either.

HalfFeralHuman:

Me, too! That's why I'm trying to figure out what is triggering this reaction, because I think it could be useful somehow. It's certainly registering something, but unfortunately it may be a combination of many things, as Archmonoth said, and it may be too complex to figure out just exactly is happening.

[Ann-Kristin Bjørby]

I have no idea of what this is and have never been here before and saw ure post, I wonder if you have measured/timed it up against the Schumann Resonance? That has to do with high frequency energy hitting earth and is one of those invisible impacts we encounter a lot of these days. 
This is a link to Tomsk where they have a laboratory that measures it if you want to check it out. Anyway, I hope you find out what it is, I find your story so fascinating.

http://sosrff.tsu.ru/?page_id=7

[helios]

A comment regarding the suggestions concerning magnetic perturbations and Schumann resonances:
Those effects are almost impossible to detect in urban areas, and thus can almost certainly be ruled out as a cause for the described color change. Artificial emissions are much stronger than those natural sources.

Magnetic perturbations:
To detect fluctuations in the geomagnetic field, very sensitive magnetometers are required, placed far away from electrical conductors and other metal constructions.
From a description of such a sensor: http://www.reeve.com/SAMDescription.htm
"Because of the magnetometer sensor sensitivity to both temperature and man-made disturbances, it normally is installed at a remote location and buried in the ground."

Schumann resonances:
Same with the Schumann frequencies. Even in the middle of a desert, it requires a lot of effort to detect those at a reasonable SNR. The antenna needs to be far away from power grids, otherwise EM noise is by several magnitudes stronger than the Schumann-resonances. Here's a description of required equipment to detect those:
http://www.vlf.it/inductor/inductor.htm
Additionally, changes in amplitude happen over hours, not minutes.

[Newbie]

Hi Debbie! 

I know sunlight can cause certain gemstones/minerals to fade. Quartz crystals being one example, particularly the pink and citrine varieties, probably amythest too. Sunlight then compromises the lattice arrangements breaking down the colour centres.

I know that quartz does not exhibit pleochroism, that is, it doesn't show different colours when viewed from different angles.

Your observation of the changing colours are the opposite to what would be expected.

When you took more gemstones out into the sunlight the second time did they all react exactly the same way, did they all change from pink to purple and then change back again?

Were all the gemstones cut in exactly the same way ie were the facets the same or similar?

Have you tested quartz from other areas?

Piezoelectricity, (an accumulation of charge) is stored in quartz crystals which have been subjected to mechanical stress. I suppose cutting of the gemstones may cause sufficient stress. This stress can cause Ions to be displaced. Maybe strong sunlight has an effect on these ions. Manifested in a change in colour? I don't know! Nothing I have read indicates this but when people are working with quartz it's usually indoors in artificial light.

Very intriguing! 

Newbie

 

[Debbie K]

Helios:

Thanks for this information. Since I do live in an urban area, it can be assumed that there would be a lot of interference.

Newbie:

Yes, many gemstones that rely on their color due to color centers, most notably kunzite, maxixe beryl, imperial topaz and amethyst can and do fade upon exposure to light. Colored quartz can and often does exhibit dichroism, but is often very faint.

I spent quite a bit of time coming up with an innovative way to facet a stone, specifically quartz (based on its specific refractive index as this varies significantly from stone to stone), to increase it's diffraction. I shifted angles in a way that is not done on standard cuts to try to increase the "fire" that is observable in stones with higher refractive indexes like cz, garnet or diamond. I'm not a truly a faceter but I had a theory that quartz appearance could be dramatically increased with a different cut. I've cut about 13 quartz by this method; nine from clear quartz. All of them react, some of them more than others, which I attribute to differing angles as I was experimenting. A standard round brilliant cut quartz will also show a very, very faint reaction, so faint that it could be easily overlooked. All of the stones that I cut had a much stronger reaction.

Since I'm not a faceter, and quartz in particular can cause "issues" (subsurface damage and polishing problems) each stone I cut usually takes me at least a day. This explains the paucity of my test pieces, as I'm usually doing other things.

The reaction seems to be first a yellowish hue, then pink, then purple, back to pink and then to yellow and finally back to white. I do so wish that I could get photographs of it because the human eye is so subjective and uncorroborated. The first time I observed it, I thought that it was the consequence of looking at a white or bright object and the effect it has on the retina. I have subsequently placed the stones on black as to not "burn" my eye and only look at them occasionally to diminish this effect, as the stones themselves are pretty bright.

I know some of the quartz was from Arkansas (collected by a friend), but some of the other probably came from South America, especially the citrine and amethyst. Lapidary people like me don't care so much about the origin of a cheap material like quartz so my record keeping in this regard is practically nil. It is really difficult to know the true origin of any mineral unless it is self-collected, as folks in the gem/rock trade commonly misrepresent locales, either intentionally or accidentally. I think it would be a good idea to try stones from different locations, but during Covid it would be a challenge.

I think what I've done, accidentally, is devised some way of accumulating or collimating light in a crystal in a way that hasn't been done before, at least not on a consistent basis. I don't know if this is increasing or decreasing its conductivity or resistance or shifting the light in some odd way that it's more sensitive to fluctuations of infrared, visible or UV light. I was hoping that smarter people than me would be able to say "Oh, yes! Very well known and common effect. See so and so for an explanation". I know a lot about gemstones, carving, art and other things but next to nothing about crystallography, light and energy. So any and all help is welcome and I thank all of you for your patience and input.

[Archmonoth]

43 minutes ago, Debbie K said:

I was hoping that smarter people than me would be able to say "Oh, yes! Very well known and common effect. See so and so for an explanation". I know a lot about gemstones, carving, art and other things but next to nothing about crystallography, light and energy. So any and all help is welcome and I thank all of you for your patience and input.

 

I don't have experience cutting rocks/crystals. I do know the crystalline process (pressure and time) will create many exotic and interesting formations.  Much of my knowledge comes from conversation, then exploring the idea. My favorite jumping off point is Wikipedia, since there are many sources of knowledge for a particular topic. 

 

Looking into crystalline structures, I found something called the Miller indices, perhaps you are aware of them? (about 1/2 down the page on the right side: Crystal structure - Wikipedia)

 

Cutting crystalline structures can create vertices which are cubic, perovskite, or some other configuration which can affect the bouncing light within the crystal. Sapphires for example can handle bouncing gamma radiation, and this quality is useful for powerful lasers. 

 

The complex world of chemistry travels into the world of math and geometry, especially when dealing with bouncing light.  For me, the keystone for understanding light was the Inverse Square Law; the basic idea is that light decays over the distant from its source. 

 

As light enters the quartz crystal, it is entering a new system, with new boundaries. 

 

Imagine your crystal like a triangle, or pyramid. Light is like a small bug, traveling at an angle, bouncing every time it hits an edge. However the edge isn't absolutely smooth; with every bounce, and distance traveled reduces the energy amount of the light bug. So as it bounces in the freshly cut triangle/pyramid, light emits, until a new equilibrium is found, and the light bug finishes bouncing around. The light you see is sun light exiting the quartz after it bounces around. 

 

Perhaps try cutting the already cut quartz again? 

Edited August 4, 2021 by Archmonoth

[Debbie K]

Archmonoth:

To further complicate matters, all quartz crystals are chiral, which means they are left or right handed. Natural crystals, especially the Brazilian variety, are often twinned, which means they can be both left and right handed in the same crystal. You can determine the chirality and whether or not it is twinned with a polariscope (this took a deep dive in Internet purgatory to find, finally in a textbook in the Gutenberg project from 1896), but it usually requires a polished stone to find an interference signature to be able to see. The prismatic colors will be reversed depending on their handedness and in twinning, the colors will flip. Fun thing to do on a rainy day.

In addition, quartz behaves as a singly refractive stone when viewed down its C-axis, and doubly refractive along the A or B sides. Another layer of complexity.

Quartz in the tetragonal family, and primarily trigonal, though I believe some can be rhombohedral. Unfortunately, the Miller indices are for cubic material, and you are flattering me to think that I could be begin to understand it, anyway. I understand the principle of Snell's law, which is as far as most gemologists ever get. I understand the principle of refraction and know the light is bent in a relatively predictable way when passing through different things.

I don't quite understand the suggestion regarding cutting the already cut stone again; are you of the opinion that the effect is something intrinsic in the stone itself and it would behave this way regardless of the cut and cut it in a standard way and seeing if the phenomenon persists? As I've already cut 9 stones out of different material on different axis and all of it behaves this way to varying degrees, I have to conclude that it's the cut.

Thanks for the reference to the Inverse square law. I'm going to be thinking about this for a while...

[3gMike]

Hi Debbie,

You mentioned that the observed effect shifted from a yellowish hue to pink then a deeper purple over a period of about 7 minutes, then went back to yellow over another period of 7 minutes. That suggests to me that the crystal was effectively acting like a moving bandpass filter over the spectral range yellow (580nm) to deep red (680nm) then back again. Refer to colour spectrum in dispersion section of this website https://www.gemsociety.org/article/optics-gemology/

Without knowing the detail of how you have faceted the crystal it is difficult to give a precise answer, but I suspect that cut faces were essentially acting as a prism, or possibly a pair of prisms, and the colour changed as the angle of incidence of the sun's rays changed. 

I'm not sure why you were unable to capture this on a camera, but it is most likely due to the dynamic range of the camera exposure control, and the colours in the crystal being relatively dim compared to ambient light.

 

[Debbie K]

3gMike:

Yes, the color shift does seem to be following a spectrum. Today was an overcast day, but I took them outside anyway to try to see if there was any effect. The color went from yellow to yellow-green then green several times, and once went to a bluish green. The shift takes place over the course of about 5 minutes from yellow to green and about the same amount of time to fade back to a yellowish color, and sometimes as little as 5 minutes to go back and forth. These stones are not remaining static, as I pick them up occasionally to move them to different background and it does not effect the color, so I don't think the angle of incidence is a factor.

I think it must be some sort of atmospheric effect that is contributing a great deal to what is occurring as 2 days ago, a partly sunny day, the range was yellow to purple and today, on a cloudy day, it went the other way, from yellow to greenish-blue.

I also realized I had some welding goggles that are rated to UV400 and I held them over the stones to see if it affected the observable color. They didn't. They claim to block visible and UVa, but not UVb or UVc. Both the long and short wave fluorescent lights I have didn't show any reaction, but I don't know their exact range.

And, I again tried to get pictures, especially to capture the lovely mint green, but again with no luck. I fiddled around with different settings (extremely limited options; my phone is really old) to see if made any difference but it didn't. It was so odd to see the image on the screen not reflecting what I was seeing right next to it.

 

[Newbie]

Debbie: I can imagine how troublesome quartz is to work with because of its inclination to fracture. You must have a lot of patience to work one stone for a whole day.

It is unfortunate that you cannot photograph the change in colour. May I ask, how big are the gemstones you are working with?When you say that the colour changes, do you mean for the whole of the gemstone, for part of it or is it like the fire of a brilliant cut diamond or an opal where it flashes out coloured light when moved around? 

Birefringence of anisotropic material, retardation of light through a double prism, Zeiss colour chart of interference from polarised light, are all areas to explore. Is it possible that the faceting of the quartz is causing polarisation of the light passing through, leading to interference and hence colour changes in the gemstone?

Newbie

 

 

[Debbie K]

Newbie:

I'm not a terribly patient person, that's why I don't have more specimens. The stones are 2-6 carats in size and their diameters range from 8-13 mm. When the color change occurs, the entire stone changes. On a separate note, I was able to achieve some rather exceptional dispersion with the cut, especially around the edges. The center area of the stones where the tables are don't have as much fire; visualize a donut as the hole being the table and you can understand what I'm talking about. The point of doing this different cut was to shift the reflected prismatic spectrum to the blue, more like a cz or a diamond.

I will try to explore the possibilities that you've listed, but I'm really out of my depth with a lot of this stuff. I don't think the birefringence has a lot of an effect as quartz is pretty low, but it may be a factor. I've been looking at linear and non-linear optics just trying to understand what might be happening, but I don't have the background to understand the math.

The reason why I posed this question here is it happens in outside sunlight. Nothing else I've tried results in these changes. It's truly bizarre behavior for a piece of quartz and I will continue to try to photograph the colors (maybe borrow a better camera). The range of colors and the fluctuation between them, the mechanism that is causing the effects and my inability to reproduce those conditions are the things I am struggling to understand.

[HalfFeralHuman]

If the piezoelectric effect is behind what's going on here, it'd require an extremely specific frequency set up a stable resonance. Without this, the effect wouldn't last long enough to be visible. While background EMF may play a role here, it'd only be if that noise was at this specific frequency. The crystal itself would serve as an extremely efficient noise filter.

Ionosphere height may change the profile of background EMF, and that'd fit with the kind of timings Debbie is describing.

With all this said, it still seems like one hell of a long-shot.

 

I'm thinking light polarisation is a much more likely candidate. I'm wondering if you've (@Debbie K) got a strong polarising filter, or pair of 3D movie glasses. You could test the response to light polarity with that.

@Debbie K, About photographing it:

Is your camera able to save images in raw format? You may be able to capture something from that if it can - raw format stores camera data as it comes without any kind of colour correction or processing.

You might be able to get something by photographing the crystal with a white sheet of paper (using the same type of paper each time). You'd then want to get the average of each of the R, G and B channels, and compare those to the total average average value. That'd give you 3 ratios of R,G,B:Total. You'd need to do this on two cropped portions of each image, one of the white paper to get the background light colour, and one of the coloured section of the crystal to get it's colour. In the comparisons you may find some actual data. It'd be inaccurate, but you might get something. You should be able to do this with something like GIMP (an open-source alternative to Photoshop).

Personally I've found my own camera able to pick every visible frequency pretty well (ie. photographing art doesn't end up with distorted colours), but I suppose it all depends on the sensor.

[constellationscockta]

Im also in Houston, Texas. I have cameras and filters that can record in narrowband, UV and infrared (as many astrophotographers do). I'd be happy to document this, as I'm also a solar astroimager

[Debbie K]

HalfFeralHuman:

The more I look at it, the more I think it has to do some kind of atmospheric polarization phenomenon. On cloudy or overcast days, the predominant colors are yellow to green. On sunny days, yellow to pink to purple.

If it is, would it have any practical application for anything?

I don't think any of my phones or my old Canon camera has anything sophisticated enough to do what you are recommending. The Canon might, I need to find its manual to see if I can make these kind of adjustments. I found nothing on the menu of the camera that looked anything like what you are saying.

constellationscockta:

I really might take you up on that. I'd hate to ask it of you, as it takes patience to wait for things to start happening; maybe we should wait until it's a little cooler here. I'm in southwest Houston; where are you?

I tried again today to get pictures (not a good day here for me, overcast and cloudy) and the only colors I could see were a very subtle yellow to greenish. I pulled out my old Canon camera, and it, too, converted everything to white. Interestingly enough, my husband's Alcatel phone, while it can't focus on the stone, seems to pick up some of the color.

I hesitate to post these, as they are incredibly crappy pictures, and the changes are very subtle, but maybe you can see the color differentiation. Same stone, just different times withing a 15 minute span of time. This was a bad day to try to show this, the colors are usually much more dynamic. This stone honestly is a clear quartz with no body color.