This lid is made out of a super-light space-age material. Not only is it fully resistant to boiling water, but is semi-transparent so you can see when the water boils. One is reminded of the transparent Aluminum from one of the older Star Trek movies (I think the one with the whale)! The inner shape of the lid insures all the condensing water vapor falls back into the pot, and it does just as well if not better than any metal lid at its prime function - of preventing heat loss.
It is so light you will want to put a small stone on top, Mike Clelland style, so it doesn't blow away. Comes in under 0.2 oz.
I have used this lid for years - perfect lid in every way. These beauties may be hard to find, however. I'm not sure if the cottage industry is still in business.
Add a layer of Al foil under it if you are worried about melting. The foil can be super glued on if a more permanent solution is required. Otherwise boil gently.
Edit: I was wondering about the plastic on my jetboil on full tilt, which this lid also fits. I perma-glued some form fitting Al foil to the bottom - it is still 0.2 Oz as far as my scale can tell. It looks pretty nice and if I worked a little more on the edges sticking out I think I could make it look pretty professional. I think we are now pretty covered for heat, as long as you actually have some water in the pot to sink it.