9/3: a favorite line

My advanced Latin class is reading Vergil's 4th Georgic, and today we reached a beautiful line in which Vergil describes some wool which the nymphs are carding as "dyed with the rich color of glass" (vellera...hyali saturo fucata colore). Most commentators explain that the glass in question must be sea-green since Vergil is talking about sea nymphs. Maybe. But I like to consider the possibility that Vergil is enjoying the paradox of something colored to be deeply transparent...!