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Post by fas05l on Dec 15, 2009 9:55:08 GMT 10
hey guys,
just wondering if and where i can get a blacklight as a torch? i have looked in some electrial wholesalers and jaycar ect but no luck.
cheers brendon
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Deleted
Deleted Member
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Post by Deleted on Dec 22, 2009 23:10:09 GMT 10
ebay i bought some neons black light and turned them into a wand for gemstone detecting, they also do led and torches
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Post by Flying Scott on Mar 2, 2013 22:28:55 GMT 10
A black light wont do any good without a filter.
the filter ( depending on its colour ) determins what mineral you will see useing the black light.
It took me a couple of years to get it right.
A florecent black light is way out of the spectrum of human sight, I can pick up reflections from dandruf and other florecent materials but would not detect a solid object like Sapphire, Quartz, Gold.
However! by using the filters you would see some. The filters come in various colours, therfor you need diferent colour filter for diferent colour minerals
Flying Scott
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Post by sapphireminer on Mar 12, 2013 16:03:50 GMT 10
Hi all Did a search on ebay and I bought 4 from China for less than $6 they run on 3 AAA batteries take about 3 weeks to get here Regards Dave
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Post by goldierocks on Dec 6, 2016 8:04:36 GMT 10
FYI - a black light is pretty much useless and that includes virtually all LED torch designs - only covers 5% of the UV spectrum (a couple of minerals will occassionally fluoresce with it - eg some ruby and calcite)- also lack filters (that are required to filter out visible light). If you want something that works, you will need to pay $100-$200 and get safety goggles for UV as well. This is the cheapest at present that has the minimum requirement for use with all fluorescent minerals: www.ultraviolet-tools.com/ultavi … -lamp.html This one is $US62 including postage from the USA and a pair of their UV safety glasses (has the disadvantage though that you must separately clip in and out the two different wavelength UV tubes) These two are twice the price but also adequate and local, and so far as I know there is no swapping UV tubes required: www.scientrific.com.au/product.php?p=1819www.prospectors.com.au/p-10799-u … -lamp.aspx All three of the above are low power (4W) so can only be used in the pitch dark or shining a few cm from the soecimen (so no good for walking up creeks at night unless you walk with your head on the ground). If you want something more powerful you will need to pay more in the range of $A450 (eg from prospectors). Do not use ANY of these above without UV goggles, which I have included in the price of the first example but not in the price of the other two (not expensive - $20 - $35). Must be designed to filter sw UV (the standard here is called AS/NZS 1338.2). sw UV will burn your eyeballs and it is best to use gloves as it can burn your skin - it is much stronger than in sunlight. I'm inclined to use gloves and goggles even with lw UV. These lamps cover both sw and lw (most lamps sold are lw only and only cover about 20% of fluorescent minerals, perhaps 50% of gems) I am a geo who uses UV |
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Post by shivan on Dec 6, 2016 10:12:10 GMT 10
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Post by goldierocks on Dec 6, 2016 10:56:52 GMT 10
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Post by goldierocks on Dec 6, 2016 11:34:05 GMT 10
www.prospectors.com.au/p-10799-uvp-mini-4-watt-uv-lamp.aspx is the third one - it takes you directly to the cheap but satisfactory lamp which is at the top of the page you mention which shows them all the portables. I posted a lot more info on prospecting australia forum where I also am registered, then thought I would share here, especially re current lamp info Things I posted there include which gems fluoresce under which wavelength, why things fluoresce, dangers of sw UV etc etc. Black light torches are next to useless, almost anything UV LED is useless, anything without a filter (eg most) is next to useless because they also emit visible light so weaken the fluorescence. One reason many people think they are OK is they get them for things like rubies, which have ununsual properties that often let them flouresce with a torch light - but other minerals mostly don't using the torch lights*. These three are fine under very dark conditions with the lamp next to the sample - virtually any mineral will fluoresce and they are good starter lamps. Personally I think changing tubes is a pain and would pay the extra $100 for one of the two local ones that don't require it (2nd and 3rd). If you want to search at night in the open on dumps, along streams etc, you are just going to have to pay the $450 or so for something really professional - moonlight interferes hugely. Also they are more powerful - the three 4W ones are the minimum power useful - 9W or more is much better (they simply throw out more power to the specimen so the specimen fluoresces more strongly - which helps counteract any visible light but also lets you stand up straight and walk while it is shining on the ground - with 4W you have to bend over and hold it only centimetres from the specimen- and they also give a much broader spread of the beam. We geos use them routinely in precious opal, tungsten and uranium prospecting and you soon learn that you get a bad back bending over so far (and you need the spread of beam, otherwise you are constantly having to move it back and forward over tiny areas). However the safety glasses are even more important with these - and NEVER look directly into the beam of any UV lamp of any wavelength, not even a torch and not even with safety glasses on (and note that they are special UV safety glasses designed to cut most UV). It is why Victoria has banned tanning clinics. Torch lights are designed for fingernail work, curing glue and checking who has been doing what in the hotel beds that the hotel hasn't changed for the next customer (it can be an eye-opener). Hope that helps. * for anyone technical - the reason with rubies is that all fluorescent minerals need to be "activated" by a certain wavelength of light that is in the sw or lw UV range - they absorb the light energy, it activates the atoms in the sample and the electrons in the sample jump into another eneregy level (another electron shell) and in doing so emit visible light, the colour depending on the wavelength of visible light emitted. With rubies, some can actually be activated not only by lw UV but by visible light extending as far as green. SHining an ordinary torch on the ruby still doesn't work, because all the other visible wavelengths enitted by a normal torch swamp any fluorescence fcoming from the sample. But the crumby $6 0r $20 torch UV lights emit the 5% of the UV light that is closest to the visible range (and only a tiny bit of visible light). So although useless for most purposes, they cut out enough visible light and include enough of the relevant UV range for ruby to cause it to fluoresce visbly - and the chromium in ruby that causes many of them to fluoresce is a aprticularly strong emitter. But be warned, the torches still won't cause some rubies to flouresce, and almost no sapphires,
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nuggethill
God of the Goldfields
A 4 1/2 oz find at Kingower by a friend
Posts: 519 
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Post by nuggethill on Dec 6, 2016 11:48:27 GMT 10
Thanks for all that information as it's very handy to know did sapphireminer ever come back to tell us how the Chinese uv lamps worked cheers Harry |
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Post by shivan on Dec 6, 2016 13:27:30 GMT 10
I tried to cheat and brought a cheap 20W UV bulb from bunnings. None of my dugway geodes fluoresced under it and only 2 bits of fluorite showed hints at fluorescence.
Will get a decent lamp and see the difference.
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