Does anyone know what type of metal the little silver ring in night sights is made of?
I want to black out the silver rings in a rear rear sight and need to know what to use?
Paint, aluminum black or cold blue, etc.?

I've never seen "silver rings" on a night sight. (Ameriglo, Pacific Tech, Glock, Meprolight)
White or orange epoxy, yes.

Either way a black sharpie will take care of it.

It might depend on whose sights they are, but it seems to me that the lamps of older SIGlites are made from aluminum, and that’s the “ring” we see surrounding the window. In my experience aluminum black doesn’t work well unless the oxidized layer is removed from the metal, and that would be difficult, I believe, with something as small as the night sights, and especially without the possibility of damaging them. I would also be leery of using other harsh chemicals on other types of sights.

As mentioned, a felt tip marker would probably work as well as anything: cheap, quick, easy, and effective.

Yup...original SIGlites were Trijicon and they used aluminum tubes for their Tritium with sapphire lenses...

Bill

Went with aluminum black. Worked perfectly. Sight are now exactly as I wanted them. Front sight has white ring around the tritium and rear sight is blacked out.