in Trastevere. "Polvere di Tempo" ("Sands of Time"*) specializes in gifts based on time pieces - watches, globes, hourglasses, meridians, sundials.
The hand-worked pieces, some of them using antiques, are creative. The shop is lovely to look at and the gift packaging superb--including a wax seal with the initial of the person receiving the gift.
Nice Web page too. Better in Italian, though there is an "English" button to click.
via del Moro, 59. I'm not sure of the hours; likely the normal Roman ones (with a break mid-day and not open Sunday or Saturday afternoon or Monday morning, but, hey, it's Trastevere so maybe the hours are more generous).
*The owner and craftsman, Adrian Rodriguez, translates "Polvere di Tempo" as the "Powder of Time." A literal translation probably would be "Dust of Time," but I think "Sands of Time" makes more sense.