Fluorescent Fossils Under Uv Light

[Bev]

Hi Guys and Gals,

Does anyone know much about fossils that glow fluorescent under UV/blacklight? I was reading about minerals that do this and the article said that quartz, fluorite, calcite, amber, and agates do this (several more but not stuff we have around here I think.)

Well, I went out and bought a cheap UV flashlight and a blacklight bulb. The blacklight bulb didn't really do anything, but it does work because my white clothes look really white!

However, the flashlight was oh so cool on the recept cross sections! Some turned green and yellow under the light! My one agatized brach showed some fluorescence and so did some of the quartz - mostly in the yellow/greenish range. Others nothing and then I got some tiny spots of a light blue!

This was also mentioned as a way to night hunt minerals, which would probably work with fossils as well?

I also think this would make an awesome science project and/or Halloween Display!

Any ideas though why the blacklight bulb (a fluorescent bulb) doesn't work as well as the flashlight (LED)?

I'm going out tonight with the flashlight to look around at my fossils outside. Will keep you posted!

PS It is also supposed to work on certain bugs, master scorpions, and some flowers. And that certain insects do see the UV rays so they see the fluorescenct glow. And blood, urine, and other body fluids - CSI. LOL :-D

Edited September 29, 2013 by Bev

[Bev]

I just got in from outside searching with my little UV flashlight. WOW!

About half the cephs have some fluorescence. My first two trilobites, not out of the rock yet, are greenish yellow. Lots of yellow spots on things, some have a strong purple glow way beyond the lights purplish cast.

And I have one rock, that I don't believe is a fossil unless maybe a coral, that GLOWS bright yellow and purple!

Very, very cool!

Anyone have any explainations or how I should research this further?

Bev :-D

[Coco]

Hi,

Any ideas though why the blacklight bulb (a fluorescent bulb) doesn't work as well as the flashlight (LED)?

Probably because they aren't ont he same wavelenght (long "waves * " or short "waves") and thus they don't make react minerals in the same way (I think that it is minerals contained in your fossils which make them react in UV).

* I don't know the real word...

Coco

[paleoflor]

If the fossil is permineralised by some mineral which is fluorescent, then sometimes, so is the fossil. There are even examples where weak tissue is persevered as a fluorescent imprint (so becomes visible under UV light), if I am not mistaken.

[Auspex]

Good stuff here= LINK

[painshill]

Whether or not a fossil fluoresces in UV light depends on a number of factors. Most commonly it’s the replacement mineral for the fossil that fluoresces but many pigments in the animal and plant world (or their conversion products during fossilization) will also fluoresce. Fluorescent pigments are generally visible to insects, fish and birds. They’re one of the mechanisms by which flowering plants attract pollinating insects and help some animals to recognise predators or attract mates.

There are dozens of minerals which have this property but most usually they need an “activator” to be present. Sometimes there is a maximum level of the activator, beyond which there is no fluorescence, and often certain other impurities need to be absent (in both cases to prevent what is known as “quenching” which inhibits flouresence).

Although many types of calcite will fluoresce for example, the activator needed is divalent manganese in concentrations of a few percent as a maximum. Iron and copper are common interference impurities causing quenching. It’s a matter of chance, depending on locality, whether the right combination of minerals were present at the time or have arisen from secondary replacement subsequently. Sometimes, even two localities quite close together yielding the same fossils that appear to have the same kind of replacement may have quite different fluorescence properties with respect to colour or presence/absence of fluorescence.

Next, we have the spectrum to consider. Near ultra-violet is regarded as between 400-300 nm and far ultra-violet as between 200-122 nm (with mid-ultra-violet between them). So-called “black light” generally has a spectrum between 400-315 nm and may be characterised by an “emission peak” within that spectrum where the intensity is the highest. That’s achieved by filters or coating on the glass and generally, the more you pay for a light sources, the narrower and more intense the emission peak. Far ultra-violet sources are generally used for purposes such as bacterial sterilisation and not readily available to the general public.

So, when we talk about “far” and “near” UV in the context of “black light”, we generally mean the relative peak emissions within the 400-315 nm range. A mineral may fluoresce in the far end of the spectrum or the near end or both. If it fluoresces in both then it may exhibit the same colour or different colours. Mineral fluorescence is rather more common in the far end of the spectrum (the shorter wavelengths). Pigment fluorescence is most common in the 400-300nm range since that’s the area visible to animals with UV vision. The intensity may also vary in different parts of the spectrum. Even when there is no fluorescence as such, UV light can create an enhanced contrast between fossil and matrix such that features can be seen which were not otherwise apparent in the specimen.

Finally, we have the purity of the light source to consider. The main reason we can’t see the fluorescence exhibited by many of the materials around us is that sunlight is so strong in what we call “white light” that it overwhelms the fluorescent effect produced by the lower intensity of the UV within the overall spectrum. If you buy a cheap, unfiltered light source then the same applies. Cheap UV light sources will often also emit so much white light that they won’t allow fluorescence to be seen unless it is extremely strong. It’s possible to improve on that by using filters. The square filters sold by photographic shops under the “Cokin” brand can sometimes be helpful in blocking out parts of the spectrum that are interfering (particularly those that block visible blue light). Some UV lamps designed for mineralogical use may be “dual-source” in that they have a filter which enables you to switch between near and far ends of the spectrum.

You may find the attached pdf file interesting:

UV Fluorescence - Night Hunting for Small Vertebrate Fossils.pdf

Incidentally, some of the modern resins used for gluing and restoring fossils also fluoresce under UV light and this can sometimes be a useful way to determine the amount of restoration in purchased specimens.

Edited September 29, 2013 by painshill

[Bev]

Wow painshill! THANK YOU!

[Bev]

Good stuff here= LINK

That was a fascinating thread Auspex - THANK YOU! Who knew that they may also glow after you turn the lights on!

[Bev]

So, I was thinking that I might set up an aquarium just with the fossils that fluorese. And buy a better flashlight for some night hunting.

Thoughts on what I should be looking for in UV range? Sources for GOOD UV light sources?

[old dead things]

In Lance Grande's new book "The Lost World of Fossil Lake" he suggests using a UV light to find fossil feathers. As soon as I find the section again I will post the page number.

When I first started collecting fossil fish twenty some years ago, I remember one night in the dark garage checking the rocks for fluorescence and wondering if it would work on fish plates, no, no feathers, but I found it interesting that I read about the practice twenty years later, so now I will have to go check all my fish plates again.

Jim

Old Dead Things

[Auspex]

So, I was thinking that I might set up an aquarium just with the fossils that fluorese. And buy a better flashlight for some night hunting.

Thoughts on what I should be looking for in UV range? Sources for GOOD UV light sources?

Serious rockhounds use a lamp that is selectable for longwave, shortwave or split-tube longwave/shortwave combination. Good ones are expensive, though.

[old dead things]

The Eloxite Corporation in Wheatland, Wyoming www.eloxite.com offers a 4watt long/short for $88. I have one and it works great.

Jim

Old Dead Things

[painshill]

There are plenty of places that you can buy tubular UV light sources suitable for display purposes relatively inexpensively, and you can of course mount more than one type of tube above a display so that you get a wider spectrum of UV wavelengths and the best chance of a colourful result. This company has 4-Watt tubes which are around a foot in length in long, medium and short regions of the spectrum for 10-15 Dollars for example:

http://www.3rdplanetsamples.com/default.asp?page=UV_Light_Bulbs

But, I would be caution you about anything other than long-wave sources (UV-A tubes) and even then you need to be aware of the potential risks if you are considering long-term display rather than short-term observation. Even short-term direct observation of bright short-wave UV (ie UV-C tubes), can cause inflammation of the cornea and other serious eye conditions as well as being very bad for the skin. Eye protection is recommended for short-term exposure to both UV-C or UV-B and for long term exposure to UV-A.

A 4-Watt tube is not a bright source in the context of exposure risks and you will want to shield the tube(s) so the light goes onto the specimens, not out into the room. To put the risk in context, a typical home sun-bed would probably have a dozen or more tubes in excess of 100 Watts emitting principally UV-A wavelengths and a professional tanning salon might give you double that exposure with a small proportion of UV-B. Neither would give you any UV-C exposure.

[erose]

Bev,

We need to nominate you for Member of the Month if for no other reason than you inspire the best discussions. Painshill has done a great job of describing what is going on with fluorescence. And take his safety/caution advice seriously. You will not know your eyeballs are fried until it is too late. Main thing is to never look directly into the lamp and be cautious of using it around highly reflective surfaces.

I have a small collection of fluorescing fossils that started by my noticing that my Petoskey Stone was glowing during a college party. (FYI, tonic water glows blue like an atomic reactor's cooling pit!) From there I went on to discover a variety of fossils within my collection that glow. I never got heavily into collecting minerals other than a drawer full of fluorescing specimens. fascinating stuff for sure.

Two items for clarity:

Painshill uses the terms near and far for UV. Some folks will use the terms long and short. That refers to the wavelengths. So near is long and far is short. Some minerals, and I would even guess fossils, can emit in two different colors depending on the wavelength.

The light you see from the glowing fossils or minerals is not ultraviolet. The ultraviolet light is almost invisible to humans. What you are seeing is the light, in a visible wavelength, emitted by the reaction in the exposed atoms of the minerals.

You may also run into stuff that phosphoresces. That is when you turn off the lamp and it continues to glow for a period of time. If you ever see those big rhomboid fluorite specimens at rock shows ask if they phosphoresce. The effect is way cool and well worth the price.

I suspect some of the spots of color you are seeing may be organic impurities on the stone. I was confused on a few pieces until I washed them well and then the spots were gone. I think they were molds or fungi.

I have also run into one other odd effect. This is something the mineral collectors know better. Sometimes things lose their color, or fluorescence, after being unearthed and exposed to daylight. I had some Selenite crystals from upstate New York that died after a year. Right after digging them out of the clay they were in they glowed a wicked deep green under long/near wave but after a year...nothing. So far this has not happened with any of my fossils.

Take care,

Erich

Edited September 29, 2013 by erose

[Bev]

Thank you so much Erich! Lots to think about and research! :-D

[painshill]

I agree… Bev’s natural curiosity is an excellent stimulus for interesting discussion. Good info. As Erich says, it’s confusing that not everyone uses the same terminology (or even if they do, the words aren’t always used with the same meanings). The ISO Standard defines the terms in use as follows (taken from Wikipedia):

There’s another interesting property displayed by a few minerals when exposed to UV light – known as “tenebrescence”, which is a reversible effect. After UV exposure (strong sunlight can be enough) the mineral changes colour and then changes back again when removed from exposure. The effect can be repeated indefinitely but is destroyed by heating.

It’s the principle behind self-adjusting sunglasses, which darken on exposure to sunlight and also “girly” nail varnishes which change colour in the sun… but the materials used there are synthetic.

Some members of the sodalite family (such as hackmanite and tugtupite) exhibit it quite strongly. The colour change is normally from white/colourless to purple-red after exposure. Spodumene (a lithium-rich silicate) also exhibits the property, changing from white/colourless to green.

Another useless piece of information… small rodents such as rats and mice produce frequent trickles of urine and owls track them at night from the fluorescence in the urine trails they produce.

[donckey]

Bev and Painshill,

Thanks for the idea and information.

I knew that this method is used in Australia looking for precious opals.

I have to do some experiments now with some bonematerial.

Peter

[Ridgehiker]

I'm more familiar with fluorescent minerals than fossils.

But...a couple decades ago a large sauropod dubbed Seismosaurus from New Mexico was worked on in a lab. Some vertebrae were locked in hard matrix and it was difficult to distinguish bone from rock. They used fluorescent light of some type to distinguish bone from rock when chipping away.

.

[FossilDAWG]

Not a geological contribution, but scorpions fluoresce quite strongly. This works to their disadvantage when people use that to collect large numbers of them to stick in acrylic paperweights as a "Souvenir of Arizona". Blacklighting, shining a UV light on a white sheet, is also a good way to attract a lot of insects.

I use a UV light box (a "transilluminator") virtually daily to visualize and photograph DNA bands in agarose gels. Sometimes I want to recover the DNA, in which case I cut the glowing band out of the gel with a razor blade. The first time I ever did this I didn't realize that it is necessary to minimize exposure of the DNA to the UV, so I worked pretty slowly to cut out the bands without getting too much extra gel attached. It's a good thing I was wearing eye protection, because when I got home home my wife took one look at me and asked what the heck I had been doing. I didn't know what she was talking about, so she told me to go look in a mirror. Well I had a GREAT flaming red suntan all over my face, except for right around my eyes. I looked like some bizarre negative image of a raccoon.

So while it's true that UV lights are lots of fun, it's also true that you should minimize any direct exposure to your eyes especially.

Don

[Bev]

@ Northstar, I believe it is the minerals that fossilized that are glowing. What gave me the idea of shining a UV light on the fossils was reading about how minerals may be fluorescent.

[painshill]

There is a membership group known as the “Fluorescent Mineral Society”. Their website notes that out of 3,600 officially recognised minerals, more than 500 of them may exhibit fluorescence. In some cases that may be locality-dependent and it relates to whether or not an “activator” (mentioned in my earliest post) is present at the correct level:

http://uvminerals.org/fms/minerals

The website has links to members’ examples of fluorescent minerals and a database of localities where fluorescent minerals occur.

Scorpions (live ones!) do indeed glow, and one of the members has provided some example photographs:

http://uvminerals.org/gallery/v/members/uvgeologist/Glow+Show/

Here’s a nice exhibit from a museum display (not from that website) showing some of the possibilities (and several of these minerals are possible in replacement fossils or the surrounding matrix/infill):

[picture by Dr Hannes Grobe – Creative Commons license]

The numbers in the key relate to the following specimens:

1. Cerussite, Barite – Morocco

2. Scapolite – Canada

3. Hardystonite (blue), Calcite (red), Willemite (green) - New Jersey

4. Dolomite – Sweden

5. Adamite – Mexico

6. Scheelite - unknown locality

7. Agate – Utah

8. Tremolite - New York

9. Willemite - New Jersey

10. Dolomite – Sweden

11. Fluorite, Calcite – Switzerland

12. Calcite – Romania

13. Rhyolite - unknown locality

14. Dolomite – Sweden

15. Willemite (green), Calcite (red), Franklinite, Rhodonite - New Jersey

16. Eucryptite – Zimbabwe

17. Calcite – Germany

18. Calcite in a Septarian nodule – Utah

19. Fluorite – England

20. Calcite – Sweden

21. Calcite, Dolomite – Sardinia

22. Dripstones – Turkey

23. Scheelite - unknown locality

24. Aragonite – Sicily

25. Benitoite – California

26. Quartz Geode – Germany

27. Dolomite, Iron Ore – Sweden

28. Unknown

29. Synthetic Corundum

30. Powellite – India

31. Hyalite (opal) – Hungary

32. Vlasovite in Eudyalite – Canada

33. Spar Calcite – Mexico

34. Manganocalcite? – Sweden

35. Clinohydrite, Hardystonite, Willemite, Calcite - New Jersey

36. Calcite – Switzerland

37. Apatite, Diopside - United States

38. Dolostone – Sweden

39. Fluorite – England

40. Manganocalcite – Peru

41. Hemimorphite with Sphalerite in gange – Germany

42, 43, 44. Unknown

45. Dolomite – Sweden

46. Chalcedony - unknown locality

47 Willemite, Calcite - New Jersey.

[Bev]

Painshill, you are a wonderful, wonderful resource! THANK YOU SO MUCH!

Here is a company that sells a shortwave UV starter kit basically set up for a hobbiest or classroom for <$40

http://ultraviolet-tools.com/index.php

I just bought it, so we'll see how it works!

[Bev]

Here is an excellent article on inexpensive and some portable UV mineral displays:

http://users.ece.gatech.edu/~hamblen/uvminerals/Fluorescent_Mineral_Displays.htm

[siteseer]

Bev,

If you search this site for "ultraviolet" or "fluorescent," you will find some older threads related to this topic.

Jess

Hi Guys and Gals,

Does anyone know much about fossils that glow fluorescent under UV/blacklight? I was reading about minerals that do this and the article said that quartz, fluorite, calcite, amber, and agates do this (several more but not stuff we have around here I think.)

Well, I went out and bought a cheap UV flashlight and a blacklight bulb. The blacklight bulb didn't really do anything, but it does work because my white clothes look really white!

However, the flashlight was oh so cool on the recept cross sections! Some turned green and yellow under the light! My one agatized brach showed some fluorescence and so did some of the quartz - mostly in the yellow/greenish range. Others nothing and then I got some tiny spots of a light blue!

This was also mentioned as a way to night hunt minerals, which would probably work with fossils as well?

I also think this would make an awesome science project and/or Halloween Display!

Any ideas though why the blacklight bulb (a fluorescent bulb) doesn't work as well as the flashlight (LED)?

I'm going out tonight with the flashlight to look around at my fossils outside. Will keep you posted!

PS It is also supposed to work on certain bugs, master scorpions, and some flowers. And that certain insects do see the UV rays so they see the fluorescenct glow. And blood, urine, and other body fluids - CSI. LOL :-D

[Bev]

Thanks Jess! Will do! :-D