Another option: second hand diamonds, which diamond merchants will tell you don't exist. People die, if they don't pass their stones onto their children, this is where they end up. Sotheby's jewelly auctions. Know what you want, buy stones and ignore settings (they'll be dated and you can sell the metals), and know you're the only retail customer in a room full of diamond merchants. Another option: get a house deposi…
The value is almost guaranteed to appreciate over the course of our marriage (which strikes me as romantic) -- and if there is an unfortunate divorce, she has a chunk of valuable land to sell instead of a useless rock.