When describing the workings of a germicidal tube (fluorescent-style), many people claim that the envelope is made of quartz to transmit UV-C. However, I have yet to see any molybdenum foil seals in any type of fluorescent or non-fluorescent tube. This suggests that (as I expected) they are just using high-purity soft glass, which makes a lot more sense since high temperatures or high pressures aren't involved.

Has anyone ever seen a quartz UV-C tube? I am not talking about high or medium pressure lamps, just low pressure fluorescent-style lamps.
 

Yes I have a couple of Soviet made F8T5 style germicidals in quartz. Also these modern tiny Chinese CCFL style UVC lamps are quartz made with foil lead-outs.

Quartz is superior, of course, but so are production costs, so it get substituted with uviol glass for mass made lamps.

In Russian there is a verb "To Quartz" (some location etc) which means to sterilize it with UVC. Though the lamp this verb came from is a bare arctube of 125W Mercury lamp, not any type of Fluorescent-like lamp

Sure, but i believe the word actually come from some earlier bare medium-high pressure mercury quartz lamps that were called ПРК (ДРТ) in 250+ wattages and appeared in medical UV irradiator apparatus over about 1930-1950's span.

When describing the workings of a germicidal tube (fluorescent-style), many people claim that the envelope is made of quartz to transmit UV-C. However, I have yet to see any molybdenum foil seals in any type of fluorescent or non-fluorescent tube. This suggests that (as I expected) they are just using high-purity soft glass, which makes a lot more sense since high temperatures or high pressures aren't involved.

Has anyone ever seen a quartz UV-C tube? I am not talking about high or medium pressure lamps, just low pressure fluorescent-style lamps.
 

seen plenty, both in real life and here on LG, but they are only usually seen on cheap Chinese germicidal lamps as Quartz has solarisation issues leading bad UV-C output over time

you can usually tell the Quartz lamps by the fact they have no re-entrant stem next to the cathodes and the PL-S/PL-L types will have 2 little nipples on the end of the tube above the cut-n-kiss joint


(tho somewhere on LG is a GxxT6 slimline quartz germicidal tube with a re-entrant quartz stem assembly )

I have a 8W Narva east german germicidal tube that most certainly is made of quartz as you can see the airlines in it.