Family heirlooms

Thinking about Jennifer's recent post on wedding rings, I wonder if there's a place for buying some 'big-ticket' items with the intention of making them family heirlooms. For example, what are your thoughts on a young Christian couple investing in a nice engagement ring with the intention of passing it along to their descendants one day as part of their testimony of the sanctity of marriage? After all, "a diamond is forever," or at least that's how DeBeers justifies the diamond's cost.