Are these lampshades?

They look like lampshades but have no top opening. Anyone got any ideas?

 

They look like something you would put on an ordinary candlestick and put a tealight in.

 

Maybe Nils but the base is rounded.

 

Maybe there should be a frame for them to stand in. Other than that, they look like unfinished shades for gas lights. If they are heatproof glass, any attempt at cutting could shatter them.

 

Nils is right, the rubber ring is the give away. They're made to go in a candlestick. The wife has a couple similar.