Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Jan 18, 2008 1:07:37 GMT -5
Has anyone tried a long wave UV LED flashlight? I thought I might get one and try finding some fluorescent rocks if they are any good. I see you can get them for about $20 on Ebay. Is there anything in particular I should look for before I buy?
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AgateHeaven
starting to spend too much on rocks
Member since September 2007
Posts: 197
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Post by AgateHeaven on Jan 18, 2008 1:35:52 GMT -5
Scott W, Let me know if it works...that would be cool to have at the WWR outing. Lots of fluorescent calcite there. AgateHeaven
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rallyrocks
fully equipped rock polisher
Member since November 2005
Posts: 1,507
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Post by rallyrocks on Jan 18, 2008 14:42:52 GMT -5
UV radiation comes in two main varieties, Long wave (LW) is cheaper, safer, and is commonly deployed in discos, bowling alleys and psychedelic shops. It will light up a few select minerals, but not all that are considered "florescent".
Short wave (SW) is more expensive, long term exposure is dangerous to skin and eyes, but SW tends to "light up" a lot more different minerals than LW does.
I'd have to imagine these LED lights are LW, oops, I just noticed you mentioning that, so yeah- still it sounds like a good price and they will help illuminate and/or identify some stuff
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KG1960
has rocks in the head
Member since August 2008
Posts: 512
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Post by KG1960 on Jan 19, 2008 17:45:02 GMT -5
This question intrigued me. I did some Internet searching and found, along with some others, the following link. I have never heard of this company, so I can't say if they are good guys or not, but it will give you an idea of what is available. These are all long wave UV LEDS. One or two web sites said that short wave UV LEDS do not exist yet. As been said, the long wave will fluoresce some rocks but other rocks need short wave UV. BTW, one web site advertised you can use their UV light to detect urine, semen, and blood stains on hotel beds. Now that's a comforting thought. Here's the link: store.advancedmart.com/uvuledfl.html
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Jan 20, 2008 22:52:05 GMT -5
I did some more looking into it and found out that the ideal long UV wavelength is about 360-365nm for rocks. Most of the LED's are 380-390 nm they do make them at 360 but big bucks. I just ordered a small handheld fluorescent tube light on Eba. It seems that florescent ones produce about 362nm from what I read. Not as much battery life but I can afford one of these.
Thanks for the info, I will put on some pics if I find anything interesting.
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Post by catmandewe on Jan 20, 2008 23:28:49 GMT -5
I have one of those handheld tube lights, works OK, not fantastic, but at the price it is good enough. I have not had to change batteries yet and I have had mine for quite a while now.
Tony
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DeanW
has rocks in the head
Member since December 2007
Posts: 721
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Post by DeanW on Jan 22, 2008 15:06:57 GMT -5
I have both a small dual-mode (1/2 LW, 1/2 SW) handheld unit and an LED LW "pocket flashlight". Turns out that a lot less is LW stimulated than I had hoped, but the flashlight is pretty small and was only $12 at a local rock show.
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Post by LCARS on Jan 22, 2008 22:58:16 GMT -5
Hey Scott, as fact has it I have actually modified a white LED flashlight to use 4x 375-380nm LEDS instead. (camera's color filters cause the glow to appear indigo blue but it is actually a deep hazy violet to the eye.) If you are looking for advice on using them for looking for flourescent materials you need not look any further. I had to do research on fluorescence for a work project back in my R&D days. I am actually in the process of building a little project right now myself, a 12x UV LED spotlight to use for this same and "other" purposes as you will see it can prove itself useful in other ways once you start messing with it if it's not working out for finding rocks... You know, depending on how handy you are with manipulating small parts and soldering, you could technically build or modify something to suit your needs and if you know the right things, you can do it for cheaper than you'd expect. (ie where to get bulk Chinese imported UVA LED's that come with free batteries and happen to be available at a local Dollar Store.) Beyond that, you also need to know a bit about basic electronics and the typical characteristics of those particular LED's in order to get them running in their "sweet zone". The flashlight in the pic above runs on a 3.6v Lithium cell. The peak emission range for UV LED's is usually somewhere between 3.6-4.2v so 2 alkaline AA's just won't cut it but 3 AA's would require you to use current limitting to regulate power or the LED's might burn out under continuous duty with new batteries at 4.5v. If you want to stick with buying something prefab, you can expect to pay more than $50 for something that will actually suit your needs. Don't fall for any of the hyped up BS descriptions you read on Eburn about products featuring the longwave UV LED technology. They have become commonplace enough now that you should start to find some healthy competition for products featuring them. For any kind of joy using this technology for night hunting of fluoro minerals etc., I would personally recommend using something along the lines of a recharegeable spotlight utilizing at least 10 UV LED's (375-380nm) driven by a continuous duty alternating soft pulse-width modulated overdrive to provide you with the maximum possible emission and bandwidth these LED's can produce without burning them out, but hey that's just me.
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Jan 28, 2008 14:14:27 GMT -5
Well I just got my handheld fluorescent ;D. I've been checking all my rocks and about 5% of them glow. ;D Now I'm hooked, I just ordered a bigger one for in my display case. I even salvaged a few rocks out of my throw away pile out back, they didn't look to good under regular light but are much nicer under UV. Thanks for the help.
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Post by LCARS on Jan 28, 2008 22:13:15 GMT -5
Also, you may want to keep in mind that despite the fact the flourescent tube lamp units usually give a better reaction, they do not usually project very well unless you start getting up into the 25W+ units with parabolic reflectors. The working distance can be three feet or less wityh battery operated "portable" black lights which may lead you to skip over something fluorescent covered in some dirt where a close pass or more intense beam may have revealed that glow just beneath. Just a thought anyways, there is always some sort of trade-off when using something cheaper or more readilly available that might not be designed to work for your needs but as long as what you have works for you then you're good to go! Don't forget to post some pics of your hunts/finds.
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