Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic Time
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral Quiz
Photo SearchPhoto GalleriesSearch by ColorNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography
โณDiscussions
๐ฌ Home๐ Search๐ LatestGroups
EducationOpen discussion area.Fakes & FraudsOpen discussion area.Field CollectingOpen discussion area.FossilsOpen discussion area.Gems and GemologyOpen discussion area.GeneralOpen discussion area.How to ContributeOpen discussion area.Identity HelpOpen discussion area.Improving Mindat.orgOpen discussion area.LocalitiesOpen discussion area.Lost and Stolen SpecimensOpen discussion area.MarketplaceOpen discussion area.MeteoritesOpen discussion area.Mindat ProductsOpen discussion area.Mineral ExchangesOpen discussion area.Mineral PhotographyOpen discussion area.Mineral ShowsOpen discussion area.Mineralogical ClassificationOpen discussion area.Mineralogy CourseOpen discussion area.MineralsOpen discussion area.Minerals and MuseumsOpen discussion area.PhotosOpen discussion area.Techniques for CollectorsOpen discussion area.The Rock H. Currier Digital LibraryOpen discussion area.UV MineralsOpen discussion area.Recent Images in Discussions
GeneralTriboluminescence
2nd Dec 2010 13:08 UTCDavid Bernstein Expert
I was breaking up Quartz yesterday. The Quartz was heavily stained but the only mineral of note I found after breaking apart twenty pieces was Galena. I had been looking for Bismuth which was a possibility given the mine I collected the specimens from. While breaking apart one large piece, a large spark shot up, sort of like what you see when a match head explodes into flame. I then detected a smell of rotten egg, something I'm familiar with since my old elementary school constantly had that smell.
Is what I experienced, the spark that is, triboluminescence? And is the smell related to certain sulfides that may be present in the Quartz? Many thanks.
2nd Dec 2010 13:12 UTCAlfredo Petrov Manager
2nd Dec 2010 16:08 UTCDavid Bernstein Expert
2nd Dec 2010 16:27 UTCRob Woodside ๐ Manager
2nd Dec 2010 16:34 UTCAlfredo Petrov Manager
2nd Dec 2010 17:05 UTCRob Woodside ๐ Manager
2nd Dec 2010 17:50 UTCDonald Lapham ๐
Can't pressure on quartz generate a piezoelectric static discharge and this discharge generates Ozone. I seem to remember detecting the faint smell of Ozone while demonstrating triboluminescence using my Brazilian river tumbled quartz crystals.
2nd Dec 2010 18:09 UTCRob Woodside ๐ Manager
2nd Dec 2010 18:15 UTCAlfredo Petrov Manager
2nd Dec 2010 18:23 UTCRob Woodside ๐ Manager
2nd Dec 2010 19:16 UTCHenry Barwood
Wouldn't 3 volts per millimeter be 3 KV/meter, not MV?
Triboluminesce is very common in quartz. I have found over the years that high pressure quartz, such as rose and blue quartz from plutonic pegmatite cores, is often highly triboluminescent. The phenomenon is poorly understood.
2nd Dec 2010 19:22 UTCDavid Bernstein Expert
2nd Dec 2010 19:35 UTCAlfredo Petrov Manager
2nd Dec 2010 19:36 UTCRob Woodside ๐ Manager
I think almost all friction and abrasion is poorly understood. Recently it was found that "mountainous" asperities on abraiding surfaces got caught and released in a stick /slip action setting the "mountain" into vibration which broadcast phonons into the main xl. In this way the "friction" heated the xl. That's a lovely mechanistic view, but I'm not sure that's why my hands warm up when I rub them together.
2nd Dec 2010 19:48 UTCRob Woodside ๐ Manager
4th Dec 2010 06:29 UTCRay Hill Expert
4th Dec 2010 19:16 UTCAdam Kelly
but my understanding of some of these factors is rather elementry.
5th Dec 2010 04:13 UTCBill Lechner Expert
Bill
5th Dec 2010 12:05 UTCPeter Andresen Expert
5th Dec 2010 17:22 UTCHenry Barwood
I'm only familiar with quartz and fluorite. Has anyone done spectroscopy on these various triboluminescent minerals? If the effect were coming from electrostatic or piezoelectric forces, you would expect the UV/blue end of the spectrum to dominate, not red.
5th Dec 2010 19:15 UTCRock Currier Expert
5th Dec 2010 19:55 UTCRob Woodside ๐ Manager
Right now "pyroelectric" is listed for Weloganite under electrical properties. Both Pyroelectricity and Piezoelctricity requires an xl without an inversion centre, so you won't see that in Fluorite, but could well occur in Weloganite or leucophanite.
5th Dec 2010 20:30 UTCJames Christopher
5th Dec 2010 22:57 UTCDean Lagerwall Expert
-Dean
6th Dec 2010 06:16 UTCHenrik Friis
interesting with leucophanite. I am just wondering how to distinguish between triboluminescence and thermoluminescence in a case where you scratch a sample. I know leucophanite can have a very strong TL response (overloaded a detector at Daresbury), but I don't know how much heat is generated when a sample is scratched. Just thought that the described observations here may have a series of origins.
cheers
Henrik
6th Dec 2010 17:09 UTCRob Woodside ๐ Manager
6th Dec 2010 22:37 UTCRonald J. Pellar Expert
Piezioelectricity is a voltage induced by stress and is specific to crystal directions. Sufficient stress can cause a voltage high enough to cause a spark.
Triboluminescence is the release of light due to pressure. I remember a camping trip to Mt. Palermo where after dark we threw chunks of quartzite against a wall and watched the resulting flashes. Lots of fun!
There may be a relationship between the pressure and stress but not likely. The piezioelectric effect can be generated by a slow prolonged stress whereas the triboluminescence cannot be generated with slow application of pressure. It usually requires a rapid application of pressure.
The sparks were generated by the same principle that a flintlock rifle ignites the gun powder, i.e., quartz against iron or steel generating a hot spark.
7th Dec 2010 04:51 UTCRob Woodside ๐ Manager
I think triboluminescence has to do with light being emitted on fracturing, so that symmetry is irrelevant. I don't know of anything that glows when a constant or variable pressure is applied.
I think the relation between pressure and stress is well summarized in the stress tensor. The stresses are the "off diagonal" terms in a matrix representation of the stress tensor. Since the stress tensor is symmetric, it can be diagonalized with an appropriate coordinate transformation and the diagonal values are the pressures or the principle stresses. In an ideal fluid, the three are equal and this is the number that is given for atmospheric pressure in weather forecasts. If rocks were ideal fluids, the pressure due to the weight above (lithostatic pressure) would be the same in the horizontal directions.
Thanks to Alfredo we understand the necessity of the strike plate in flintlocks.
7th Dec 2010 12:04 UTCPeter Andresen Expert
As Rob mentioned, I have never heard of any minerals lighetening up by preassure alone - that vould be pretty easy to observe (and if occuring - miners vould sometimes not need to bring a torch?!;)). I had my larger trimmer inside a dark cabinet, and once trimming down some quartz rich samples, I could observe flashes of light just as the quartz broke, not as sparks - more like an internal pinkish-red colour...
Peter
7th Dec 2010 16:38 UTCRob Woodside ๐ Manager
Are there any published triboluminescent spectra?
7th Dec 2010 18:25 UTCRoger Curry
triboluminescent crystals
Spectra :
Sugar triboluminescence spectrum
Regards,
Rog
7th Dec 2010 19:59 UTCRob Woodside ๐ Manager
Without a spectrum you can't say for sure, but the triboluminescent colour in the first link looks like a typical Europium UV fluorescence. Do triboluminscent quartz, sphalerite or fluorite fluoresce the same fluorescent colours under UV?
In the second link the triboluminescence emission of winter green has an extremely broad peak, much wider than the disulfide UV fluorescence peak in scapolite which Earl ascribed elsewhere as due to temperature. l wonder what the temperature dependence, if any, there is in triboluminescence? To get a molecular nitrogen spectrum matching the triboluminescence spectrum out of sucrose which contains no Nitrogen shows how complicated this stuff can be, Perhaps the sucrose triboluminescence results from x-rays produced in breaking sucrose, as in the Nature link (buried in the first link), hitting the molecular nitrogen in the surrounding air?
7th Dec 2010 20:21 UTCDavid Bernstein Expert
Many thanks for posting.
12th Dec 2010 02:58 UTCFranklin Roberts
I first noticed the striking pinkish-orange luminescence of milky pegmatite quartz while sliding down a quartz pile on my butt on a moonless night in November of 2004. Charlie Thompson and I were night collecting at the Badu Hill Pegmatite in Llano County, Texas with our UV lamps and scintillators. After sliding down the quartz, Charlie and I noticed hundreds of bright yellowish flashes of light directly beneath my backside and a lot of feeble flashes in my wake where the quartz cobbles were still settling after having been disturbed by my passage. A strong odor of garlic was also noticed during the phenomenon, leading me to suspect that something other than triboluminescence was at work here. Because of the highly specific conditions under which the glow was created, I dubbed the phenomenon "proctoluminescence" in my field notebook.
The milky white color of Llano Uplift quartz is due to trapped microscopic gas bubbles in clear massive quartz. Rubbing two pieces of this quartz together vigorously produces a pinkish-orange flickering light reminiscent of a distant thunderstorm on a warm summer night along with the same strong odor of garlic. I thought that the garlic odor had a familiar smell to it, but it was Charlie Thompson who keyed in on it. Charlie, who designs silicon microchips for a major chip manufacturer, immediately recognized the garlic odor as silane, (SiH4), a poisonous pyrophoric gas used in the fabrication of silicon integrated circuits. Silane reacts violently with atmospheric oxygen and humidity, catching fire instantly upon contact with air. Workers in wafer fabrication facilities are trained to recognize the aroma of garlic as a sign of a dangerous silane leak. Here in Austin, hardly a month goes by without AFD HAZMAT being called out to handle a silane leak at one of the major chip fabrication facilities here. More often than not, these leaks result in small fires as no ignition source is required. There are several industrial gases used in chip manufacture that are pyrophoric (self-igniting) and give off a garlic aroma. Germane (GeH4) and phosphine (PH3) are two that come to mind.
I suspect that the microscopic gas bubbles in the quartz are in fact silane, created when the still-fluid quartz catalytically reacted with superheated water during the later stages of pegmatite cooling. I have a pet hypothesis that rubbing two pieces of this quartz together in the dark ruptures gas bubbles near the surface, releasing trapped silane which then ignites in the air, generating flashes of light and the telltale garlic aroma.
I haven't researched this hypothesis, but it wouldn't be hard to test. Subjecting a thin slice of Llano milky quartz to microwave or RF excitation should cause any gas molecules trapped in the quartz to glow with characteristic spectral lines. Identification of the gas would be a simple matter of comparing those lines to those of known gases using a simple spectroscope. Crushing a sample of the quartz in a sealed container under hard vacuum would free up a tiny sample of the gas for further study.
Frank
12th Dec 2010 18:46 UTCAdam Kelly
12th Dec 2010 20:00 UTCRock Currier Expert
12th Dec 2010 20:38 UTCRob Woodside ๐ Manager
12th Dec 2010 23:49 UTCDean Allum Expert
I hope all that typing isn't wearing you out.
I think you are mentioning a type of triboluminescence that is unique to the milky quartz of the Llano uplift (it does sound like a powerful mechanism). You would probably agree that triboluminescence is more like thermoluminescence in other materials such as in the video that Roger posted.
I keep on thinking about something you wrote when you taught us about thermoluminescence. The underlying defect recombination produces photons with several electron volts of energy. These are in the UV spectrum. These higher energy photons are converted to light in fluorescent minerals (convert UV light to visible light) so that we can see that they are thermoluminescent.
There may be many more thermoluminescent materials that we do not know about since they are NOT also fluorescent. Perhaps we could detect that they are thermoluminescent by heating them adjacent to a phosphor, such as glass from a fluorescent light bulb. These potential UV thermoluminescent minerals need to be transparent in the UV spectrum. Of course exposure to gamma radiation is also a prerequisite for thermoluminescence.
The F centers which you mentioned have been well studied in the alkali-halides, so I wonder what are some good mineral candidates?
I have a non-fluorescent fluorite and a halite crystal which have been sitting under a uraninite crystal for 2-years in an attempt to get a color change (hasn't happened). Over the Christmas break, I will try the heating/phosphor experiment on these.
Best regards,
Dean Allum
13th Dec 2010 18:02 UTCRock Currier Expert
13th Dec 2010 23:17 UTCFranklin Roberts
One characteristic of the light emitted from the Llano quartz that distinguishes it from the other triboluminescent minerals I've encountered in the Uplift is the rapidity with which it extinguishes itself. The light emitted by the quartz would best be described as a flicker, having an extremely fast rise and decay. The triboluminescent fluorite and tremolite I've collected exhibit a time vs luminosity curve having a decay of several seconds after being struck or rubbed, almost like a phosphorescence decay curve. Fluorite from the Petrick Pegmatite will leave a fading lavender streak when rubbed on a chalk board. A tremolite outcrop in the Sunrise Beach area of Llano County will leave a blood-red luminescent spot when struck with a crack hammer in the dark. That glowing spot can sometimes take ten seconds to fade to black.
I'm not sure that you'll be able to generate enough color centers in your fluorite using uraninite as your gamma source, at least not in any useful time frame. I've read of it being done in a couple of days using cobalt 60 sources emitting hundreds of rads/hour of gamma. I'd be surprised if you registered more than a few millirem/hr with your natural gamma source. Would you like some thermoluminescent fluorite or Llano milky quartz to experiment with?
Frank
13th Dec 2010 23:54 UTCDean Allum Expert
Thanks. You already sent me a Petrick fluorite, so I will take a look at its' triboluminescence.
Rather than use a complicated scintillation setup, perhaps I will learn how to do a long exposure on my camera.
I know someone with access to CO-60, so please suggest some mineral types. The concept of a nuclear powered flashlight is appealing!
You've probably already seen the little ones from this fun company:
United Nuclear
-Dean Allum
14th Dec 2010 06:49 UTCFranklin Roberts
This phenomenon isn't limited to quartz. Microcline and pink granites containing microcline will become brilliantly fluorescent along blast fractures after a shot. Instead of the beautiful vermillion red shortwave fluorescence characteristic of microcline, the shocked material exhibits a brilliant bluish-white glow similar to that emitted by laundry detergent. Deep fractures not directly exposed to the explosion glow just as brightly as those nearest the shot, suggesting that contamination by the explosive or its reaction products is not the source of the fluorescence. Washing will not remove it either.
Any ideas?
Frank
14th Dec 2010 09:43 UTCNoah Horwitz
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are ยฉ OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 26, 2024 19:35:32
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are ยฉ OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 26, 2024 19:35:32