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20 hours ago, Hibby said:

2 questions:

 

is shortwave light the the same as black light?

 

is conglomerate the same as 'pudding rock'?

Hi Hibby... we'll ignore your second question because it has been suitably addressed above. Shortwave light is not the same thing as black light at all.

Light below the wavelength of violet light is described as ultraviolet light. Keep in mind as you read this explanation that ultraviolet (UV) light is invisible to the human eye. Longwave UV peaks at about 360 nanometers, while shortwave UV peaks at about 254 nanometers. Midwave UV light is generally considered to peak at about 312 nanometers. 

"Blacklights" are an inexpensive way for beginners to get started in the hobby as they do produce longwave UV light that will work fine for minerals that happen to fluoresce brightly when exposed to such light. While equipped with a visible light filter, these inexpensive filters are not nearly as effective as the visible light filters incorporated into shortwave, midwave, and longwave UV lamps suitable for observing fluorescent minerals. Hence the visible light inherent to using blacklights can and does frequently overwhelm the longwave UV light effects on fluorescent minerals.

Next basic thing to understand is that most minerals do not fluoresce brightly under longwave UV light. In order to see all the bright colors that make fluorescent minerals so attractive, as a minimum you will require a shortwave UV lamp. As a general rule of thumb, these are considerably more expensive than longwave UV lamps, and also should be used with protective eyewear.  A good battery-powered shortwave UV field lamp is priced comparably with entry level VLF metal detectors. Midwave lamps are usually purchased only by advanced hobbyists, and are at least as expensive as shortwave UV lamps. There are a number of minerals that respond better to midwave UV light than to either shortwave or longwave UV light. Hope this helps to clarify things a bit…

Jim.
 

 

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Jim - thanks for such a thorough answer. You even answered questions I hadn't answered yet (but was going to).

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Another Q - Do all ammonite fluoresce? I have a giant museum quality specimen and I am curious if it would glow like that.

IMG_2151.JPG

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2 hours ago, Hibby said:

Another Q - Do all ammonite fluoresce? I have a giant museum quality specimen and I am curious if it would glow like that.

IMG_2151.JPG

Hi Hibby… I can’t speak to this topic from direct experience, but I did take a moment (while viewing the Pittsburgh Penguins hockey game) to look on the Internet for an answer to your question. I was curious to learn more too.

According to The Fossil Forum, ammonite fluorescence will vary with the type of mineral replacement that has formed the fossil. That makes perfect sense, hence some ammonites will simply not fluoresce, some will fluoresce only under short wave UV light, and some only under longwave UV light.

Of course it goes without saying that the light intensity makes a difference as to how well potentially fluorescent minerals respond to UV light. Hope that helps...

Jim.
 

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One interesting thing to note about mineral replacement in some ammonites I have seen (and petrified wood too), if the conditions are right, the replacement mineral is cryptocrystaline quartz with opalescence.  Essentially you get a similar effect to fluorescence, but without the need for any wavelength of uv light.  It is like an enourmous fossil that is also an opal.  It wouldn't surprise me if the uv effect adds to the brilliance, though I know nothing about that.

Nice specimen Hibby.

 

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20 hours ago, Jim Hemmingway said:

Hi Hibby... we'll ignore your second question because it has been suitably addressed above. Shortwave light is not the same thing as black light at all.

Light below the wavelength of violet light is described as ultraviolet light. Keep in mind as you read this explanation that ultraviolet (UV) light is invisible to the human eye. Longwave UV peaks at about 360 nanometers, while shortwave UV peaks at about 254 nanometers. Midwave UV light is generally considered to peak at about 312 nanometers. 

"Blacklights" are an inexpensive way for beginners to get started in the hobby as they do produce longwave UV light that will work fine for minerals that happen to fluoresce brightly when exposed to such light. While equipped with a visible light filter, these inexpensive filters are not nearly as effective as the visible light filters incorporated into shortwave, midwave, and longwave UV lamps suitable for observing fluorescent minerals. Hence the visible light inherent to using blacklights can and does frequently overwhelm the longwave UV light effects on fluorescent minerals.

Next basic thing to understand is that most minerals do not fluoresce brightly under longwave UV light. In order to see all the bright colors that make fluorescent minerals so attractive, as a minimum you will require a shortwave UV lamp. As a general rule of thumb, these are considerably more expensive than longwave UV lamps, and also should be used with protective eyewear.  A good battery-powered shortwave UV field lamp is priced comparably with entry level VLF metal detectors. Midwave lamps are usually purchased only by advanced hobbyists, and are at least as expensive as shortwave UV lamps. There are a number of minerals that respond better to midwave UV light than to either shortwave or longwave UV light. Hope this helps to clarify things a bit…

Jim.
 

 

Thanks for your help Jim. Yes, my 60 watt short wave cost me $750 several years ago

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Hibby, look like nice Madagascar fossils,  good chance that the light materials on your fossils will fluoresce if they are polished. If they have been sprayed with clear they will not. I don’t know what the host rock is but looks man made 

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