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Long Wave UV vs Short Wave UV

I was just starting out on gemology, do I really need a short wave UV (254nm) alternative to a long wave UV (365nm)
Coz a short and long wave UV light cost around $190 and a long wave cost only $30. I’m on a tight budget, do I need to spend another $160 for the long and short wave version?

You comment is much appreciated.

If you are on a tight budget, look at the UV lights that claim antibacterial properties. All of these (barring fraudulent advertising) are short wave. They may not be the precise BEST frequency but they operate in the prescribed ranges. I got BOTH for less than $30 combined. Build your own box. Needed: Cardboard box of appropriate size (your choice), a knife to cut access holes and FLAT Black spray paint.

Buy gemologist quality tools when you have money. You can “make do” quite nicely with less for now…



Is there a major difference between UV 365nm and 395nm?
Or its both consider Long wave?

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Save up for a good light box. I’m in asia and is very reliable and there are many companies that make professional gemological tools. Fable is a very good company and its products are rebranded by many other companies.

An affordable UV light box is this one:

Here is a good article about using UV light… I read a couple of articles from GIA and Gem-A but I can’t find them. I did book mark this one since it has collected information from many sources and put them into a reasonably understandable format. However, it does need to be updated with new information about some new synthetics coming out of china.

Here is an article from Gem-A explaining how to use UV for analysis

Focus on Gemstone Fluorescence: Looking for the Light

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I bought a gemetrix jewellery inspector last year and cannot say how much it has paid back its cost! It has been invaluable in spotting lab-grown / synthetic stones and is a brilliant piece of kit.
Obviously if you are on a budget then I would say rather than spending smaller amounts on reasonable products sometimes its worth saving up and getting the right product for the right job. But it is up to you!
All the best!

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I built a a very compact, battery battery-powered shortwave UV (254 nm) for about $30.

I used a hiker’s battery-powered water sterilizer and a piece of ZWB3 filter glass

and just built them into an old plastic bottle.

You can easily build an SW UV (254 nm) unit. At the end of the day, they are all just a UV source, a filter (to eliminate the extraneous blue light produced) and a “box” to contain everything, ALTHOUGH I RECOMMEND ADDING A BARE ALUMINUM REFLECTOR (ANY PAINT OR COATING WILL JUST ABSORB SW UV, DEFEATING THE WHOLE PURPOSE OF THE REFLECTOR) : YOU CAN ALMOST DOUBLE THE USABLE OUTPUT WITH JUST THIS SIMPLE ADDITION.

The ZWB3 filter glass will be you most expensive part, and it will absorb about 50% of the output of a typical mercury-vapor 254 nm source, but it absorbs almost all of the contaminating visible light emitted, and makes the lamp much more useful

If you like to build things, this can be a CHEAP way to go.

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There is enough of a difference, and true 365 nm UV is cheap and easy enough to get, that for general gemology, it’s probably better to not bother with 395 nm, unless you have a specific purpose for 395 nm.

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Thanks for the idea.

I was lucky enough to get a 5 way torch from, with both short and longwave UV. I think there are 6 way rechargeable torches now, with 365nm and 395nm. Mains sterilizing lamps cover shortwave uv.

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@Cal59 If possible, could you please send me the link of where you brought the 5 way flashlight?

Sorry but the link for my torch doesn’t work now. I did have quick look at Ali Express and found many 6 way torches and also some UVC lamps/torches that can be as low as 254nm. Look carefully to avoid those with added UVA or blue LEDs. I spotted a couple at around 9$ +shipping and the 6way torches are around 30$.

I should have added that 395nm torches can be bought for under $15

Thanks for the input.