RimRim, glassAfter separating the vessel from the blowpipe the rim is always rough and uneven.  Roman glassblowers used several methods to finish the rim and the method and style used may have geographic or chronological significance.   The rim could be left unfinished.  Cold the rim could be ground and perhaps polished.  Hot, the rim could be everted (turned inside out), rounded, rounded and thickend, or folded.  Folding was most common.  See triangular folded rim, simple rolled flaring rim, flaring funnel mouth, rounded rim, rim coil, projecting roll, and collar rim. 

RimRim, glassAfter separating the vessel from the blowpipe the rim is always rough and uneven.  Roman glassblowers used several methods to finish the rim and the method and style used may have geographic or chronological significance.   The rim could be left unfinished.  Cold the rim could be ground and perhaps polished.  Hot, the rim could be everted (turned inside out), rounded, rounded and thickend, or folded.  Folding was most common.  See triangular folded rim, simple rolled flaring rim, flaring funnel mouth, rounded rim, rim coil, projecting roll, and collar rim.