Would anyone know more about gem identification UV lights? I’ve seen some Nitecore portable flashlight-like models, but I imagine they use 365 mm LEDs and I don’t believe they use filters.
I also know that besides the 315-400 nm range, shorter wavelengths between 200-280 nm are also useful in identifying some stones and imperfections, but that wouldn’t be LEDs anymore?
Any pointers are appreciated.
Good question. 
I think some LEDs in this range do exist but they are very expensive.
Also this is straight-up cancer ray territory. Just saying. 
Well…that’s something of a buzzkill, isn’t it?
For the longer UV-A range, I suppose there is no reason not to use this light.
I was thinking about some smaller, specialised one, but take a look at this video: https://youtu.be/7DM74RCOidU?feature=shared
A UV light(s) is part of a toolkit, you’ll have to know what wavelength is best and what reaction you’re looking for for each individual stone.
Can’t recall if I’ve pointed you in the direction of fluomin.com website, example linked is fluorite which is one of the best examples of fluorescent minerals.
There are an abundance of 365nm lights (with filters) on the market.
Shorter wavelength LED lights do exist, they are expensive, Raymond-Wu is a supplier.
Other shortwave lamps use fluorescent tube technology which is older but can pump out more UV as the affordable LED options are quite low powered. My Superbright 3 from UVSystems visually appears to put out more SW UV than my shortwave LED light I got from Raymond-Wu, but, it’s a floody light whereas the LED is a spot. The difference in beam patterns means the Superbright 3 is better under prefect conditions (dim lighting, close up), whereas the LED light is better in less-than-perfect conditions, uneven or brighter daylight, rough ground/field use.
Yes SW UV is hazardous, use adequate protection, goggles at a bare minimum.
If you haven’t come up with a solution yet LMK. I can either point you to suppliers so you can DIY or I can assemble LW, MW and SW lights.