I've done quite a bit of it. Western Wyoming is full of fluorescing material. Quite a bit here in Idaho, also. I use a dual bulb unit. Each bulb is 18 watts...really a strong light. It's also heavy, and I carry it on a handle, like a metal detector. I use a sling around my shoulders to support the weight. One bulb is shortwave light, and one is longwave light. Some material fluoresces under one, but not the other. Some material fluoresces under both, but different colors under each wavelength. This type of light is expensive, and uses lots of power. An 8 pack supply of 'D' cell Nicads lasts about 1 1/2 hours if both bulbs are on all the time.
You can get by much easier by getting an LED UV flashlight, but they don't make a shortwave LED light, so you'll miss some material. The good news is that most gems that fluoresce do so under longwave light. :-) Not all gems fluoresce, however.
If you do this, you should also buy a set of UV protective goggles. Your eyes don't focus well under UV light, and that causes a certain amount of nausea. The goggles really lessen that problem. They don't cost much, either. If you use SW light you REALLY want the goggles. If the SW light reflects off the surface of glass, or maybe water, it can damage your vision permanently. You should NEVER look directly at the light source of SW UV light.
Jim
here
