This two piece set is actually an individual ash tray (the bowl) and an individual Jelly (the 'plate') The Jelly measures 2 1/2" across. Pattern is marked with the 'Diamond H'.
Only 3 pieces were made in this line - the third being a match holder shaped like a Top Hat. This item is very rare, and was reproduced by Imperial Glass in their carnival color. Heisey's version is noticeably higher quality.