My grandfather had an old-school windup watch that he thought would be his most cherished heirloom. Either my sister or I still have it somewhere (safe-deposit box), but it's never really resonated with any of his descendants.

He also had a beat-up metal whiskey flask from his time serving in the Canadian Army in World War I. This is a family treasure! The inner lining is corroded, so you can't drink from it, but it looks stunningly cool on a shelf. It evokes Lt. Fleming and the whole damn war in ways that let one's imagination run wild.

I kept it visible for many years, and when one of my sons wanted it as a keepsake, I said yes -- being able to tell from the way he asked that it would mean a lot to him, too.

In his essay, Silas House (OP) does a great job of highlighting the way that the best heirlooms don't have to be beautiful or costly. Often it's the simple reminders of everyday life that are most evocative to us. We see them -- and we see the hopes and troubles of an entire era gone by.