In the unlikely event you are ever in a public space and you see a blacklight display with glowing fluorescent colors, but the lights illuminating those colors are electric blue instead of deep purple, DO NOT LOOK AT THE TUBES, close your eyes immediately, turn around, shield your skin as much as possible, and get away from it.
Blacklight tubes are made of filter glass, which blocks everything except harmless UV-A (which, in a regular fluorescent tube, is blocked by the phosphor coating) and a small amount of purple visible light.
Germicidal tubes are made of quartz. Quartz is transparent to all wavelengths of light from UV-A through UV-C. The electric blue is the color of the bare mercury arc inside. You can see it. You can see it. You can see the electric arc. You can stare into the electric arc. You can worship the electric arc. You can give yourself to the electric arc. Remove your clothes and bathe in the forbidden actinic light of the electric arc. Free yourself. Give yourself to the electric arc. Show the electric arc your self. Give to the electric arc your eyes, your skin. Lie beneath the electric arc and show it you are worthy. Allow the electric arc to bathe your corneas and dermis in its glory. Let the electric arc change you. Let the electric arc change your DNA. Let the electric arc change you. Let the electric arc make you its own. Embrace the tubes and give your body to the electric arc.
back when I was selling fish in the mid-00s, I found the entire section for these things in all the standard fluorescent form factors while flipping through supply catalogues. they were more quite a bit more expensive than equivalently sized fluorescents then, on account of the specialized purpose and quartz.
the supposedly-common chinese use of sterilizer bulbs, however, which is apparently to sterilize entire rooms via combined direct UVC exposure and ozone generation by plugging one into a main socket and leaving the room for a few hours, has led to a proliferation of cheap UVC bulbs available through common retailers.
